Lockdep reports the warning below when Li tries to offline one cpu:
[ 110.835487] =================================
[ 110.835616] [ INFO: inconsistent lock state ]
[ 110.835688] 2.6.30-rc4-00336-g8c9ed89 #52
[ 110.835757] ---------------------------------
[ 110.835828] inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage.
[ 110.835908] swapper/0 [HC1[1]:SC0[0]:HE0:SE1] takes:
[ 110.835982] (cmci_discover_lock){?.+...}, at: [<ffffffff80236dc0>] cmci_clear+0x30/0x9b
cmci_clear() can be called via smp_call_function_single().
It is better to disable interrupt while holding cmci_discover_lock,
to turn it into an irq-safe lock - we can deadlock otherwise.
[ Impact: fix possible deadlock in the MCE code ]
Reported-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <4A03ED38.8000700@jp.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Reported-by: Shaohua Li<shaohua.li@intel.com>
The Xen pagetables are no longer implicitly reserved as part of the other
i386_start_kernel reservations, so make sure we explicitly reserve them.
This prevents them from being released into the general kernel free page
pool and reused.
[ Impact: fix Xen guest crash ]
Also-Bisected-by: Bryan Donlan <bdonlan@gmail.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Xen-devel <xen-devel@lists.xensource.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <4A032EEC.30509@goop.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Tim Starling reported that crashdump will panic with kernel compiled
with CONFIG_KEXEC_JUMP due to null pointer deference in
machine_kexec_32.c: machine_kexec(), when deferencing
kexec_image. Refering to:
http://bugzilla.kernel.org/show_bug.cgi?id=13265
This patch fixes the BUG via replacing global variable reference:
kexec_image in machine_kexec() with local variable reference: image,
which is more appropriate, and will not be null.
Same BUG is in machine_kexec_64.c too, so fixed too in the same way.
[ Impact: fix crash on kexec ]
Reported-by: Tim Starling <tstarling@wikimedia.org>
Signed-off-by: Huang Ying <ying.huang@intel.com>
LKML-Reference: <1241751101.6259.85.camel@yhuang-dev.sh.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
With the introduction of the .brk section, special care must be taken
that no unused page table entries remain if _brk_end and _end are
separated by a 2M page boundary. cleanup_highmap() runs very early and
hence cannot take care of that, hence potential entries needing to be
removed past _brk_end must be cleared once the brk allocator has done
its job.
[ Impact: avoids undesirable TLB aliases ]
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
If the first non-reserved (sub-)range doesn't fit the size requested,
an endless loop will be entered. If a range returned from
find_e820_area_size() turns out insufficient in size, the range must
be skipped before calling the function again.
[ Impact: fixes boot hang on some platforms ]
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
The mem= option will truncate the memory map at a specified address so
it's not possible to register nodes with memory beyond the e820 upper
bound.
unparse_node() is only called when then node had memory associated with
it, although with the mem= option it is no longer addressable.
[ Impact: fix boot hang on certain (large) systems ]
Reported-by: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: Jack Steiner <steiner@sgi.com>
LKML-Reference: <alpine.DEB.2.00.0905051248150.20021@chino.kir.corp.google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
tracing: x86, mmiotrace: fix range test
tracing: fix ref count in splice pages
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86: show number of core_siblings instead of thread_siblings in /proc/cpuinfo
amd-iommu: fix iommu flag masks
x86: initialize io_bitmap_base on 32bit
x86: gettimeofday() vDSO: fix segfault when tv == NULL
Commit 7ad728f981
(cpumask: x86: convert cpu_sibling_map/cpu_core_map to cpumask_var_t)
changed the output of /proc/cpuinfo for siblings:
Example on an AMD Phenom:
physical id : 0
siblings : 1
core id : 3
cpu cores : 4
Before that commit it was:
physical id : 0
siblings : 4
core id : 3
cpu cores : 4
Instead of cpu_core_mask it now uses cpu_sibling_mask to count siblings.
This is due to the following hunk of above commit:
| --- a/arch/x86/kernel/cpu/proc.c
| +++ b/arch/x86/kernel/cpu/proc.c
| @@ -14,7 +14,7 @@ static void show_cpuinfo_core(struct seq_file *m, struct cpuinf
| if (c->x86_max_cores * smp_num_siblings > 1) {
| seq_printf(m, "physical id\t: %d\n", c->phys_proc_id);
| seq_printf(m, "siblings\t: %d\n",
| - cpus_weight(per_cpu(cpu_core_map, cpu)));
| + cpumask_weight(cpu_sibling_mask(cpu)));
| seq_printf(m, "core id\t\t: %d\n", c->cpu_core_id);
| seq_printf(m, "cpu cores\t: %d\n", c->booted_cores);
| seq_printf(m, "apicid\t\t: %d\n", c->apicid);
This was a mistake, because the impact line shows that this side-effect
was not anticipated:
Impact: reduce per-cpu size for CONFIG_CPUMASK_OFFSTACK=y
So revert the respective hunk to restore the old behavior.
[ Impact: fix sibling-info regression in /proc/cpuinfo ]
Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
LKML-Reference: <20090504182859.GA29045@alberich.amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The feature bits should be set via bitmasks, not via feature IDs.
[ Impact: fix feature enabling in newer IOMMU versions ]
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
LKML-Reference: <20090504102028.GA30307@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'x86-mce-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-tip:
x86, mce: fix boot logging logic
x86, mce: make polling timer interval per CPU
commit db949bba3c (x86-32: use non-lazy
io bitmap context switching) broke ioperm for 32bit because it removed
the lazy initialization of io_bitmap_base and did not set it to the
real bitmap offset.
[ Impact: fix non-working sys_ioperm() on 32-bit kernels ]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
According to the gettimeofday(2) manual:
If either tv or tz is NULL, the corresponding structure is not
set or returned.
Since it is legal to give NULL as the tv argument, the code should make
sure tv is not NULL before trying to dereference it.
This issue manifests itself on x86_64 when vdso=0 is not on the kernel
command-line and libc uses the vDSO for gettimeofday() (e.g. glibc >=
2.7). A simple reproducer:
#include <stdio.h>
#include <sys/time.h>
int main(void)
{
struct timezone tz;
gettimeofday(NULL, &tz);
return 0;
}
See http://bugs.debian.org/466491 for more details.
[ Impact: fix gettimeofday(NULL, &tz) segfault ]
Signed-off-by: John Wright <john.wright@hp.com>
Cc: Andi Kleen <ak@suse.de>
Cc: John Wright <john.wright@hp.com>
LKML-Reference: <1241037121-14805-1-git-send-email-john.wright@hp.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6:
PCI: only save/restore existent registers in the PCIe capability
x86/PCI: don't bother with root quirks if _CRS is used
docbooks: add/fix PCI kernel-doc
PCI: cleanup debug output resources
x86/PCI: set_pci_bus_resources_arch_default cleanups
x86/PCI: Move set_pci_bus_resources_arch_default into arch/x86
x86/PCI: don't call e820_all_mapped with -1 in the mmconfig case
PCI quirk: disable MSI on VIA VT3364 chipsets
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, hpet: Stop soliciting hpet=force users on ICH4M
x86: check boundary in setup_node_bootmem()
uv_time: add parameter to uv_read_rtc()
x86: hpet: fix periodic mode programming on AMD 81xx
x86: more than 8 32-bit CPUs requires X86_BIGSMP
x86: avoid theoretical spurious NMI backtraces with CONFIG_CPUMASK_OFFSTACK=y
x86: fix boot crash in NMI watchdog with CONFIG_CPUMASK_OFFSTACK=y and flat APIC
x86-64: fix FPU corruption with signals and preemption
x86/uv: fix for no memory at paddr 0
docs, x86: add nox2apic back to kernel-parameters.txt
x86: mm/numa_32.c calculate_numa_remap_pages should use __init
x86, kbuild: make "make install" not depend on vmlinux
x86/uv: fix init of cpu-less nodes
x86/uv: fix init of memory-less nodes
* 'irq-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86/irq: mark NUMA_MIGRATE_IRQ_DESC broken
x86, irq: Remove IRQ_DISABLED check in process context IRQ move
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6: (34 commits)
ACPI, i915: Register ACPI video even when not modesetting
Revert "ACPICA: delete check for AML access to port 0x81-83"
I/O port protection: update for windows compatibility.
sony-laptop: always try to unblock rfkill on load
sony-laptop: fix bogus error message display on resume
ACPI: EC: Fix ACPI EC resume non-query interrupt message
sony-laptop: SNC input event 38 fix
sony-laptop: SNC 127 Initialization Fix
sony-laptop: Duplicate SNC 127 Event Fix
ACPI: prevent processor.max_cstate=0 boot crash
ACPI/hpet: prevent boot hang when hpet=force used on ICH-4M
ACPI: delete obsolete "bus master activity" proc field
ACPI: idle: mark_tsc_unstable() at init-time, not run-time
ACPI: add /sys/firmware/acpi/interrupts/sci_not counter
ACPI video: fix an error when the brightness levels on AC and on Battery are same
acpi-cpufreq: Do not let get_measured perf depend on internal variable
acpi-cpufreq: style-only: add parens to math expression
acpi-cpufreq: Cleanup: Use printk_once
x86, acpi_cpufreq: Fix the NULL pointer dereference in get_measured_perf
thinkpad-acpi: bump up version to 0.23
...
The HPET in the ICH4M is not documented in the data sheet
because it was not officially validated.
While it is fine for hackers to continue to use "hpet=force"
to enable the hardware that they have, it is not prudent to
solicit additional "hpet=force" users on this hardware.
[ Impact: remove hpet=force syslog message on old-ICH systems ]
Signed-off-by: Len Brown <len.brown@intel.com>
Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
LKML-Reference: <alpine.LFD.2.00.0904231918510.15843@localhost.localdomain>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Commit dc09855 ("x86/uv: fix init of memory-less nodes") causes a
two sockets system (where node-1 doesn't have RAM installed) to crash.
That commit makes node_possible include cpu nodes that do not have memory.
So check boundary in setup_node_bootmem().
[ Impact: fix boot crash on RAM-less NUMA node system ]
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Jack Steiner <steiner@sgi.com>
LKML-Reference: <49EF89DF.9090404@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
It will be overwriten later if _CRS is used, so don't bother to set it.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Rename set_pci_bus_resources_arch_default to x86_pci_root_bus_res_quirks, move
the weak version from common.c to i386.c, and before calling, make sure it's a
root bus.
Reviewed-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Commit 30a18d6c3f introduced a new
function to set the PCI bus resources. Unfortunately, neither the
author, nor the committers seemed to know that we already have somewhere
to do that -- pcibios_fixup_bus(). This patch moves the hook (used only
by the K8 code) into x86-specific code where it should have been in the
first place.
Cc: Yinghai Lu <yinghai.lu@sun.com>
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
The earlier patch to change the poller to a separate function subtly
broke the boot logging logic. This could lead to machine checks
getting logged at boot even when disabled or defaulting to off
on some systems. Fix that.
[ Impact: bug fix - avoid spurious MCE in log ]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
The polling timer while running per CPU still uses a global next_interval
variable, which lead to some CPUs either polling too fast or too slow.
This was not a serious problem because all errors get picked up eventually,
but it's still better to avoid it. Turn next_interval into a per cpu variable.
v2: Fix check_interval == 0 case (Hidetoshi Seto)
[ Impact: minor bug fix ]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
uv_read_rtc() is referenced by read member of struct clocksource clocksource_uv.
In include/linux/clocksource.h, read of struct clocksource is declared as:
cycle_t (*read)(struct clocksource *cs)
This got introduced recently in:
8e19608: clocksource: pass clocksource to read() callback
But arch/x86/kernel/uv_time.c was not properly converted by that pach.
This patch adds a dummy parameter (struct clocksource type) to uv_read_rtc() to
fix the incompatible reference in clocksource_uv, and add a NULL parameter in
all places where uv_read_rtc() gets called.
[ Impact: cleanup, address compiler warning ]
Signed-off-by: Coly Li <coly.li@suse.de>
Cc: Dimitri Sivanich <sivanich@sgi.com>
Cc: Magnus Damm <damm@igel.co.jp>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Hugh Dickins <hugh@veritas.com>
LKML-Reference: <49EF3614.1050806@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Dimitri Sivanich <sivanich@sgi.com>
(See http://bugzilla.kernel.org/show_bug.cgi?id=12961)
It partially reverts commit c23e253e67
(x86: hpet: stop HPET_COUNTER when programming periodic mode)
HPET on AMD 81xx chipset needs a second write (with HPET_TN_SETVAL
cleared) to T0_CMP register to set the period in periodic mode.
With this patch HPET_COUNTER is still stopped but not reset when HPET
is programmed in periodic mode. This should help to avoid races when
HPET is programmed in periodic mode and fixes a boot time hang that
I've observed on a machine when using 1000HZ.
[ Impact: fix boot time hang on machines with AMD 81xx chipset ]
Reported-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Tested-by: Jeff Mahoney <jeffm@suse.com>
LKML-Reference: <20090421180037.GA2763@alberich.amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Properly unregister cpufreq notifier on onload if it was registered
during init.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Not releasing the time_page causes a leak of that page or the compound
page it is situated in.
Cc: stable@kernel.org
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
In non-SMP mode, the variable section attribute specified by DECLARE_PER_CPU()
does not agree with that specified by DEFINE_PER_CPU(). This means that
architectures that have a small data section references relative to a base
register may throw up linkage errors due to too great a displacement between
where the base register points and the per-CPU variable.
On FRV, the .h declaration says that the variable is in the .sdata section, but
the .c definition says it's actually in the .data section. The linker throws
up the following errors:
kernel/built-in.o: In function `release_task':
kernel/exit.c:78: relocation truncated to fit: R_FRV_GPREL12 against symbol `per_cpu__process_counts' defined in .data section in kernel/built-in.o
kernel/exit.c:78: relocation truncated to fit: R_FRV_GPREL12 against symbol `per_cpu__process_counts' defined in .data section in kernel/built-in.o
To fix this, DECLARE_PER_CPU() should simply apply the same section attribute
as does DEFINE_PER_CPU(). However, this is made slightly more complex by
virtue of the fact that there are several variants on DEFINE, so these need to
be matched by variants on DECLARE.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
$ cat x86-more-than-8-cpus-requires-bigsmp.patch
Enforce NR_CPUS <= 8 limitation if X86_BIGSMP not set
Configuring more than 8 logical CPUs on 32-bit x86 requires
X86_BIGSMP to be set in order to boot successfully, if more than 8
logical CPUs are actually found at boot time. The X86_BIGSMP help
text describes that it is required to be set if more than 8 CPUs
are configured, but this was previously not enforced.
This configuration error has affected multiple distributions:
https://bugzilla.redhat.com/show_bug.cgi?id=480844https://issues.rpath.com/browse/RPL-3022
Signed-off-by: Michael K Johnson <johnsonm@rpath.com>
LKML-Reference: <20090422014448.GB32541@logo.rdu.rpath.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Pass clocksource pointer to the read() callback for clocksources. This
allows us to share the callback between multiple instances.
[hugh@veritas.com: fix powerpc build of clocksource pass clocksource mods]
[akpm@linux-foundation.org: cleanup]
Signed-off-by: Magnus Damm <damm@igel.co.jp>
Acked-by: John Stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In theory (though not shown in practice) alloc_cpumask_var() doesn't zero
memory, so CPUs might print an "NMI backtrace for cpu %d" once on boot.
(Bug introduced in fcef8576d8).
[ Impact: avoid theoretical syslog noise in rare configs ]
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <alpine.DEB.2.00.0904202113520.10097@gandalf.stny.rr.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
fcef8576d8 converted backtrace_mask to a
cpumask_var_t, and assumed check_nmi_watchdog was called before
nmi_watchdog_tick was ever called. Steven's oops shows I was wrong.
This is something of a bandaid: I'm not sure we *should* be calling
nmi_watchdog_tick before check_nmi_watchdog. Note that gcc eliminates
this test for the CONFIG_CPUMASK_OFFSTACK=n case.
[ Impact: fix boot crash in rare configs ]
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
LKML-Reference: <alpine.DEB.2.00.0904202113520.10097@gandalf.stny.rr.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This is a version incorporating Christoph's suggestion.
Separate out common *fstatat functionality into a single function
instead of duplicating it all over the code.
Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
In 64bit signal delivery path, clear_used_math() was happening before saving
the current active FPU state on to the user stack for signal handling. Between
clear_used_math() and the state store on to the user stack, potentially we
can get a page fault for the user address and can block. Infact, while testing
we were hitting the might_fault() in __clear_user() which can do a schedule().
At a later point in time, we will schedule back into this process and
resume the save state (using "xsave/fxsave" instruction) which can lead
to DNA fault. And as used_math was cleared before, we will reinit the FP state
in the DNA fault and continue. This reinit will result in loosing the
FPU state of the process.
Move clear_used_math() to a point after the FPU state has been stored
onto the user stack.
This issue is present from a long time (even before the xsave changes
and the x86 merge). But it can easily be exposed in 2.6.28.x and 2.6.29.x
series because of the __clear_user() in this path, which has an explicit
__cond_resched() leading to a context switch with CONFIG_PREEMPT_VOLUNTARY.
[ Impact: fix FPU state corruption ]
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: <stable@kernel.org> [2.6.28.x, 2.6.29.x]
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Fix endcase where the memory at physical address 0 does not really
exist AND one of the sockets on blade 0 has no active cpus.
The memory that _appears_ to be at physical address 0 is actually
memory that located at a different address but has been remapped by
the chipset so that it appears to be at physical address 0.
When determining the UV pnode, the algorithm for determining the pnode
incorrectly used the relocated physical address instead of the actual
(global) address.
[ Impact: boot failure on partitioned systems ]
Signed-off-by: Jack Steiner <steiner@sgi.com>
LKML-Reference: <20090420132530.GA23156@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Take already available policy->cpuinfo.max_freq and get rid of acpi-cpufreq
specific max_freq variable.
This implies that P0 is always the highest frequency which should always
be true as ACPI spec says:
As a result, the zeroth entry describes the highest performance state
Signed-off-by: Thomas Renninger <trenn@suse.de>
Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Fixes guest crash 'lguest: bad read address 0x4800000 len 256'
The new per-cpu allocator ends up handing a non-linear address to
write_gdt_entry. We do __pa() on it, and hand it to the host, which
kills us.
I've long wanted to make the hypercall "LOAD_GDT_ENTRY" to match the IDT
code, but had no pressing reason until now.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: lguest@ozlabs.org
I hit the check_flags error of lockdep:
WARNING: at kernel/lockdep.c:2893 check_flags+0x1a7/0x1d0()
[...]
hardirqs last enabled at (12567): [<ffffffff8026206a>] local_bh_enable+0xaa/0x110
hardirqs last disabled at (12569): [<ffffffff80610c76>] int3+0x16/0x40
softirqs last enabled at (12566): [<ffffffff80514d2b>] lock_sock_nested+0xfb/0x110
softirqs last disabled at (12568): [<ffffffff8058454e>] tcp_prequeue_process+0x2e/0xa0
The check_flags warning of lockdep tells me that lockdep thought interrupts
were disabled, but they were really enabled.
The numbers in the above parenthesis show the order of events:
12566: softirqs last enabled: lock_sock_nested
12567: hardirqs last enabled: local_bh_enable
12568: softirqs last disabled: tcp_prequeue_process
12566: hardirqs last disabled: int3
int3 is a breakpoint!
Examining this further, I have CONFIG_NET_TCPPROBE enabled which adds
break points into the kernel.
The paranoid_exit of the return of int3 does not account for enabling
interrupts on return to kernel. This code is a bit tricky since it
is also used by the nmi handler (when lockdep is off), and we must be
careful about the swapgs. We can not call kernel code after the swapgs
has been performed.
[ Impact: fix lockdep check_flags warning + self-turn-off ]
Acked-by: Peter Zijlsta <a.p.zijlstra@chello.nl>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Hidetoshi Seto