On Mon, Apr 15, 2013 at 12:35:52PM -0400, Vivek Goyal wrote:
[..]
> > My first guess would be that mmap_sem is held during exec, so you
> > can't have __mm_populate() try holding it recursively.
>
> I think it is not mmap_sem as even with VM_LOCKED, we take mmap_sem
> and things are fine.
>
> So things work till 3.8 and break in 3.8-rc1 (with both VM_LOCKED and
> VM_POPULATE specifed). I will do git bisect and try to figure out which
> is first commit which has the issue.
Ok, following seems to be first bad commit.
commit bebeb3d68b24bb4132d452c5707fe321208bcbcd
Author: Michel Lespinasse <wal...@google.com>
Date: Fri Feb 22 16:32:37 2013 -0800
mm: introduce mm_populate() for populating new vmas
I have locked down /sbin/kexec. And I get following traceback after a while.
Thanks
Vivek
[ 93.130001] INFO: rcu_sched self-detected stall on CPU[ 93.131007]
INFO: rcu_sched detected stalls on CPUs/tasks: { 2} (detected by 3,
t=60002 jiffies, g=2786, c=2785, q=10480)
[ 93.131016] Task dump for CPU 2:
[ 93.131018] kexec R running task 0 4861 2982
0x00000088
[ 93.131022] ffff88013252bc68 ffffffff8109ab12 00000000ffffffff
0000000000000000
[ 93.131026] ffff88013252bc58 ffff88013a43c180 ffffffff81881edc
00007feed583221a
[ 93.131028] 00007feed5832000 0000000000000000 ffff88013a43c828
ffff88013a43c180
[ 93.131032] Call Trace:
[ 93.131032] [<ffffffff8109ab12>] ? mark_held_locks+0x82/0x130
[ 93.131040] [<ffffffff81881edc>] ? retint_restore_args+0xe/0xe
[ 93.131045] [<ffffffff8109ab12>] ? mark_held_locks+0x82/0x130
[ 93.131047] [<ffffffff81881edc>] ? retint_restore_args+0xe/0xe
[ 93.131049] [<ffffffff8109acc5>] ?
trace_hardirqs_on_caller+0x105/0x190
[ 93.131051] [<ffffffff8132913e>] ? trace_hardirqs_on_thunk+0x3a/0x3f
[ 93.131055] [<ffffffff81881edc>] ? retint_restore_args+0xe/0xe
[ 93.131058] [<ffffffff81127898>] ? __get_user_pages+0x1d8/0x540
[ 93.131061] [<ffffffff81129fb7>] ? __mlock_vma_pages_range+0x67/0x70
[ 93.131064] [<ffffffff8112a721>] ? __mm_populate+0x71/0x150
[ 93.131066] [<ffffffff8111d01f>] ? vm_mmap_pgoff+0xdf/0xf0
[ 93.131071] [<ffffffff8112c839>] ? sys_mmap_pgoff+0xa9/0x180
[ 93.131073] [<ffffffff8109acc5>] ?
trace_hardirqs_on_caller+0x105/0x190
[ 93.131076] [<ffffffff8132913e>] ? trace_hardirqs_on_thunk+0x3a/0x3f
[ 93.131078] [<ffffffff81006972>] ? sys_mmap+0x22/0x30
[ 93.131081] [<ffffffff8188a342>] ? system_call_fastpath+0x16/0x1b
[ 93.130001] { 2} (t=60153 jiffies g=2786 c=2785 q=10480)
[ 93.130001] Pid: 4861, comm: kexec Not tainted 3.8.0+ #270
[ 93.130001] Call Trace:
[ 93.130001] <IRQ> [<ffffffff810ce69a>]
rcu_check_callbacks+0x21a/0x760
[ 93.130001] [<ffffffff810d22ec>] ? acct_account_cputime+0x1c/0x20
[ 93.130001] [<ffffffff81077570>] ? account_system_time+0x160/0x230
[ 93.130001] [<ffffffff8104f388>] update_process_times+0x48/0x80
[ 93.130001] [<ffffffff810934ad>] tick_sched_handle+0x3d/0x50
[ 93.130001] [<ffffffff810936b5>] tick_sched_timer+0x45/0x70
[ 93.130001] [<ffffffff81067661>] __run_hrtimer+0x81/0x220
[ 93.130001] [<ffffffff81093670>] ? tick_nohz_handler+0xa0/0xa0
[ 93.130001] [<ffffffff8108ce7c>] ? ktime_get_update_offsets+0x4c/0xd0
[ 93.130001] [<ffffffff81067fb7>] hrtimer_interrupt+0xf7/0x250
[ 93.130001] [<ffffffff8188bdb9>] smp_apic_timer_interrupt+0x69/0x99
[ 93.130001] [<ffffffff8188af6f>] apic_timer_interrupt+0x6f/0x80
[ 93.130001] <EOI> [<ffffffff81881edc>] ? retint_restore_args+0xe/0xe
[ 93.130001] [<ffffffff81127898>] ? __get_user_pages+0x1d8/0x540
[ 93.130001] [<ffffffff81129fb7>] __mlock_vma_pages_range+0x67/0x70
[ 93.130001] [<ffffffff8112a721>] __mm_populate+0x71/0x150
[ 93.130001] [<ffffffff8111d01f>] vm_mmap_pgoff+0xdf/0xf0
[ 93.130001] [<ffffffff8112c839>] sys_mmap_pgoff+0xa9/0x180
[ 93.130001] [<ffffffff8109acc5>] ?
trace_hardirqs_on_caller+0x105/0x190
[ 93.130001] [<ffffffff8132913e>] ? trace_hardirqs_on_thunk+0x3a/0x3f
[ 93.130001] [<ffffffff81006972>] sys_mmap+0x22/0x30
[ 93.130001] [<ffffffff8188a342>] system_call_fastpath+0x16/0x1b
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