On three of the several paths in entry_64.S that call
do_notify_resume() on the way back to user mode, we fail to properly
check again for newly-arrived work that requires another call to
do_notify_resume() before going to user mode. These paths set the
mask to check only _TIF_NEED_RESCHED, but this is wrong. The other
paths that lead to do_notify_resume() do this correctly already, and
entry_32.S does it correctly in all cases.
All paths back to user mode have to check all the _TIF_WORK_MASK
flags at the last possible stage, with interrupts disabled.
Otherwise, we miss any flags (TIF_SIGPENDING for example) that were
set any time after we entered do_notify_resume(). More work flags
can be set (or left set) synchronously inside do_notify_resume(), as
TIF_SIGPENDING can be, or asynchronously by interrupts or other CPUs
(which then send an asynchronous interrupt).
There are many different scenarios that could hit this bug, most of
them races. The simplest one to demonstrate does not require any
race: when one signal has done handler setup at the check before
returning from a syscall, and there is another signal pending that
should be handled. The second signal's handler should interrupt the
first signal handler before it actually starts (so the interrupted PC
is still at the handler's entry point). Instead, it runs away until
the next kernel entry (next syscall, tick, etc).
This test behaves correctly on 32-bit kernels, and fails on 64-bit
(either 32-bit or 64-bit test binary). With this fix, it works.
#define _GNU_SOURCE
#include <stdio.h>
#include <signal.h>
#include <string.h>
#include <sys/ucontext.h>
#ifndef REG_RIP
#define REG_RIP REG_EIP
#endif
static sig_atomic_t hit1, hit2;
static void
handler (int sig, siginfo_t *info, void *ctx)
{
ucontext_t *uc = ctx;
if ((void *) uc->uc_mcontext.gregs[REG_RIP] == &handler)
{
if (sig == SIGUSR1)
hit1 = 1;
else
hit2 = 1;
}
printf ("%s at %#lx\n", strsignal (sig),
uc->uc_mcontext.gregs[REG_RIP]);
}
int
main (void)
{
struct sigaction sa;
sigset_t set;
sigemptyset (&sa.sa_mask);
sa.sa_flags = SA_SIGINFO;
sa.sa_sigaction = &handler;
if (sigaction (SIGUSR1, &sa, NULL)
|| sigaction (SIGUSR2, &sa, NULL))
return 2;
sigemptyset (&set);
sigaddset (&set, SIGUSR1);
sigaddset (&set, SIGUSR2);
if (sigprocmask (SIG_BLOCK, &set, NULL))
return 3;
printf ("main at %p, handler at %p\n", &main, &handler);
raise (SIGUSR1);
raise (SIGUSR2);
if (sigprocmask (SIG_UNBLOCK, &set, NULL))
return 4;
if (hit1 + hit2 == 1)
{
puts ("PASS");
return 0;
}
puts ("FAIL");
return 1;
}
Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
We have two conflicting DMA-based quirks in there for the same set of
boxes (HP nx6325 and nx6125) and one of them actually breaks my box.
So remove the extra code.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: =?iso-8859-1?q?T=F6r=F6k_Edwin?= <edwintorok@gmail.com>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Remove explicit lock_kernel() calls and document why the code is safe.
Signed-off-by: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
This patch corrects the handling of write operations to the IPMI watchdog
to work as intended by returning the number of characters actually
processed. Without this patch, an "echo V >/dev/watchdog" enables the
watchdog if IPMI is providing the watchdog function.
Signed-off-by: Mark Rustad <MRustad@gmail.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
In the course of the recent unification of the NMI watchdog an assignment
to timer_ack to switch off unnecesary POLL commands to the 8259A in the
case of a watchdog failure has been accidentally removed. The statement
used to be limited to the 32-bit variation as since the rewrite of the
timer code it has been relevant for the 82489DX only. This change brings
it back.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
There is no such entity as ISA IRQ2. The ACPI spec does not make it
explicitly clear, but does not preclude it either -- all it says is ISA
legacy interrupts are identity mapped by default (subject to overrides),
but it does not state whether IRQ2 exists or not. As a result if there is
no IRQ0 override, then IRQ2 is normally initialised as an ISA interrupt,
which implies an edge-triggered line, which is unmasked by default as this
is what we do for edge-triggered I/O APIC interrupts so as not to miss an
edge.
To the best of my knowledge it is useless, as IRQ2 has not been in use
since the PC/AT as back then it was taken by the 8259A cascade interrupt
to the slave, with the line position in the slot rerouted to newly-created
IRQ9. No device could thus make use of this line with the pair of 8259A
chips. Now in theory INTIN2 of the I/O APIC may be usable, but the
interrupt of the device wired to it would not be available in the PIC mode
at all, so I seriously doubt if anybody decided to reuse it for a regular
device.
However there are two common uses of INTIN2. One is for IRQ0, with an
ACPI interrupt override (or its equivalent in the MP table). But in this
case IRQ2 is gone entirely with INTIN0 left vacant. The other one is for
an 8959A ExtINTA cascade. In this case IRQ0 goes to INTIN0 and if ACPI is
used INTIN2 is assumed to be IRQ2 (there is no override and ACPI has no
way to report ExtINTA interrupts). This is where a problem happens.
The problem is INTIN2 is configured as a native APIC interrupt, with a
vector assigned and the mask cleared. And the line may indeed get active
and inject interrupts if the master 8959A has its timer interrupt enabled
(it might happen for other interrupts too, but they are normally masked in
the process of rerouting them to the I/O APIC). There are two cases where
it will happen:
* When the I/O APIC NMI watchdog is enabled. This is actually a misnomer
as the watchdog pulses are delivered through the 8259A to the LINT0
inputs of all the local APICs in the system. The implication is the
output of the master 8259A goes high and low repeatedly, signalling
interrupts to INTIN2 which is enabled too!
[The origin of the name is I think for a brief period during the
development we had a capability in our code to configure the watchdog to
use an I/O APIC input; that would be INTIN2 in this scenario.]
* When the native route of IRQ0 via INTIN0 fails for whatever reason -- as
it happens with the system considered here. In this scenario the timer
pulse is delivered through the 8259A to LINT0 input of the local APIC of
the bootstrap processor, quite similarly to how is done for the watchdog
described above. The result is, again, INTIN2 receives these pulses
too. Rafael's system used to escape this scenario, because an incorrect
IRQ0 override would occupy INTIN2 and prevent it from being unmasked.
My conclusion is IRQ2 should be excluded from configuration in all the
cases and the current exception for ACPI systems should be lifted. The
reason being the exception not only being useless, but harmful as well.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Unlike the 32-bit one, the 64-bit variation of the LVT0 setup code for
the "8259A Virtual Wire" through the local APIC timer configuration does
not fully configure the relevant irq_chip structure. Instead it relies on
the preceding I/O APIC code to have set it up, which does not happen if
the I/O APIC variants have not been tried.
The patch includes corresponding changes to the 32-bit variation too
which make them both the same, barring a small syntactic difference
involving sequence of functions in the source. That should work as an aid
with the upcoming merge.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
IRQ0 is edge-triggered, but the "8259A Virtual Wire" through the local
APIC configuration in the 32-bit version uses the "fasteoi" handler
suitable for level-triggered APIC interrupt. Rewrite code so that the
"edge" handler is used. The 64-bit version uses different code and is
unaffected.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
In dwarf2_32.h, test for CONFIG_AS_CFI instead of
CONFIG_UNWIND_INFO. Turns out that searching for UNWIND_INFO
returns no match in any Kconfig or Makefile, so we're really
just throwing everything away regarding dwarf frames for i386.
The test that generates CONFIG_AS_CFI does not have anything
x86_64-specific, and right now, checking V=1 builds shows me
that the flags is there anyway, although unused.
Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
In dwarf_64.h header, use the "ignore" macro the way
i386 does.
Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The RING0_INT_FRAME macro defines a CFI_STARTPROC.
So we should really be using CFI_ENDPROC after it.
Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Currently, ipr does not support HDIO_GET_IDENTITY to SATA devices.
An oops occurs if userspace attempts to send the command. Since hald
issues the command, ensure we fail the ioctl in ipr. This is a
temporary solution to the oops. Once the ipr libata EH conversion
is upstream, ipr will fully support HDIO_GET_IDENTITY.
Tested-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev:
libata-acpi: don't call sleeping function from invalid context
Added Targa Visionary 1000 IDE adapter to pata_sis.c
libata-acpi: filter out DIPM enable
When we release the iclog, we do an atomic_dec_and_lock to determine if
we are the last reference and need to trigger update of log headers and
writeout. However, in xlog_state_get_iclog_space() we also need to
check if we have the last reference count there. If we do, we release
the log buffer, otherwise we decrement the reference count.
But the compare and decrement in xlog_state_get_iclog_space() is not
atomic, so both places can see a reference count of 2 and neither will
release the iclog. That leads to a filesystem hang.
Close the race by replacing the atomic_read() and atomic_dec() pair with
atomic_add_unless() to ensure that they are executed atomically.
Signed-off-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Tim Shimmin <tes@sgi.com>
Tested-by: Eric Sandeen <sandeen@sandeen.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
i spent a fair amount of time chasing a 64-bit bootup crash that manifested
itself as bootup segfaults:
S10network[1825]: segfault at 7f3e2b5d16b8 ip 00000031108748c9 sp 00007fffb9c14c70 error 4 in libc-2.7.so[3110800000+14d000]
eventually causing init to die and panic the system:
Kernel panic - not syncing: Attempted to kill init!
Pid: 1, comm: init Not tainted 2.6.26-rc9-tip #13878
after a maratonic bisection session, the bad commit turned out to be:
| b7675791859075418199c7af86a116ea34eaf5bd is first bad commit
| commit b7675791859075418199c7af86a116ea34eaf5bd
| Author: Jeremy Fitzhardinge <jeremy@goop.org>
| Date: Wed Jun 25 00:19:00 2008 -0400
|
| x86: remove open-coded save/load segment operations
|
| This removes a pile of buggy open-coded implementations of savesegment
| and loadsegment.
after some more bisection of this patch itself, it turns out that what
makes the difference are the savesegment() changes to __switch_to().
Taking a look at this portion of arch/x86/kernel/process_64.o revealed
this crutial difference:
| good: 99c: 8c e0 mov %fs,%eax
| 99e: 89 45 cc mov %eax,-0x34(%rbp)
|
| bad: 99c: 8c 65 cc mov %fs,-0x34(%rbp)
which is due to:
| unsigned fsindex;
| - asm volatile("movl %%fs,%0" : "=r" (fsindex));
| + savesegment(fs, fsindex);
savesegment() is implemented as:
#define savesegment(seg, value) \
asm("mov %%" #seg ",%0":"=rm" (value) : : "memory")
note the "m" modifier - it allows GCC to generate the segment move
into a memory operand as well.
But regarding segment operands there's a subtle detail in the x86
instruction set: the above 16-bit moves are zero-extend, but only
if it goes to a register.
If it goes to a memory operand, -0x34(%rbp) in the above case, there's
no zero-extend to 32-bit and the instruction will only save 16 bits
instead of the intended 32-bit.
The other 16 bits is random data - which can cause problems when that
value is used later on.
The solution is to only allow segment operands to go to registers.
This fix allows my test-system to boot up without crashing.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
fix:
kernel/trace/ftrace.c:1615: error: 'ftraced_suspend' undeclared (first use in this function)
kernel/trace/ftrace.c:1615: error: (Each undeclared identifier is reported only once
kernel/trace/ftrace.c:1615: error: for each function it appears in.)
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The sched_clock code currently tries to keep all CPU clocks of all CPUS
somewhat in sync. At every clock tick it records the gtod clock and
uses that and jiffies and the TSC to calculate a CPU clock that tries to
stay in sync with all the other CPUs.
ftrace depends heavily on this timer and it detects when this timer
"jumps". One problem is that the TSC and the gtod also drift.
When the TSC is 0.1% faster or slower than the gtod it is very noticeable
in ftrace. To help compensate for this, I've added a multiplier that
tries to keep the CPU clock updating at the same rate as the gtod.
I've tried various ways to get it to be in sync and this ended up being
the most reliable. At every scheduler tick we calculate the new multiplier:
multi = delta_gtod / delta_TSC
This means we perform a 64 bit divide at the tick (once a HZ). A shift
is used to handle the accuracy.
Other methods that failed due to dynamic HZ are:
(not used) multi += (gtod - tsc) / delta_gtod
(not used) multi += (gtod - (last_tsc + delta_tsc)) / delta_gtod
as well as other variants.
This code still allows for a slight drift between TSC and gtod, but
it keeps the damage down to a minimum.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
To read the gtod we need to grab the xtime lock for read. Reading the gtod
before the TSC can cause a bigger gab if the xtime lock is contended.
This patch simply reverses the order to read the TSC after the gtod.
The locking in the reading of the gtod handles any barriers one might
think is needed.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Reading the CPU clock should try to stay accurate within the CPU.
By reading the CPU clock from another CPU and updating the deltas can
cause unneeded jumps when reading from the local CPU.
This patch changes the code to update the last read TSC only when read
from the local CPU.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The algorithm to calculate the 'now' of another CPU is not correct.
At each scheduler tick, each CPU records the last sched_clock and
gtod (tick_raw and tick_gtod respectively). If the TSC is somewhat the
same in speed between two clocks the algorithm would be:
tick_gtod1 + (now1 - tick_raw1) = tick_gtod2 + (now2 - tick_raw2)
To calculate now2 we would have:
now2 = (tick_gtod1 - tick_gtod2) + (tick_raw2 - tick_raw1) + now1
Currently the algorithm is:
now2 = (tick_gtod1 - tick_gtod2) + (tick_raw1 - tick_raw2) + now1
This solves most of the rest of the issues I've had with timestamps in
ftace.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Working with ftrace I would get large jumps of 11 millisecs or more with
the clock tracer. This killed the latencing timings of ftrace and also
caused the irqoff self tests to fail.
What was happening is with NO_HZ the idle would stop the jiffy counter and
before the jiffy counter was updated the sched_clock would have a bad
delta jiffies to compare with the gtod with the maximum.
The jiffies would stop and the last sched_tick would record the last gtod.
On wakeup, the sched clock update would compare the gtod + delta jiffies
(which would be zero) and compare it to the TSC. The TSC would have
correctly (with a stable TSC) moved forward several jiffies. But because the
jiffies has not been updated yet the clock would be prevented from moving
forward because it would appear that the TSC jumped too far ahead.
The clock would then virtually stop, until the jiffies are updated. Then
the next sched clock update would see that the clock was very much behind
since the delta jiffies is now correct. This would then jump the clock
forward by several jiffies.
This caused ftrace to report several milliseconds of interrupts off
latency at every resume from NO_HZ idle.
This patch adds hooks into the nohz code to disable the checking of the
maximum clock update when nohz is in effect. It resumes the max check
when nohz has updated the jiffies again.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
With keeping the max and min sched time within one jiffy of the gtod clock
was too tight. Just before a schedule tick the max could easily be hit, as
well as just after a schedule_tick the min could be hit. This caused the
clock to jump around by a jiffy.
This patch widens the minimum to
last gtod + (delta_jiffies ? delta_jiffies - 1 : 0) * TICK_NSECS
and the maximum to
last gtod + (2 + delta_jiffies) * TICK_NSECS
This keeps the minum to gtod or if one jiffy less than delta jiffies
and the maxim 2 jiffies ahead of gtod. This may cause unstable TSCs to be
a bit more sporadic, but it helps keep a clock with a stable TSC working well.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The sched_clock code tries to keep within the gtod time by one tick (jiffy).
The current code mistakenly keeps track of the delta jiffies between
updates of the clock, where the the delta is used to compare with the
number of jiffies that have past since an update of the gtod. The gtod is
updated at each schedule tick not each sched_clock update. After one
jiffy passes the clock is updated fine. But the delta is taken from the
last update so if the next update happens before the next tick the delta
jiffies used will be incorrect.
This patch changes the code to check the delta of jiffies between ticks
and not updates to match the comparison of the updates with the gtod.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Currently the function tracer uses the global tracer_enabled variable that
is used to keep track if the tracer is enabled or not. The function tracing
startup needs to be separated out, otherwise the internal happenings of
the tracer startup is also recorded.
This patch creates a ftrace_function_enabled variable to all the starting
of the function traces to happen after everything has been started.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
It has been suggested that I add a way to disable the function tracer
on an oops. This code adds a ftrace_kill_atomic. It is not meant to be
used in normal situations. It will disable the ftrace tracer, but will
not perform the nice shutdown that requires scheduling.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This is more of a clean up. Currently the function tracer initializes the
tracer with which ever CPU was last used for tracing. This value isn't
realy useful for function tracing, but at least it should be something other
than a random number.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Enabling the wakeup tracer before enabling the function tracing causes
some strange results due to the dynamic enabling of the functions.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
There is no CONFIG_PREEMPT_DESKTOP. Use the proper entry CONFIG_PREEMPT.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
After the sched_clock code has been removed from sched.c we can now trace
the scheduler. The scheduler has a lot of functions that would be worth
tracing.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When CONFIG_FTRACE is not enabled, the tracing_start_functon_trace
and tracing_stop_function_trace should be nops.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
We have two markers now that are enabled on sched_switch. One that records
the context switching and the other that records task wake ups. Currently
we enable the tracing first and then set the markers. This causes some
confusing traces:
# tracer: sched_switch
#
# TASK-PID CPU# TIMESTAMP FUNCTION
# | | | | |
trace-cmd-3973 [00] 115.834817: 3973:120:R + 3: 0:S
trace-cmd-3973 [01] 115.834910: 3973:120:R + 6: 0:S
trace-cmd-3973 [02] 115.834910: 3973:120:R + 9: 0:S
trace-cmd-3973 [03] 115.834910: 3973:120:R + 12: 0:S
trace-cmd-3973 [02] 115.834910: 3973:120:R + 9: 0:S
<idle>-0 [02] 115.834910: 0:140:R ==> 3973:120:R
Here we see that trace-cmd with PID 3973 wakes up task 9 but the next line
shows the idle task doing a context switch to task 3973.
Enabling the tracing to _after_ the markers are set creates a much saner
output:
# tracer: sched_switch
#
# TASK-PID CPU# TIMESTAMP FUNCTION
# | | | | |
<idle>-0 [02] 7922.634225: 0:140:R ==> 4790:120:R
trace-cmd-4789 [03] 7922.634225: 0:140:R + 4790:120:R
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Use the X86_FEATURE_SYSENTER32 to remove hard-coded CPU vendor check.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Add pseudo-feature bits to describe whether the CPU supports sysenter
and/or syscall from ia32-compat userspace. This removes a hardcoded
test in vdso32-setup.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The problem is introduced by commit
664d080c41.
acpi_evaluate_integer is a sleeping function,
and it should not be called with spin_lock_irqsave.
https://bugzilla.redhat.com/show_bug.cgi?id=451399
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Some BIOSen enable DIPM via _GTF which causes command timeouts under
certain configuration. This didn't occur on 2.6.25 because 2.6.25
defaulted to SRST, so _GTF wasn't executed during boot probe, so ahci
host reset disabled DIPM and as _GTF wasn't executed after SRST, DIPM
wasn't enabled. On 2.6.26, hardreset is used during probe and after
probe _GTF is executed enabling DIPM and thus the failures.
This patch could theoretically disable DIPM on machines which used to
have it enabled on 2.6.25 but AFAIK ahci is currently the only driver
which uses SATA ACPI hierarchy (_SDD) and as the host reset would have
always disabled DIPM, this shouldn't happen.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Yinghai Lu reported crashes on 64-bit x86:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
IP: [<ffffffff80253b17>] hrtick_start_fair+0x89/0x173
[...]
And with a long session of debugging and a lot of difficulty, tracked it down
to this commit:
--------------->
8fbbc4b45c is first bad commit
commit 8fbbc4b45c
Author: Alok Kataria <akataria@vmware.com>
Date: Tue Jul 1 11:43:34 2008 -0700
x86: merge tsc_init and clocksource code
<--------------
The problem is that the TSC unification missed these Makefile rules
in arch/x86/kernel/Makefile:
# Do not profile debug and lowlevel utilities
CFLAGS_REMOVE_tsc_64.o = -pg
CFLAGS_REMOVE_tsc_32.o = -pg
...
CFLAGS_tsc_64.o := $(nostackp)
...
which rules make sure that various instrumentation and debugging
facilities are disabled for code that might end up in a VDSO - such as
the TSC code.
Reported-and-bisected-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Conflicts:
Signed-off-by: Ingo Molnar <mingo@elte.hu>
when more than 4g memory is installed, don't map the big hole below 4g.
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
save the SLIT, in case we are using fixmap to read it, and that fixmap
could be cleared by others.
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
also let mem= to print out modified e820 map too
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Bernhard Walle <bwalle@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The IRQ rate reported back by the RTC is incorrect when HPET is enabled.
Newer hardware that has HPET to emulate the legacy RTC device gets this value
wrong since after it sets the rate, it returns before setting the variable
used to report the IRQ rate back to users of the device -- so the set rate and
the reported rate get out of sync.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Brownell <david-b@pacbell.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (27 commits)
tun: Persistent devices can get stuck in xoff state
xfrm: Add a XFRM_STATE_AF_UNSPEC flag to xfrm_usersa_info
ipv6: missed namespace context in ipv6_rthdr_rcv
netlabel: netlink_unicast calls kfree_skb on error path by itself
ipv4: fib_trie: Fix lookup error return
tcp: correct kcalloc usage
ip: sysctl documentation cleanup
Documentation: clarify tcp_{r,w}mem sysctl docs
netfilter: nf_nat_snmp_basic: fix a range check in NAT for SNMP
netfilter: nf_conntrack_tcp: fix endless loop
libertas: fix memory alignment problems on the blackfin
zd1211rw: stop beacons on remove_interface
rt2x00: Disable synchronization during initialization
rc80211_pid: Fix fast_start parameter handling
sctp: Add documentation for sctp sysctl variable
ipv6: fix race between ipv6_del_addr and DAD timer
irda: Fix netlink error path return value
irda: New device ID for nsc-ircc
irda: via-ircc proper dma freeing
sctp: Mark the tsn as received after all allocations finish
...
The scenario goes like this. App stops reading from tun/tap.
TX queue gets full and driver does netif_stop_queue().
App closes fd and TX queue gets flushed as part of the cleanup.
Next time the app opens tun/tap and starts reading from it but
the xoff state is not cleared. We're stuck.
Normally xoff state is cleared when netdev is brought up. But
in the case of persistent devices this happens only during
initial setup.
The fix is trivial. If device is already up when an app opens
it we clear xoff state and that gets things moving again.
Signed-off-by: Max Krasnyansky <maxk@qualcomm.com>
Tested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add a XFRM_STATE_AF_UNSPEC flag to handle the AF_UNSPEC behavior for
the selector family. Userspace applications can set this flag to leave
the selector family of the xfrm_state unspecified. This can be used
to to handle inter family tunnels if the selector is not set from
userspace.
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Roland McGrath