Andrey Vagin 20afc60f89 x86, perf: Check that current->mm is alive before getting user callchain ... An event may occur when an mm is already released. I added an event in dequeue_entity() and caught a panic with the following backtrace: [ 434.421110] BUG: unable to handle kernel NULL pointer dereference at 0000000000000050 [ 434.421258] IP: [<ffffffff810464ac>] __get_user_pages_fast+0x9c/0x120 ... [ 434.421258] Call Trace: [ 434.421258] [<ffffffff8101ae81>] copy_from_user_nmi+0x51/0xf0 [ 434.421258] [<ffffffff8109a0d5>] ? sched_clock_local+0x25/0x90 [ 434.421258] [<ffffffff8101b048>] perf_callchain_user+0x128/0x170 [ 434.421258] [<ffffffff811154cd>] ? __perf_event_header__init_id+0xed/0x100 [ 434.421258] [<ffffffff81116690>] perf_prepare_sample+0x200/0x280 [ 434.421258] [<ffffffff81118da8>] __perf_event_overflow+0x1b8/0x290 [ 434.421258] [<ffffffff81065240>] ? tg_shares_up+0x0/0x670 [ 434.421258] [<ffffffff8104fe1a>] ? walk_tg_tree+0x6a/0xb0 [ 434.421258] [<ffffffff81118f44>] perf_swevent_overflow+0xc4/0xf0 [ 434.421258] [<ffffffff81119150>] do_perf_sw_event+0x1e0/0x250 [ 434.421258] [<ffffffff81119204>] perf_tp_event+0x44/0x70 [ 434.421258] [<ffffffff8105701f>] ftrace_profile_sched_block+0xdf/0x110 [ 434.421258] [<ffffffff8106121d>] dequeue_entity+0x2ad/0x2d0 [ 434.421258] [<ffffffff810614ec>] dequeue_task_fair+0x1c/0x60 [ 434.421258] [<ffffffff8105818a>] dequeue_task+0x9a/0xb0 [ 434.421258] [<ffffffff810581e2>] deactivate_task+0x42/0xe0 [ 434.421258] [<ffffffff814bc019>] thread_return+0x191/0x808 [ 434.421258] [<ffffffff81098a44>] ? switch_task_namespaces+0x24/0x60 [ 434.421258] [<ffffffff8106f4c4>] do_exit+0x464/0x910 [ 434.421258] [<ffffffff8106f9c8>] do_group_exit+0x58/0xd0 [ 434.421258] [<ffffffff8106fa57>] sys_exit_group+0x17/0x20 [ 434.421258] [<ffffffff8100b202>] system_call_fastpath+0x16/0x1b Signed-off-by: Andrey Vagin <avagin@openvz.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: stable@kernel.org Link: http://lkml.kernel.org/r/1314693156-24131-1-git-send-email-avagin@openvz.org Signed-off-by: Ingo Molnar <mingo@elte.hu>		2011-08-31 15:56:31 +02:00
..
acpi
apic	x86, UV: Remove UV delay in starting slave cpus	2011-08-05 23:48:34 +02:00
cpu	x86, perf: Check that current->mm is alive before getting user callchain	2011-08-31 15:56:31 +02:00
.gitignore
alternative.c
amd_gart_64.c
amd_nb.c
apb_timer.c
aperture_64.c
apm_32.c
asm-offsets_32.c
asm-offsets_64.c
asm-offsets.c
audit_64.c
bootflag.c
check.c
cpuid.c
crash_dump_32.c
crash_dump_64.c
crash.c
devicetree.c
doublefault_32.c
dumpstack_32.c
dumpstack_64.c
dumpstack.c
e820.c
early_printk.c
early-quirks.c
entry_32.S	x86-32: Fix boot with CONFIG_X86_INVD_BUG	2011-08-25 13:27:14 -07:00
entry_64.S	Merge branch 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-tip	2011-08-12 20:46:24 -07:00
ftrace.c
head32.c
head64.c
head_32.S
head_64.S
head.c
hpet.c
hw_breakpoint.c
i386_ksyms_32.c
i387.c
i8237.c
i8253.c
i8259.c
init_task.c
io_delay.c
ioport.c
irq_32.c
irq_64.c
irq_work.c
irq.c
irqinit.c
jump_label.c
kdebugfs.c
kgdb.c
kprobes.c
kvm.c
kvmclock.c
ldt.c
machine_kexec_32.c
machine_kexec_64.c
Makefile	Merge branch 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-tip	2011-08-12 20:46:24 -07:00
mca_32.c
microcode_amd.c
microcode_core.c
microcode_intel.c
mmconf-fam10h_64.c
module.c
mpparse.c
msr.c
paravirt_patch_32.c
paravirt_patch_64.c
paravirt-spinlocks.c
paravirt.c	Merge branch 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-tip	2011-08-12 20:46:24 -07:00
pci-calgary_64.c
pci-dma.c
pci-iommu_table.c
pci-nommu.c
pci-swiotlb.c
pcspeaker.c
probe_roms.c
process_32.c
process_64.c
process.c
ptrace.c
pvclock.c
quirks.c
reboot_32.S
reboot_fixups_32.c
reboot.c
relocate_kernel_32.S
relocate_kernel_64.S
resource.c
rtc.c
setup_percpu.c
setup.c
signal.c
smp.c
smpboot.c
stacktrace.c
step.c	x86-64: Add user_64bit_mode paravirt op	2011-08-04 16:13:49 -07:00
sys_i386_32.c
sys_x86_64.c
syscall_64.c
syscall_table_32.S	All Arch: remove linkage for sys_nfsservctl system call	2011-08-26 15:09:58 -07:00
tboot.c
tce_64.c
test_nx.c
test_rodata.c
time.c
tls.c
tls.h
topology.c
trampoline_32.S
trampoline_64.S
trampoline.c
traps.c	Merge branch 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-tip	2011-08-12 20:46:24 -07:00
tsc_sync.c
tsc.c
verify_cpu.S
vm86_32.c
vmlinux.lds.S	x86-64: Rework vsyscall emulation and add vsyscall= parameter	2011-08-10 19:26:46 -05:00
vsmp_64.c
vsyscall_64.c	x86-64: Rework vsyscall emulation and add vsyscall= parameter	2011-08-10 19:26:46 -05:00
vsyscall_emu_64.S	x86-64: Rework vsyscall emulation and add vsyscall= parameter	2011-08-10 19:26:46 -05:00
vsyscall_trace.h	x86-64: Add vsyscall:emulate_vsyscall trace event	2011-08-04 16:13:53 -07:00
x86_init.c
x8664_ksyms_64.c
xsave.c