The current Tree SRCU implementation schedules a workqueue for every
srcu_data covered by a given leaf srcu_node structure having callbacks,
even if only one of those srcu_data structures actually contains
callbacks. This is clearly inefficient for workloads that don't feature
callbacks everywhere all the time. This commit therefore adds an array
of masks that are used by the leaf srcu_node structures to track exactly
which srcu_data structures contain callbacks.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Mike Galbraith <efault@gmx.de>
When iterating through a map, we need to find a key that does not exist
in the map so map_get_next_key will give us the first key of the map.
This often requires a lot of guessing in production systems.
This patch makes map_get_next_key return the first key when the key
pointer in the parameter is NULL.
Signed-off-by: Teng Qin <qinteng@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
When parsing for the <module:name> format, we use strchr() to look for
the separator, when we know that the module name can't be longer than
MODULE_NAME_LEN. Enforce the same using strnchr().
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Jessica Yu <jeyu@redhat.com>
Now that also the last in-tree user of the xdp_adjust_head bit has
been removed, we can remove the flag from struct bpf_prog altogether.
This, at the same time, also makes sure that any future driver for
XDP comes with bpf_xdp_adjust_head() support right away.
A rejection based on this flag would also mean that tail calls
couldn't be used with such driver as per c2002f9837 ("bpf: fix
checking xdp_adjust_head on tail calls") fix, thus lets not allow
for it in the first place.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull irq fix from Thomas Gleixner:
"The (hopefully) final fix for the irq affinity spreading logic"
* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
genirq/affinity: Fix calculating vectors to assign
There are no users outside of signal.c so make the function static so
the compiler and other developers have that information.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Both conflict were simple overlapping changes.
In the kaweth case, Eric Dumazet's skb_cow() bug fix overlapped the
conversion of the driver in net-next to use in-netdev stats.
Signed-off-by: David S. Miller <davem@davemloft.net>
Modify do_prlimit to call security_task_setrlimit passing the task
whose rlimit we are changing not the tsk->group_leader.
In general this should not matter as the lsms implementing
security_task_setrlimit apparmor and selinux both examine the
task->cred to see what should be allowed on the destination task.
That task->cred is shared between tasks created with CLONE_THREAD
unless thread keyrings are in play, in which case both apparmor and
selinux create duplicate security contexts.
So the only time when it will matter which thread is passed to
security_task_setrlimit is if one of the threads of a process performs
an operation that changes only it's credentials. At which point if a
thread has done that we don't want to hide that information from the
lsms.
So fix the call of security_task_setrlimit. With the removal
of tsk->group_leader this makes the code slightly faster,
more comprehensible and maintainable.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
We are not supposed to add new entries to this thing
any more.
Thanks to Eric Dumazet for noticing this.
Signed-off-by: David S. Miller <davem@davemloft.net>
Constants used for tuning are generally a bad idea, especially as hardware
changes over time. Replace the constant 2 jiffies with sysctl variable
netdev_budget_usecs to enable sysadmins to tune the softirq processing.
Also document the variable.
For example, a very fast machine might tune this to 1000 microseconds,
while my regression testing 486DX-25 needs it to be 4000 microseconds on
a nearly idle network to prevent time_squeeze from being incremented.
Version 2: changed jiffies to microseconds for predictable units.
Signed-off-by: Matthew Whitehead <tedheadster@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, a call to schedule() acts as a Tasks RCU quiescent state
only if a context switch actually takes place. However, just the
call to schedule() guarantees that the calling task has moved off of
whatever tracing trampoline that it might have been one previously.
This commit therefore plumbs schedule()'s "preempt" parameter into
rcu_note_context_switch(), which then records the Tasks RCU quiescent
state, but only if this call to schedule() was -not- due to a preemption.
To avoid adding overhead to the common-case context-switch path,
this commit hides the rcu_note_context_switch() check under an existing
non-common-case check.
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Although Tree SRCU does reduce delays when there is at least one
synchronize_srcu_expedited() invocation pending, srcu_schedule_cbs_snp()
still waits for SRCU_INTERVAL before invoking callbacks. Since
synchronize_srcu_expedited() now posts a callback and waits for
that callback to do a wakeup, this destroys the expedited nature of
synchronize_srcu_expedited(). This destruction became apparent to
Marc Zyngier in the guise of a guest-OS bootup slowdown from five
seconds to no fewer than forty seconds.
This commit therefore invokes callbacks immediately at the end of the
grace period when there is at least one synchronize_srcu_expedited()
invocation pending. This brought Marc's guest-OS bootup times back
into the realm of reason.
Reported-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Marc Zyngier <marc.zyngier@arm.com>
Peter Zijlstra proposed using SRCU to reduce mmap_sem contention [1,2],
however, there are workloads that could result in a high volume of
concurrent invocations of call_srcu(), which with current SRCU would
result in excessive lock contention on the srcu_struct structure's
->queue_lock, which protects SRCU's callback lists. This commit therefore
moves SRCU to per-CPU callback lists, thus greatly reducing contention.
Because a given SRCU instance no longer has a single centralized callback
list, starting grace periods and invoking callbacks are both more complex
than in the single-list Classic SRCU implementation. Starting grace
periods and handling callbacks are now handled using an srcu_node tree
that is in some ways similar to the rcu_node trees used by RCU-bh,
RCU-preempt, and RCU-sched (for example, the srcu_node tree shape is
controlled by exactly the same Kconfig options and boot parameters that
control the shape of the rcu_node tree).
In addition, the old per-CPU srcu_array structure is now named srcu_data
and contains an rcu_segcblist structure named ->srcu_cblist for its
callbacks (and a spinlock to protect this). The srcu_struct gets
an srcu_gp_seq that is used to associate callback segments with the
corresponding completion-time grace-period number. These completion-time
grace-period numbers are propagated up the srcu_node tree so that the
grace-period workqueue handler can determine whether additional grace
periods are needed on the one hand and where to look for callbacks that
are ready to be invoked.
The srcu_barrier() function must now wait on all instances of the per-CPU
->srcu_cblist. Because each ->srcu_cblist is protected by ->lock,
srcu_barrier() can remotely add the needed callbacks. In theory,
it could also remotely start grace periods, but in practice doing so
is complex and racy. And interestingly enough, it is never necessary
for srcu_barrier() to start a grace period because srcu_barrier() only
enqueues a callback when a callback is already present--and it turns out
that a grace period has to have already been started for this pre-existing
callback. Furthermore, it is only the callback that srcu_barrier()
needs to wait on, not any particular grace period. Therefore, a new
rcu_segcblist_entrain() function enqueues the srcu_barrier() function's
callback into the same segment occupied by the last pre-existing callback
in the list. The special case where all the pre-existing callbacks are
on a different list (because they are in the process of being invoked)
is handled by enqueuing srcu_barrier()'s callback into the RCU_DONE_TAIL
segment, relying on the done-callbacks check that takes place after all
callbacks are inovked.
Note that the readers use the same algorithm as before. Note that there
is a separate srcu_idx that tells the readers what counter to increment.
This unfortunately cannot be combined with srcu_gp_seq because they
need to be incremented at different times.
This commit introduces some ugly #ifdefs in rcutorture. These will go
away when I feel good enough about Tree SRCU to ditch Classic SRCU.
Some crude performance comparisons, courtesy of a quickly hacked rcuperf
asynchronous-grace-period capability:
Callback Queuing Overhead
-------------------------
# CPUS Classic SRCU Tree SRCU
------ ------------ ---------
2 0.349 us 0.342 us
16 31.66 us 0.4 us
41 --------- 0.417 us
The times are the 90th percentiles, a statistic that was chosen to reject
the overheads of the occasional srcu_barrier() call needed to avoid OOMing
the test machine. The rcuperf test hangs when running Classic SRCU at 41
CPUs, hence the line of dashes. Despite the hacks to both the rcuperf code
and that statistics, this is a convincing demonstration of Tree SRCU's
performance and scalability advantages.
[1] https://lwn.net/Articles/309030/
[2] https://patchwork.kernel.org/patch/5108281/
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
[ paulmck: Fix initialization if synchronize_srcu_expedited() called first. ]
Per Dan's static checker warning, the code that returns NULL was removed
in 2010, so this patch updates the comments and fixes the code
assumptions.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Have the traceon/off function probe triggers affect only the instance they
are set in. This required making the trace_on/off accessible for other files
in the tracing directory.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Modify the snapshot probe trigger to work with instances. This way the
snapshot function trigger will only affect the instance that it is added to
in the set_ftrace_filter file.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Pass around the local trace_array that is the descriptor for tracing
instances, when enabling and disabling probes. This by default sets the
enable/disable of event probe triggers to work with instances.
The other probes will need some more work to get them working with
instances.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
With the redesign of the registration and execution of the function probes
(triggers), data can now be passed from the setup of the probe to the probe
callers that are specific to the trace_array it is on. Although, all probes
still only affect the toplevel trace array, this change will allow for
instances to have their own probes separated from other instances and the
top array.
That is, something like the stacktrace probe can be set to trace only in an
instance and not the toplevel trace array. This isn't implement yet, but
this change sets the ground work for the change.
When a probe callback is triggered (someone writes the probe format into
set_ftrace_filter), it calls register_ftrace_function_probe() passing in
init_data that will be used to initialize the probe. Then for every matching
function, register_ftrace_function_probe() will call the probe_ops->init()
function with the init data that was passed to it, as well as an address to
a place holder that is associated with the probe and the instance. The first
occurrence will have a NULL in the pointer. The init() function will then
initialize it. If other probes are added, or more functions are part of the
probe, the place holder will be passed to the init() function with the place
holder data that it was initialized to the last time.
Then this place_holder is passed to each of the other probe_ops functions,
where it can be used in the function callback. When the probe_ops free()
function is called, it can be called either with the rip of the function
that is being removed from the probe, or zero, indicating that there are no
more functions attached to the probe, and the place holder is about to be
freed. This gives the probe_ops a way to free the data it assigned to the
place holder if it was allocade during the first init call.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
In order to eventually have each trace_array instance have its own unique
set of function probes (triggers), the trace array needs to hold the ops and
the filters for the probes.
This is the first step to accomplish this. Instead of having the private
data of the probe ops point to the trace_array, create a separate list that
the trace_array holds. There's only one private_data for a probe, we need
one per trace_array. The probe ftrace_ops will be dynamically created for
each instance, instead of being static.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Pass the trace_array associated to a ftrace_probe_ops into the probe_ops
func(), init() and free() functions. The trace_array is the descriptor that
describes a tracing instance. This will help create the infrastructure that
will allow having function probes unique to tracing instances.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Add a link list to the trace_array to hold func probes that are registered.
Currently, all function probes are the same for all instances as it was
before, that is, only the top level trace_array holds the function probes.
But this lays the ground work to have function probes be attached to
individual instances, and having the event trigger only affect events in the
given instance. But that work is still to be done.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
If the ftrace_hash_move_and_update_ops() fails, and an ops->free() function
exists, then it needs to be called on all the ops that were added by this
registration.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Now that the function probes have their own ftrace_ops, there's no reason to
continue using the ftrace_func_hash to find which probe to call in the
function callback. The ops that is passed in to the function callback is
part of the probe_ops to call.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Have the function probes have their own ftrace_ops, and remove the
trace_probe_ops. This simplifies some of the ftrace infrastructure code.
Individual entries for each function is still allocated for the use of the
output for set_ftrace_filter, but they will be removed soon too.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Currently unregister_ftrace_function_probe_func() is a void function. It
does not give any feedback if an error occurred or no item was found to
remove and nothing was done.
Change it to return status and success if it removed something. Also update
the callers to return that feedback to the user.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
The processes of updating a ops filter_hash is a bit complex, and requires
setting up an old hash to perform the update. This is done exactly the same
in two locations for the same reasons. Create a helper function that does it
in one place.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
No users of the function probes uses the data field anymore. Remove it, and
change the init function to take a void *data parameter instead of a
void **data, because the init will just get the data that the registering
function was received, and there's no state after it is called.
The other functions for ftrace_probe_ops still take the data parameter, but
it will currently only be passed NULL. It will stay as a parameter for
future data to be passed to these functions.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
None of the probe users uses the data field anymore of the entry. They all
have their own print() function. Remove showing the data field in the
generic function as the data field will be going away.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
There are no users of unregister_ftrace_function_probe_all(). The only probe
function that is used is unregister_ftrace_function_probe_func(). Rename the
internal static function __unregister_ftrace_function_probe() to
unregister_ftrace_function_probe_func() and make it global.
Also remove the PROBE_TEST_FUNC as it would be always set.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Nothing calls unregister_ftrace_function_probe(). Remove it as well as the
flag PROBE_TEST_DATA, as this function was the only one to set it.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
As the data pointer for individual ips will soon be removed and no longer
passed to the callback function probe handlers, convert the rest of the function
trigger counters over to the new ftrace_func_mapper helper functions.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
As the data pointer for individual ips will soon be removed and no longer
passed to the callback function probe handlers, convert the snapshot
trigger counter over to the new ftrace_func_mapper helper functions.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
In order to move the ops to the function probes directly, they need a way to
map function ips to their own data without depending on the infrastructure
of the function probes, as the data field will be going away.
New helper functions are added that are based on the ftrace_hash code.
ftrace_func_mapper functions are there to let the probes map ips to their
data. These can be allocated by the probe ops, and referenced in the
function callbacks.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
In preparation to cleaning up the probe function registration code, the
"data" parameter will eventually be removed from the probe->func() call.
Instead it will receive its own "ops" function, in which it can set up its
own data that it needs to map.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
As nothing outside the tracing directory uses the function command mechanism,
I'm moving the prototypes out of the include/linux/ftrace.h and into the
local kernel/trace/trace.h header. I plan on making them hook to the
trace_array structure which is local to kernel/trace, and I do not want to
expose it to the rest of the kernel. This requires that the command functions
must also be local to tracing. But luckily nothing else uses them.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
One is a race condition when enabling the snapshot function probe
trigger. It enables the probe before allocating the snapshot, and
if the probe triggers first, it stops tracing with a warning that
the snapshot buffer was not allocated.
The seconds is that the snapshot file should show how to use it when
it is empty. But a bug fix from long ago broke the "is empty" test
and the snapshot file no longer displays the help message.
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Merge tag 'trace-v4.11-rc5-5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull two more ftrace fixes from Steven Rostedt:
"While continuing my development, I uncovered two more small bugs.
One is a race condition when enabling the snapshot function probe
trigger. It enables the probe before allocating the snapshot, and if
the probe triggers first, it stops tracing with a warning that the
snapshot buffer was not allocated.
The seconds is that the snapshot file should show how to use it when
it is empty. But a bug fix from long ago broke the "is empty" test and
the snapshot file no longer displays the help message"
* tag 'trace-v4.11-rc5-5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
ring-buffer: Have ring_buffer_iter_empty() return true when empty
tracing: Allocate the snapshot buffer before enabling probe
A function in kernel/bpf/syscall.c which got a bug fix in 'net'
was moved to kernel/bpf/verifier.c in 'net-next'.
Signed-off-by: David S. Miller <davem@davemloft.net>
The vectors_per_node is calculated from the remaining available vectors.
The current vector starts after pre_vectors, so we need to subtract that
from the current to properly account for the number of remaining vectors
to assign.
Fixes: 3412386b53 ("irq/affinity: Fix extra vecs calculation")
Reported-by: Andrei Vagin <avagin@virtuozzo.com>
Signed-off-by: Keith Busch <keith.busch@intel.com>
Link: http://lkml.kernel.org/r/1492645870-13019-1-git-send-email-keith.busch@intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
commit 239aeba764 ("perf powerpc: Fix kprobe and kretprobe handling with
kallsyms on ppc64le") changed how we use the offset field in struct kprobe on
ABIv2. perf now offsets from the global entry point if an offset is specified
and otherwise chooses the local entry point.
Fix the same in kernel for kprobe API users. We do this by extending
kprobe_lookup_name() to accept an additional parameter to indicate the offset
specified with the kprobe registration. If offset is 0, we return the local
function entry and return the global entry point otherwise.
With:
# cd /sys/kernel/debug/tracing/
# echo "p _do_fork" >> kprobe_events
# echo "p _do_fork+0x10" >> kprobe_events
before this patch:
# cat ../kprobes/list
c0000000000d0748 k _do_fork+0x8 [DISABLED]
c0000000000d0758 k _do_fork+0x18 [DISABLED]
c0000000000412b0 k kretprobe_trampoline+0x0 [OPTIMIZED]
and after:
# cat ../kprobes/list
c0000000000d04c8 k _do_fork+0x8 [DISABLED]
c0000000000d04d0 k _do_fork+0x10 [DISABLED]
c0000000000412b0 k kretprobe_trampoline+0x0 [OPTIMIZED]
Acked-by: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The macro is now pretty long and ugly on powerpc. In the light of further
changes needed here, convert it to a __weak variant to be over-ridden with a
nicer looking function.
Suggested-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Skip preparing optprobe if the probe is ftrace-based, since anyway, it
must not be optimized (or already optimized by ftrace).
Tested-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
timer_migration sysctl acts as a boolean switch, so the allowed values
should be restricted to 0 and 1.
Add the necessary extra fields to the sysctl table entry to enforce that.
[ tglx: Rewrote changelog ]
Signed-off-by: Myungho Jung <mhjungk@gmail.com>
Link: http://lkml.kernel.org/r/1492640690-3550-1-git-send-email-mhjungk@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
I noticed that reading the snapshot file when it is empty no longer gives a
status. It suppose to show the status of the snapshot buffer as well as how
to allocate and use it. For example:
># cat snapshot
# tracer: nop
#
#
# * Snapshot is allocated *
#
# Snapshot commands:
# echo 0 > snapshot : Clears and frees snapshot buffer
# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.
# Takes a snapshot of the main buffer.
# echo 2 > snapshot : Clears snapshot buffer (but does not allocate or free)
# (Doesn't have to be '2' works with any number that
# is not a '0' or '1')
But instead it just showed an empty buffer:
># cat snapshot
# tracer: nop
#
# entries-in-buffer/entries-written: 0/0 #P:4
#
# _-----=> irqs-off
# / _----=> need-resched
# | / _---=> hardirq/softirq
# || / _--=> preempt-depth
# ||| / delay
# TASK-PID CPU# |||| TIMESTAMP FUNCTION
# | | | |||| | |
What happened was that it was using the ring_buffer_iter_empty() function to
see if it was empty, and if it was, it showed the status. But that function
was returning false when it was empty. The reason was that the iter header
page was on the reader page, and the reader page was empty, but so was the
buffer itself. The check only tested to see if the iter was on the commit
page, but the commit page was no longer pointing to the reader page, but as
all pages were empty, the buffer is also.
Cc: stable@vger.kernel.org
Fixes: 651e22f270 ("ring-buffer: Always reset iterator to reader page")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Currently the snapshot trigger enables the probe and then allocates the
snapshot. If the probe triggers before the allocation, it could cause the
snapshot to fail and turn tracing off. It's best to allocate the snapshot
buffer first, and then enable the trigger. If something goes wrong in the
enabling of the trigger, the snapshot buffer is still allocated, but it can
also be freed by the user by writting zero into the snapshot buffer file.
Also add a check of the return status of alloc_snapshot().
Cc: stable@vger.kernel.org
Fixes: 77fd5c15e3 ("tracing: Add snapshot trigger to function probes")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit just changes a "the the" to "the" to reduce repetition.
Reported-by: Michalis Kokologiannakis <mixaskok@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit makes the parse_rcu_nocb_poll() function assign true
(rather than the constant 1) to the bool variable rcu_nocb_poll.
Signed-off-by: Nicholas Mc Guire <der.herr@hofr.at>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The beenonline variable is declared bool so there is no need for an
explicit comparison, especially not against the constant zero.
Signed-off-by: Nicholas Mc Guire <der.herr@hofr.at>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The rcu_nocb_gp_cleanup() function is now invoked elsewhere, so this
commit drags this comment into the year 2017.
Reported-by: Michalis Kokologiannakis <mixaskok@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit changes lockdep splats to begin lines with "WARNING" and
to use pr_warn() instead of printk(). This change eases scripted
analysis of kernel console output.
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
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Merge tag 'v4.11-rc7' into drm-next
Backmerge Linux 4.11-rc7 from Linus tree, to fix some
conflicts that were causing problems with the rerere cache
in drm-tip.
Pull sparc fixes from David Miller:
"Two Sparc bug fixes from Daniel Jordan and Nitin Gupta"
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc:
sparc64: Fix hugepage page table free
sparc64: Use LOCKDEP_SMALL, not PROVE_LOCKING_SMALL
Pull networking fixes from David Miller:
1) BPF tail call handling bug fixes from Daniel Borkmann.
2) Fix allowance of too many rx queues in sfc driver, from Bert
Kenward.
3) Non-loopback ipv6 packets claiming src of ::1 should be dropped,
from Florian Westphal.
4) Statistics requests on KSZ9031 can crash, fix from Grygorii
Strashko.
5) TX ring handling fixes in mediatek driver, from Sean Wang.
6) ip_ra_control can deadlock, fix lock acquisition ordering to fix,
from Cong WANG.
7) Fix use after free in ip_recv_error(), from Willem de Buijn.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net:
bpf: fix checking xdp_adjust_head on tail calls
bpf: fix cb access in socket filter programs on tail calls
ipv6: drop non loopback packets claiming to originate from ::1
net: ethernet: mediatek: fix inconsistency of port number carried in TXD
net: ethernet: mediatek: fix inconsistency between TXD and the used buffer
net: phy: micrel: fix crash when statistic requested for KSZ9031 phy
net: vrf: Fix setting NLM_F_EXCL flag when adding l3mdev rule
net: thunderx: Fix set_max_bgx_per_node for 81xx rgx
net-timestamp: avoid use-after-free in ip_recv_error
ipv4: fix a deadlock in ip_ra_control
sfc: limit the number of receive queues
CONFIG_PROVE_LOCKING_SMALL shrinks the memory usage of lockdep so the
kernel text, data, and bss fit in the required 32MB limit, but this
option is not set for every config that enables lockdep.
A 4.10 kernel fails to boot with the console output
Kernel: Using 8 locked TLB entries for main kernel image.
hypervisor_tlb_lock[2000000:0:8000000071c007c3:1]: errors with f
Program terminated
with these config options
CONFIG_LOCKDEP=y
CONFIG_LOCK_STAT=y
CONFIG_PROVE_LOCKING=n
To fix, rename CONFIG_PROVE_LOCKING_SMALL to CONFIG_LOCKDEP_SMALL, and
enable this option with CONFIG_LOCKDEP=y so we get the reduced memory
usage every time lockdep is turned on.
Tested that CONFIG_LOCKDEP_SMALL is set to 'y' if and only if
CONFIG_LOCKDEP is set to 'y'. When other lockdep-related config options
that select CONFIG_LOCKDEP are enabled (e.g. CONFIG_LOCK_STAT or
CONFIG_PROVE_LOCKING), verified that CONFIG_LOCKDEP_SMALL is also
enabled.
Fixes: e6b5f1be7a ("config: Adding the new config parameter CONFIG_PROVE_LOCKING_SMALL for sparc")
Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Reviewed-by: Babu Moger <babu.moger@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
A group of Linux kernel hackers reported chasing a bug that resulted
from their assumption that SLAB_DESTROY_BY_RCU provided an existence
guarantee, that is, that no block from such a slab would be reallocated
during an RCU read-side critical section. Of course, that is not the
case. Instead, SLAB_DESTROY_BY_RCU only prevents freeing of an entire
slab of blocks.
However, there is a phrase for this, namely "type safety". This commit
therefore renames SLAB_DESTROY_BY_RCU to SLAB_TYPESAFE_BY_RCU in order
to avoid future instances of this sort of confusion.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: <linux-mm@kvack.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
[ paulmck: Add comments mentioning the old name, as requested by Eric
Dumazet, in order to help people familiar with the old name find
the new one. ]
Acked-by: David Rientjes <rientjes@google.com>
This allows callers to get back at them instead of having to store it in
another variable.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
The TREE_SRCU rewrite is large and a bit on the non-simple side, so
this commit helps reduce risk by allowing the old v4.11 SRCU algorithm
to be selected using a new CLASSIC_SRCU Kconfig option that depends
on RCU_EXPERT. The default is to use the new TREE_SRCU and TINY_SRCU
algorithms, in order to help get these the testing that they need.
However, if your users do not require the update-side scalability that
is to be provided by TREE_SRCU, select RCU_EXPERT and then CLASSIC_SRCU
to revert back to the old classic SRCU algorithm.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The srcu_torture_stats() function is adapted to the specific srcu_struct
layout traditionally used by SRCU. This commit therefore adds support
for Tiny SRCU.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
In response to automated complaints about modifications to SRCU
increasing its size, this commit creates a tiny SRCU that is
used in SMP=n && PREEMPT=n builds.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
SRCU's implementation of expedited grace periods has always assumed
that the SRCU instance is idle when the expedited request arrives.
This commit improves this a bit by maintaining a count of the number
of outstanding expedited requests, thus allowing prior non-expedited
grace periods accommodate these requests by shifting to expedited mode.
However, any non-expedited wait already in progress will still wait for
the full duration.
Improved control of expedited grace periods is planned, but one step
at a time.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Updating ->srcu_state and ->srcu_gp_seq will lead to extremely complex
race conditions given multiple callback queues, so this commit takes
advantage of the two-bit state now available in rcu_seq counters to
store the state in the bottom two bits of ->srcu_gp_seq.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit increases the number of reserved bits at the bottom of an
rcu_seq grace-period counter from one to two, as will be needed to
accommodate SRCU's three-state grace periods.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The expedited grace-period code contains several open-coded shifts
know the format of an rcu_seq grace-period counter, which is not
particularly good style. This commit therefore creates a new
rcu_seq_ctr() function that extracts the counter portion of the
counter, and an rcu_seq_state() function that extracts the low-order
state bit. This commit prepares for SRCU callback parallelization,
which will require two state bits.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit makes the num_rcu_lvl[] array external so that SRCU can
make use of it for initializing its upcoming srcu_node tree.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit moves rcu_for_each_node_breadth_first(),
rcu_for_each_nonleaf_node_breadth_first(), and
rcu_for_each_leaf_node() from kernel/rcu/tree.h to
kernel/rcu/rcu.h so that SRCU can access them.
This commit is code-movement only.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit moves the rcu_init_levelspread() function from
kernel/rcu/tree.c to kernel/rcu/rcu.h so that SRCU can access it. This is
another step towards enabling SRCU to create its own combining tree.
This commit is code-movement only, give or take knock-on adjustments.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit moves the C preprocessor code that defines the default shape
of the rcu_node combining tree to a new include/linux/rcu_node_tree.h
file as a first step towards enabling SRCU to create its own combining
tree, which in turn enables SRCU to implement per-CPU callback handling,
thus avoiding contention on the lock currently guarding the single list
of callbacks. Note that users of SRCU still need to know the size of
the srcu_struct structure, hence include/linux rather than kernel/rcu.
This commit is code-movement only.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit switches SRCU from custom-built callback queues to the new
rcu_segcblist structure. This change associates grace-period sequence
numbers with groups of callbacks, which will be needed for efficient
processing of per-CPU callbacks.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit adds grace-period sequence numbers, which will be used to
handle mid-boot grace periods and per-CPU callback lists.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The current SRCU grace-period processing might never reach the last
portion of srcu_advance_batches(). This is OK given the current
implementation, as the first portion, up to the try_check_zero()
following the srcu_flip() is sufficient to drive grace periods forward.
However, it has the unfortunate side-effect of making it impossible to
determine when a given grace period has ended, and it will be necessary
to efficiently trace ends of grace periods in order to efficiently handle
per-CPU SRCU callback lists.
This commit therefore adds states to the SRCU grace-period processing,
so that the end of a given SRCU grace period is marked by the transition
to the SRCU_STATE_DONE state.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit simplifies the SRCU state machine by pushing the
srcu_advance_batches() idle-SRCU fastpath into the common case. This is
done by giving srcu_reschedule() a delay parameter, which is zero in
the call from srcu_advance_batches().
This commit is a step towards numbering callbacks in order to
efficiently handle per-CPU callback lists.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The rcu_seq_end() function increments seq signifying completion
of a grace period, after that checks that the seq is even and wakes
_synchronize_rcu_expedited(). The _synchronize_rcu_expedited() function
uses wait_event() to wait for even seq. The problem is that wait_event()
can return as soon as seq becomes even without waiting for the wakeup.
In such case the warning in rcu_seq_end() can falsely fire if the next
expedited grace period starts before the check.
Check that seq has good value before incrementing it.
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Cc: syzkaller@googlegroups.com
Cc: linux-kernel@vger.kernel.org
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: josh@joshtriplett.org
Cc: jiangshanlai@gmail.com
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
syzkaller-triggered warning:
WARNING: CPU: 0 PID: 4832 at kernel/rcu/tree.c:3533
rcu_seq_end+0x110/0x140 kernel/rcu/tree.c:3533
CPU: 0 PID: 4832 Comm: kworker/0:3 Not tainted 4.10.0+ #276
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
Workqueue: events wait_rcu_exp_gp
Call Trace:
__dump_stack lib/dump_stack.c:15 [inline]
dump_stack+0x2ee/0x3ef lib/dump_stack.c:51
panic+0x1fb/0x412 kernel/panic.c:179
__warn+0x1c4/0x1e0 kernel/panic.c:540
warn_slowpath_null+0x2c/0x40 kernel/panic.c:583
rcu_seq_end+0x110/0x140 kernel/rcu/tree.c:3533
rcu_exp_gp_seq_end kernel/rcu/tree_exp.h:36 [inline]
rcu_exp_wait_wake+0x8a9/0x1330 kernel/rcu/tree_exp.h:517
rcu_exp_sel_wait_wake kernel/rcu/tree_exp.h:559 [inline]
wait_rcu_exp_gp+0x83/0xc0 kernel/rcu/tree_exp.h:570
process_one_work+0xc06/0x1c20 kernel/workqueue.c:2096
worker_thread+0x223/0x19c0 kernel/workqueue.c:2230
kthread+0x326/0x3f0 kernel/kthread.c:227
ret_from_fork+0x31/0x40 arch/x86/entry/entry_64.S:430
---
Expedited grace periods use workqueue handlers that wake up the requesters,
but there is no lock mediating this wakeup. Therefore, memory barriers
are required to ensure that the handler's memory references are seen by
all to occur before synchronize_*_expedited() returns to its caller.
Possibly detected by syzkaller.
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit moves rcu_seq_start(), rcu_seq_end(), rcu_seq_snap(),
and rcu_seq_done() from kernel/rcu/tree.c to kernel/rcu/rcu.h.
This will allow SRCU to use these functions, which in turn will
allow SRCU to move from a single global callback queue to a
per-CPU callback queue.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit adds single-element dequeue functions to rcu_segcblist.
These are less efficient than using the extract and insert functions,
but allow more precise debugging code. These functions are thus
expected to be used only in debug builds, for example, CONFIG_PROVE_RCU.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit checks for pre-scheduler state, and if that early in the
boot process, synchronize_srcu() and friends are no-ops.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This is primarily a code-movement commit in preparation for allowing
SRCU to handle early-boot SRCU grace periods.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
RCU has only one multi-tail callback list, which is implemented via
the nxtlist, nxttail, nxtcompleted, qlen_lazy, and qlen fields in the
rcu_data structure, and whose operations are open-code throughout the
Tree RCU implementation. This has been more or less OK in the past,
but upcoming callback-list optimizations in SRCU could really use
a multi-tail callback list there as well.
This commit therefore abstracts the multi-tail callback list handling
into a new kernel/rcu/rcu_segcblist.h file, and uses this new API.
The simple head-and-tail pointer callback list is also abstracted and
applied everywhere except for the NOCB callback-offload lists. (Yes,
the plan is to apply them there as well, but this commit is already
bigger than would be good.)
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
If the RCU_EXPERT Kconfig option is not set (the default), then the
RCU_FANOUT_LEAF Kconfig option will not be defined, which will cause
the leaf-level rcu_node tree fanout to default to 32 on 32-bit systems
and 64 on 64-bit systems. This can result in excessive lock contention.
This commit therefore changes the computation of the leaf-level rcu_node
tree fanout so that the result will be 16 unless an explicit Kconfig or
kernel-boot setting says otherwise.
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The rcu_all_qs() and rcu_note_context_switch() do a series of checks,
taking various actions to supply RCU with quiescent states, depending
on the outcomes of the various checks. This is a bit much for scheduling
fastpaths, so this commit creates a separate ->rcu_urgent_qs field in
the rcu_dynticks structure that acts as a global guard for these checks.
Thus, in the common case, rcu_all_qs() and rcu_note_context_switch()
check the ->rcu_urgent_qs field, find it false, and simply return.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
The rcu_momentary_dyntick_idle() function scans the RCU flavors, checking
that one of them still needs a quiescent state before doing an expensive
atomic operation on the ->dynticks counter. However, this check reduces
overhead only after a rare race condition, and increases complexity. This
commit therefore removes the scan and the mechanism enabling the scan.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The rcu_qs_ctr variable is yet another isolated per-CPU variable,
so this commit pulls it into the pre-existing rcu_dynticks per-CPU
structure.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The rcu_sched_qs_mask variable is yet another isolated per-CPU variable,
so this commit pulls it into the pre-existing rcu_dynticks per-CPU
structure.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The current use of "RCU_TRACE(statement);" can cause odd bugs, especially
where "statement" is a local-variable declaration, as it can leave a
misplaced ";" in the source code. This commit therefore converts these
to "RCU_TRACE(statement;)", which avoids the misplaced ";".
Reported-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The current use of "RCU_TRACE(statement);" can cause odd bugs, especially
where "statement" is a local-variable declaration, as it can leave a
misplaced ";" in the source code. This commit therefore converts these
to "RCU_TRACE(statement;)", which avoids the misplaced ";".
Reported-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The current use of "RCU_TRACE(statement);" can cause odd bugs, especially
where "statement" is a local-variable declaration, as it can leave a
misplaced ";" in the source code. This commit therefore converts these
to "RCU_TRACE(statement;)", which avoids the misplaced ";".
Reported-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Users of SRCU are obliged to complete all grace-period activity before
invoking cleanup_srcu_struct(). This means that all calls to either
synchronize_srcu() or synchronize_srcu_expedited() must have returned,
and all calls to call_srcu() must have returned, and the last call to
call_srcu() must have been followed by a call to srcu_barrier().
Furthermore, the caller must have done something to prevent any
further calls to synchronize_srcu(), synchronize_srcu_expedited(),
and call_srcu().
Therefore, if there has ever been an invocation of call_srcu() on
the srcu_struct in question, the sequence of events must be as
follows:
1. Prevent any further calls to call_srcu().
2. Wait for any pre-existing call_srcu() invocations to return.
3. Invoke srcu_barrier().
4. It is now safe to invoke cleanup_srcu_struct().
On the other hand, if there has ever been a call to synchronize_srcu()
or synchronize_srcu_expedited(), the sequence of events must be as
follows:
1. Prevent any further calls to synchronize_srcu() or
synchronize_srcu_expedited().
2. Wait for any pre-existing synchronize_srcu() or
synchronize_srcu_expedited() invocations to return.
3. It is now safe to invoke cleanup_srcu_struct().
If there have been calls to all both types of functions (call_srcu()
and either of synchronize_srcu() and synchronize_srcu_expedited()), then
the caller must do the first three steps of the call_srcu() procedure
above and the first two steps of the synchronize_s*() procedure above,
and only then invoke cleanup_srcu_struct().
Note that cleanup_srcu_struct() does some probabilistic checks
for the caller failing to follow these procedures, in which case
cleanup_srcu_struct() does WARN_ON() and avoids freeing the per-CPU
structures associated with the specified srcu_struct structure.
Reported-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
The srcu_reschedule() function invokes rcu_batch_empty() on each of
the four rcu_batch structures in the srcu_struct in question twice.
Given that this check will also be needed in cleanup_srcu_struct(), this
commit consolidates these four checks into a new rcu_all_batches_empty()
function.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Currently, IPIs are used to force other CPUs to invalidate their TLBs
in response to a kernel virtual-memory mapping change. This works, but
degrades both battery lifetime (for idle CPUs) and real-time response
(for nohz_full CPUs), and in addition results in unnecessary IPIs due to
the fact that CPUs executing in usermode are unaffected by stale kernel
mappings. It would be better to cause a CPU executing in usermode to
wait until it is entering kernel mode to do the flush, first to avoid
interrupting usemode tasks and second to handle multiple flush requests
with a single flush in the case of a long-running user task.
This commit therefore reserves a bit at the bottom of the ->dynticks
counter, which is checked upon exit from extended quiescent states.
If it is set, it is cleared and then a new rcu_eqs_special_exit() macro is
invoked, which, if not supplied, is an empty single-pass do-while loop.
If this bottom bit is set on -entry- to an extended quiescent state,
then a WARN_ON_ONCE() triggers.
This bottom bit may be set using a new rcu_eqs_special_set() function,
which returns true if the bit was set, or false if the CPU turned
out to not be in an extended quiescent state. Please note that this
function refuses to set the bit for a non-nohz_full CPU when that CPU
is executing in usermode because usermode execution is tracked by RCU
as a dyntick-idle extended quiescent state only for nohz_full CPUs.
Reported-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
As nothing outside the tracing directory uses the function probes mechanism,
I'm moving the prototypes out of the include/linux/ftrace.h and into the
local kernel/trace/trace.h header. I plan on making them hook to the
trace_array structure which is local to kernel/trace, and I do not want to
expose it to the rest of the kernel. This requires that the probe functions
must also be local to tracing. But luckily nothing else uses them.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
a pid filter to function tracing in an instance, and then freeing
the instance.
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Merge tag 'trace-v4.11-rc5-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull ftrace fix from Steven Rostedt:
"Namhyung Kim discovered a use after free bug. It has to do with adding
a pid filter to function tracing in an instance, and then freeing the
instance"
* tag 'trace-v4.11-rc5-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
ftrace: Fix function pid filter on instances
All the console driver handling code lives in printk.c.
Move console_init() there as well so console support can still be used
when the TTY code is configured out. No logical changes from this patch.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The function-fork option is same as event-fork that it tracks task
fork/exit and set the pid filter properly. This can be useful if user
wants to trace selected tasks including their children only.
Link: http://lkml.kernel.org/r/20170417024430.21194-3-namhyung@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
When function tracer has a pid filter, it adds a probe to sched_switch
to track if current task can be ignored. The probe checks the
ftrace_ignore_pid from current tr to filter tasks. But it misses to
delete the probe when removing an instance so that it can cause a crash
due to the invalid tr pointer (use-after-free).
This is easily reproducible with the following:
# cd /sys/kernel/debug/tracing
# mkdir instances/buggy
# echo $$ > instances/buggy/set_ftrace_pid
# rmdir instances/buggy
============================================================================
BUG: KASAN: use-after-free in ftrace_filter_pid_sched_switch_probe+0x3d/0x90
Read of size 8 by task kworker/0:1/17
CPU: 0 PID: 17 Comm: kworker/0:1 Tainted: G B 4.11.0-rc3 #198
Call Trace:
dump_stack+0x68/0x9f
kasan_object_err+0x21/0x70
kasan_report.part.1+0x22b/0x500
? ftrace_filter_pid_sched_switch_probe+0x3d/0x90
kasan_report+0x25/0x30
__asan_load8+0x5e/0x70
ftrace_filter_pid_sched_switch_probe+0x3d/0x90
? fpid_start+0x130/0x130
__schedule+0x571/0xce0
...
To fix it, use ftrace_clear_pids() to unregister the probe. As
instance_rmdir() already updated ftrace codes, it can just free the
filter safely.
Link: http://lkml.kernel.org/r/20170417024430.21194-2-namhyung@kernel.org
Fixes: 0c8916c342 ("tracing: Add rmdir to remove multibuffer instances")
Cc: Ingo Molnar <mingo@kernel.org>
Cc: stable@vger.kernel.org
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Commit 17bedab272 ("bpf: xdp: Allow head adjustment in XDP prog")
added the xdp_adjust_head bit to the BPF prog in order to tell drivers
that the program that is to be attached requires support for the XDP
bpf_xdp_adjust_head() helper such that drivers not supporting this
helper can reject the program. There are also drivers that do support
the helper, but need to check for xdp_adjust_head bit in order to move
packet metadata prepended by the firmware away for making headroom.
For these cases, the current check for xdp_adjust_head bit is insufficient
since there can be cases where the program itself does not use the
bpf_xdp_adjust_head() helper, but tail calls into another program that
uses bpf_xdp_adjust_head(). As such, the xdp_adjust_head bit is still
set to 0. Since the first program has no control over which program it
calls into, we need to assume that bpf_xdp_adjust_head() helper is used
upon tail calls. Thus, for the very same reasons in cb_access, set the
xdp_adjust_head bit to 1 when the main program uses tail calls.
Fixes: 17bedab272 ("bpf: xdp: Allow head adjustment in XDP prog")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Cc: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit ff936a04e5 ("bpf: fix cb access in socket filter programs")
added a fix for socket filter programs such that in i) AF_PACKET the
20 bytes of skb->cb[] area gets zeroed before use in order to not leak
data, and ii) socket filter programs attached to TCP/UDP sockets need
to save/restore these 20 bytes since they are also used by protocol
layers at that time.
The problem is that bpf_prog_run_save_cb() and bpf_prog_run_clear_cb()
only look at the actual attached program to determine whether to zero
or save/restore the skb->cb[] parts. There can be cases where the
actual attached program does not access the skb->cb[], but the program
tail calls into another program which does access this area. In such
a case, the zero or save/restore is currently not performed.
Since the programs we tail call into are unknown at verification time
and can dynamically change, we need to assume that whenever the attached
program performs a tail call, that later programs could access the
skb->cb[], and therefore we need to always set cb_access to 1.
Fixes: ff936a04e5 ("bpf: fix cb access in socket filter programs")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
The trace_event benchmark thread runs in kernel space in an infinite loop
while also calling cond_resched() in case anything else wants to schedule
in. Unfortunately, on a PREEMPT kernel, that makes it a nop, in which case,
this will never voluntarily schedule. That will cause synchronize_rcu_tasks()
to forever block on this thread, while it is running.
This is exactly what cond_resched_rcu_qs() is for. Use that instead.
Acked-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
After doing map_perf_test with a much bigger
BPF_F_NO_COMMON_LRU map, the perf report shows a
lot of time spent in rotating the inactive list (i.e.
__bpf_lru_list_rotate_inactive):
> map_perf_test 32 8 10000 1000000 | awk '{sum += $3}END{print sum}'
19644783 (19M/s)
> map_perf_test 32 8 10000000 10000000 | awk '{sum += $3}END{print sum}'
6283930 (6.28M/s)
By inactive, it usually means the element is not in cache. Hence,
there is a need to tune the PERCPU_NR_SCANS value.
This patch finds a better number of elements to
scan during each list rotation. The PERCPU_NR_SCANS (which
is defined the same as PERCPU_FREE_TARGET) decreases
from 16 elements to 4 elements. This change only
affects the BPF_F_NO_COMMON_LRU map.
The test_lru_dist does not show meaningful difference
between 16 and 4. Our production L4 load balancer which uses
the LRU map for conntrack-ing also shows little change in cache
hit rate. Since both benchmark and production data show no
cache-hit difference, PERCPU_NR_SCANS is lowered from 16 to 4.
We can consider making it configurable if we find a usecase
later that shows another value works better and/or use
a different rotation strategy.
After this change:
> map_perf_test 32 8 10000000 10000000 | awk '{sum += $3}END{print sum}'
9240324 (9.2M/s)
i.e. 6.28M/s -> 9.2M/s
The test_lru_dist has not shown meaningful difference:
> test_lru_dist zipf.100k.a1_01.out 4000 1:
nr_misses: 31575 (Before) vs 31566 (After)
> test_lru_dist zipf.100k.a0_01.out 40000 1
nr_misses: 67036 (Before) vs 67031 (After)
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Make the schedutil governor take the initial (default) value of the
rate_limit_us sysfs attribute from the (new) transition_delay_us
policy parameter (to be set by the scaling driver).
That will allow scaling drivers to make schedutil use smaller default
values of rate_limit_us and reduce the default average time interval
between consecutive frequency changes.
Make intel_pstate set transition_delay_us to 500.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
t_hash_start() does not increment *pos, where as t_next() must. But when
t_next() does increment *pos, it must still pass in the original *pos to
t_hash_start() otherwise it will skip the first instance:
# cd /sys/kernel/debug/tracing
# echo schedule:traceoff > set_ftrace_filter
# echo do_IRQ:traceoff > set_ftrace_filter
# echo call_rcu > set_ftrace_filter
# cat set_ftrace_filter
call_rcu
schedule:traceoff:unlimited
do_IRQ:traceoff:unlimited
The above called t_hash_start() from t_start() as there was only one
function (call_rcu), but if we add another function:
# echo xfrm_policy_destroy_rcu >> set_ftrace_filter
# cat set_ftrace_filter
call_rcu
xfrm_policy_destroy_rcu
do_IRQ:traceoff:unlimited
The "schedule:traceoff" disappears.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
CPUCLOCK_PID(which_clock) is a pid value from userspace so compare it
against task_pid_vnr, not current->pid. As task_pid_vnr is in the tasks
pid value in the tasks pid namespace, and current->pid is in the
initial pid namespace.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Pull cgroup fix from Tejun Heo:
"Unfortunately, the commit to fix the cgroup mount race in the previous
pull request can lead to hangs.
The original bug has been around for a while and isn't too likely to
be triggered in usual use cases. Revert the commit for now"
* 'for-4.11-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
Revert "cgroup: avoid attaching a cgroup root to two different superblocks"
bug. This bug has been there sinc function tracing was added way back
when. But my new development depends on this bug being fixed, and it
should be fixed regardless as it causes ftrace to disable itself when
triggered, and a reboot is required to enable it again.
The bug is that the function probe does not disable itself properly
if there's another probe of its type still enabled. For example:
# cd /sys/kernel/debug/tracing
# echo schedule:traceoff > set_ftrace_filter
# echo do_IRQ:traceoff > set_ftrace_filter
# echo \!do_IRQ:traceoff > /debug/tracing/set_ftrace_filter
# echo do_IRQ:traceoff > set_ftrace_filter
The above registers two traceoff probes (one for schedule and one for
do_IRQ, and then removes do_IRQ. But since there still exists one for
schedule, it is not done properly. When adding do_IRQ back, the breakage
in the accounting is noticed by the ftrace self tests, and it causes
a warning and disables ftrace.
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Merge tag 'trace-v4.11-rc5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull ftrace fix from Steven Rostedt:
"While rewriting the function probe code, I stumbled over a long
standing bug. This bug has been there sinc function tracing was added
way back when. But my new development depends on this bug being fixed,
and it should be fixed regardless as it causes ftrace to disable
itself when triggered, and a reboot is required to enable it again.
The bug is that the function probe does not disable itself properly if
there's another probe of its type still enabled. For example:
# cd /sys/kernel/debug/tracing
# echo schedule:traceoff > set_ftrace_filter
# echo do_IRQ:traceoff > set_ftrace_filter
# echo \!do_IRQ:traceoff > /debug/tracing/set_ftrace_filter
# echo do_IRQ:traceoff > set_ftrace_filter
The above registers two traceoff probes (one for schedule and one for
do_IRQ, and then removes do_IRQ.
But since there still exists one for schedule, it is not done
properly. When adding do_IRQ back, the breakage in the accounting is
noticed by the ftrace self tests, and it causes a warning and disables
ftrace"
* tag 'trace-v4.11-rc5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
ftrace: Fix removing of second function probe
This reverts commit bfb0b80db5.
Andrei reports CRIU test hangs with the patch applied. The bug fixed
by the patch isn't too likely to trigger in actual uses. Revert the
patch for now.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Andrei Vagin <avagin@virtuozzo.com>
Link: http://lkml.kernel.org/r/20170414232737.GC20350@outlook.office365.com
Conflicts were simply overlapping changes. In the net/ipv4/route.c
case the code had simply moved around a little bit and the same fix
was made in both 'net' and 'net-next'.
In the net/sched/sch_generic.c case a fix in 'net' happened at
the same time that a new argument was added to qdisc_hash_add().
Signed-off-by: David S. Miller <davem@davemloft.net>
Clarify the scenario described in mark_wake_futex requiring the
smp_store_release(). Update the comment to explicitly refer to the
plist_del now under __unqueue_futex() (previously plist_del was in the
same function as the comment).
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20170414223138.GA4222@fury
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
When requesting a shared irq with IRQF_TRIGGER_NONE then the irqaction
flags get filled with the trigger type from the irq_data:
if (!(new->flags & IRQF_TRIGGER_MASK))
new->flags |= irqd_get_trigger_type(&desc->irq_data);
On the first setup_irq() the trigger type in irq_data is NONE when the
above code executes, then the irq is started up for the first time and
then the actual trigger type gets established, but that's too late to fix
up new->flags.
When then a second user of the irq requests the irq with IRQF_TRIGGER_NONE
its irqaction's triggertype gets set to the actual trigger type and the
following check fails:
if (!((old->flags ^ new->flags) & IRQF_TRIGGER_MASK))
Resulting in the request_irq failing with -EBUSY even though both
users requested the irq with IRQF_SHARED | IRQF_TRIGGER_NONE
Fix this by comparing the new irqaction's trigger type to the trigger type
stored in the irq_data which correctly reflects the actual trigger type
being used for the irq.
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Link: http://lkml.kernel.org/r/20170415100831.17073-1-hdegoede@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
- Unify gemini and moxa irqchips under the faraday banner
- Extend mtk-sysirq to deal with multiple MMIO regions
- ACPI/IORT support for GICv3 ITS platform MSI
- ACPI support for mbigen
- Add mtk-cirq wakeup interrupt controller driver
- Atmel aic5 suspend support
- Allow GPCv2 to be probed both as an irqchip and a device
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Merge tag 'irqchip-4.12' of git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms into irq/core
Pull irqchip updates from Marc Zyngier
- Unify gemini and moxa irqchips under the faraday banner
- Extend mtk-sysirq to deal with multiple MMIO regions
- ACPI/IORT support for GICv3 ITS platform MSI
- ACPI support for mbigen
- Add mtk-cirq wakeup interrupt controller driver
- Atmel aic5 suspend support
- Allow GPCv2 to be probed both as an irqchip and a device
work_on_cpu() is not protected against CPU hotplug. For code which requires
to be either executed on an online CPU or to fail if the CPU is not
available the callsite would have to protect against CPU hotplug.
Provide a function which does get/put_online_cpus() around the call to
work_on_cpu() and fails the call with -ENODEV if the target CPU is not
online.
Preparatory patch to convert several racy task affinity manipulations.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Len Brown <lenb@kernel.org>
Link: http://lkml.kernel.org/r/20170412201042.262610721@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Pull networking fixes from David Miller:
"Things seem to be settling down as far as networking is concerned,
let's hope this trend continues...
1) Add iov_iter_revert() and use it to fix the behavior of
skb_copy_datagram_msg() et al., from Al Viro.
2) Fix the protocol used in the synthetic SKB we cons up for the
purposes of doing a simulated route lookup for RTM_GETROUTE
requests. From Florian Larysch.
3) Don't add noop_qdisc to the per-device qdisc hashes, from Cong
Wang.
4) Don't call netdev_change_features with the team lock held, from
Xin Long.
5) Revert TCP F-RTO extension to catch more spurious timeouts because
it interacts very badly with some middle-boxes. From Yuchung
Cheng.
6) Fix the loss of error values in l2tp {s,g}etsockopt calls, from
Guillaume Nault.
7) ctnetlink uses bit positions where it should be using bit masks,
fix from Liping Zhang.
8) Missing RCU locking in netfilter helper code, from Gao Feng.
9) Avoid double frees and use-after-frees in tcp_disconnect(), from
Eric Dumazet.
10) Don't do a changelink before we register the netdevice in
bridging, from Ido Schimmel.
11) Lock the ipv6 device address list properly, from Rabin Vincent"
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (29 commits)
netfilter: ipt_CLUSTERIP: Fix wrong conntrack netns refcnt usage
netfilter: nft_hash: do not dump the auto generated seed
drivers: net: usb: qmi_wwan: add QMI_QUIRK_SET_DTR for Telit PID 0x1201
ipv6: Fix idev->addr_list corruption
net: xdp: don't export dev_change_xdp_fd()
bridge: netlink: register netdevice before executing changelink
bridge: implement missing ndo_uninit()
bpf: reference may_access_skb() from __bpf_prog_run()
tcp: clear saved_syn in tcp_disconnect()
netfilter: nf_ct_expect: use proper RCU list traversal/update APIs
netfilter: ctnetlink: skip dumping expect when nfct_help(ct) is NULL
netfilter: make it safer during the inet6_dev->addr_list traversal
netfilter: ctnetlink: make it safer when checking the ct helper name
netfilter: helper: Add the rcu lock when call __nf_conntrack_helper_find
netfilter: ctnetlink: using bit to represent the ct event
netfilter: xt_TCPMSS: add more sanity tests on tcph->doff
net: tcp: Increase TCP_MIB_OUTRSTS even though fail to alloc skb
l2tp: don't mask errors in pppol2tp_getsockopt()
l2tp: don't mask errors in pppol2tp_setsockopt()
tcp: restrict F-RTO to work-around broken middle-boxes
...
Pull irq fixes from Thomas Gleixner:
"The irq department provides:
- two fixes for the CPU affinity spread infrastructure to prevent
unbalanced spreading in corner cases which leads to horrible
performance, because interrupts are rather aggregated than spread
- add a missing spinlock initializer in the imx-gpcv2 init code"
* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
irqchip/irq-imx-gpcv2: Fix spinlock initialization
irq/affinity: Fix extra vecs calculation
irq/affinity: Fix CPU spread for unbalanced nodes
struct timespec is not y2038 safe on 32 bit machines. Replace uses of
struct timespec with struct timespec64 in the kernel.
The syscall interfaces themselves will be changed in a separate series.
Note that the restart_block parameter for nanosleep has also been left
unchanged and will be part of syscall series noted above.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Cc: y2038@lists.linaro.org
Cc: john.stultz@linaro.org
Cc: arnd@arndb.de
Link: http://lkml.kernel.org/r/1490555058-4603-8-git-send-email-deepa.kernel@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
struct timespec is not y2038 safe on 32 bit machines. Replace uses of
struct timespec with struct timespec64 in the kernel.
struct itimerspec internally uses struct timespec. Use struct itimerspec64
which uses struct timespec64.
The syscall interfaces themselves will be changed in a separate series.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Cc: y2038@lists.linaro.org
Cc: john.stultz@linaro.org
Cc: arnd@arndb.de
Link: http://lkml.kernel.org/r/1490555058-4603-7-git-send-email-deepa.kernel@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
struct timespec is not y2038 safe on 32 bit machines. Replace uses of
struct timespec with struct timespec64 in the kernel. The syscall
interfaces themselves will be changed in a separate series.
The clock_getres() interface has also been changed to use timespec64 even
though this particular interface is not affected by the y2038 problem. This
helps verification for internal kernel code for y2038 readiness by getting
rid of time_t/ timeval/ timespec completely.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Cc: y2038@lists.linaro.org
Cc: john.stultz@linaro.org
Cc: arnd@arndb.de
Link: http://lkml.kernel.org/r/1490555058-4603-5-git-send-email-deepa.kernel@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
struct timespec is not y2038 safe on 32 bit machines.
The posix clocks apis use struct timespec directly and through struct
itimerspec.
Replace the posix clock interfaces to use struct timespec64 and struct
itimerspec64 instead. Also fix up their implementations accordingly.
Note that the clock_getres() interface has also been changed to use
timespec64 even though this particular interface is not affected by the
y2038 problem. This helps verification for internal kernel code for y2038
readiness by getting rid of time_t/ timeval/ timespec.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Cc: arnd@arndb.de
Cc: y2038@lists.linaro.org
Cc: netdev@vger.kernel.org
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: john.stultz@linaro.org
Link: http://lkml.kernel.org/r/1490555058-4603-3-git-send-email-deepa.kernel@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This fixes the following clang warning when CONFIG_CPUMASK_OFFSTACK=n:
kernel/irq/manage.c:839:28: error: address of array
'desc->irq_common_data.affinity' will always evaluate to 'true'
[-Werror,-Wpointer-bool-conversion]
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Cc: Grant Grundler <grundler@chromium.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Greg Hackmann <ghackmann@google.com>
Cc: Michael Davidson <md@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20170412182030.83657-2-mka@chromium.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
During (post-commit) review Darren spotted a few minor things. One
(harmless AFAICT) type inconsistency and a comment that wasn't as
clear as hoped.
Reported-by: Darren Hart (VMWare) <dvhart@infradead.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Darren Hart (VMware) <dvhart@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Alexander reported a hrtimer debug_object splat:
ODEBUG: free active (active state 0) object type: hrtimer hint: hrtimer_wakeup (kernel/time/hrtimer.c:1423)
debug_object_free (lib/debugobjects.c:603)
destroy_hrtimer_on_stack (kernel/time/hrtimer.c:427)
futex_lock_pi (kernel/futex.c:2740)
do_futex (kernel/futex.c:3399)
SyS_futex (kernel/futex.c:3447 kernel/futex.c:3415)
do_syscall_64 (arch/x86/entry/common.c:284)
entry_SYSCALL64_slow_path (arch/x86/entry/entry_64.S:249)
Which was caused by commit:
cfafcd117d ("futex: Rework futex_lock_pi() to use rt_mutex_*_proxy_lock()")
... losing the hrtimer_cancel() in the shuffle. Where previously the
hrtimer_cancel() was done by rt_mutex_slowlock() we now need to do it
manually.
Reported-by: Alexander Levin <alexander.levin@verizon.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Fixes: cfafcd117d ("futex: Rework futex_lock_pi() to use rt_mutex_*_proxy_lock()")
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1704101802370.2906@nanos
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Now that we have a tool to generate the PELT constants in C form,
use its output as a separate header.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We truncate (and loose) the lower 10 bits of runtime in
___update_load_avg(), this means there's a consistent bias to
under-account tasks. This is esp. significant for small tasks.
Cure this by only forwarding last_update_time to the point we've
actually accounted for, leaving the remainder for the next time.
Reported-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Historically our periods (or p) argument in PELT denoted the number of
full periods (what is now d2). However recent patches have changed
this to the total decay (previously p+1), leading to a confusing
discrepancy between comments and code.
Try and clarify things by making periods (in code) and p (in comments)
be the same thing (again).
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Paul noticed that in the (periods >= LOAD_AVG_MAX_N) case in
__accumulate_sum(), the returned contribution value (LOAD_AVG_MAX) is
incorrect.
This is because at this point, the decay_load() on the old state --
the first step in accumulate_sum() -- will not have resulted in 0, and
will therefore result in a sum larger than the maximum value of our
series. Obviously broken.
Note that:
decay_load(LOAD_AVG_MAX, LOAD_AVG_MAX_N) =
1 (345 / 32)
47742 * - ^ = ~27
2
Not to mention that any further contribution from the d3 segment (our
new period) would also push it over the maximum.
Solve this by noting that we can write our c2 term:
p
c2 = 1024 \Sum y^n
n=1
In terms of our maximum value:
inf inf p
max = 1024 \Sum y^n = 1024 ( \Sum y^n + \Sum y^n + y^0 )
n=0 n=p+1 n=1
Further note that:
inf inf inf
( \Sum y^n ) y^p = \Sum y^(n+p) = \Sum y^n
n=0 n=0 n=p
Combined that gives us:
p
c2 = 1024 \Sum y^n
n=1
inf inf
= 1024 ( \Sum y^n - \Sum y^n - y^0 )
n=0 n=p+1
= max - (max y^(p+1)) - 1024
Further simplify things by dealing with p=0 early on.
Reported-by: Paul Turner <pjt@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yuyang Du <yuyang.du@intel.com>
Cc: linux-kernel@vger.kernel.org
Fixes: a481db34b9 ("sched/fair: Optimize ___update_sched_avg()")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This fixes a math error calculating the extra_vecs. The error assumed
only 1 cpu per vector, but the value needs to account for the actual
number of cpus per vector in order to get the correct remainder for
extra CPU assignment.
Fixes: 7bf8222b9b ("irq/affinity: Fix CPU spread for unbalanced nodes")
Reported-by: Xiaolong Ye <xiaolong.ye@intel.com>
Signed-off-by: Keith Busch <keith.busch@intel.com>
Link: http://lkml.kernel.org/r/1492104492-19943-1-git-send-email-keith.busch@intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Add the base infrastructure and UAPI for netlink extended ACK
reporting. All "manual" calls to netlink_ack() pass NULL for now and
thus don't get extended ACK reporting.
Big thanks goes to Pablo Neira Ayuso for not only bringing up the
whole topic at netconf (again) but also coming up with the nlattr
passing trick and various other ideas.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Reviewed-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The schedutil governor reduces frequencies too fast in some
situations which cases undesirable performance drops to
appear.
To address that issue, make schedutil reduce the frequency slower by
setting it to the average of the value chosen during the previous
iteration of governor computations and the new one coming from its
frequency selection formula.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=194963
Reported-by: John <john.ettedgui@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
If a console was specified by ACPI SPCR table _and_ command line
parameters like "console=ttyAMA0" _and_ "earlycon" were specified,
then log messages appear twice.
The root cause is that the code traverses the list of specified
consoles (the `console_cmdline` array) and stops at the first match.
But it may happen that the same console is referred by the elements
of this array twice:
pl011,mmio,0x87e024000000,115200 -- from SPCR
ttyAMA0 -- from command line
but in this case `preferred_console` points to the second entry and
the flag CON_CONSDEV is not set, so bootconsole is not deregistered.
To fix that, introduce an invariant "The last non-braille console
is always the preferred one" on the entries of the console_cmdline
array. Then traverse it in reverse order to be sure that if
the console is preferred then it will be the first matching entry.
Introduce variable console_cmdline_cnt that keeps the number
of elements of the console_cmdline array (Petr Mladek). It helps
to get rid of the loop that searches for the end of this array.
Link: http://lkml.kernel.org/r/20170405202006.18234-1-aleksey.makarov@linaro.org
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: "Nair, Jayachandran" <Jayachandran.Nair@cavium.com>
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Aleksey Makarov <aleksey.makarov@linaro.org>
Reported-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
The variable selected_console is set in __add_preferred_console()
to point to the last console parameter that was added to the
console_cmdline array.
Rename it to preferred_console so that the name reflects the usage.
Petr Mladek:
"[..] the selected_console/preferred_console
value is used to keep the console first in the console_drivers list.
IMHO, the main effect is that each line will first appear on this
console, see call_console_drivers(). But the message will still
appear also on all other enabled consoles. From this point,
the name "preferred" sounds better to me. More consoles
are selected (enabled) and only one is preferred (first)."
Link: http://lkml.kernel.org/r/20170315102854.1763-3-aleksey.makarov@linaro.org
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: "Nair, Jayachandran" <Jayachandran.Nair@cavium.com>
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Aleksey Makarov <aleksey.makarov@linaro.org>
Suggested-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
The variable preferred_console is used only inside register_console()
and its semantics is boolean. It is negative when no console has been
made preferred.
Make it static bool and rename to has_preferred.
Renaming was suggested by Peter Hurley
Link: http://lkml.kernel.org/r/20170315102854.1763-2-aleksey.makarov@linaro.org
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: "Nair, Jayachandran" <Jayachandran.Nair@cavium.com>
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Aleksey Makarov <aleksey.makarov@linaro.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Pull audit fix from Paul Moore:
"One more small audit fix, this should be the last for v4.11.
Seth Forshee noticed a problem where the audit retry queue wasn't
being flushed properly when audit was enabled and the audit daemon
wasn't running; this patches fixes the problem (see the commit
description for more details on the change).
Both Seth and I have tested this and everything looks good"
* 'stable-4.11' of git://git.infradead.org/users/pcmoore/audit:
audit: make sure we don't let the retry queue grow without bounds
Pull cgroup fixes from Tejun Heo:
"This contains fixes for two long standing subtle bugs:
- kthread_bind() on a new kthread binds it to specific CPUs and
prevents userland from messing with the affinity or cgroup
membership. Unfortunately, for cgroup membership, there's a window
between kthread creation and kthread_bind*() invocation where the
kthread can be moved into a non-root cgroup by userland.
Depending on what controllers are in effect, this can assign the
kthread unexpected attributes. For example, in the reported case,
workqueue workers ended up in a non-root cpuset cgroups and had
their CPU affinities overridden. This broke workqueue invariants
and led to workqueue stalls.
Fixed by closing the window between kthread creation and
kthread_bind() as suggested by Oleg.
- There was a bug in cgroup mount path which could allow two
competing mount attempts to attach the same cgroup_root to two
different superblocks.
This was caused by mishandling return value from kernfs_pin_sb().
Fixed"
* 'for-4.11-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup: avoid attaching a cgroup root to two different superblocks
cgroup, kthread: close race window where new kthreads can be migrated to non-root cgroups
klp_init_transition() does not set func->transition for immediate patches.
Then klp_ftrace_handler() could use the new code immediately. As a result,
it is not safe to put the livepatch module in klp_cancel_transition().
This patch reverts most of the last minute changes klp_cancel_transition().
It keeps the warning about a misuse because it still makes sense.
Fixes: 3ec24776bf ("livepatch: allow removal of a disabled patch")
Signed-off-by: Petr Mladek <pmladek@suse.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Paul E. McKenney