Re: [next] next-20220412: BUG: Bad page map in process oom_reaper pte

[Naresh Kamboju]

Hi Andrew and Mike,

On Wed, 13 Apr 2022 at 02:34, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> On Tue, 12 Apr 2022 17:56:42 +0530 Naresh Kamboju <naresh.kamboju@xxxxxxxxxx> wrote:
>
> > Linux next-20220412 i386 LTP mm test case caused following kernel crash
> > however, test runs to complete successfully.

<trim>

> > [  952.018368] BUG: Bad page map in process oom_reaper  pte:06e7703e
> > pmd:0583f067
> >
> >
> > Reported-by: Linux Kernel Functional Testing <lkft@xxxxxxxxxx>
>
> I wonder if this could be 859a85ddf90e714092de again.  But the timing
> seems wrong.
>
> It seems repeatable.  Is it possible to run a bisection search please?

Thanks for looking into this issue.
Allow us sometime I will schedule this bisection and get back to you
with my findings soon. By running LTP CVE test case  "ioctl_sg01"
we are able to reproduce this problem [1] on qemu_i386.

- Naresh

[1] https://lkft.validation.linaro.org/scheduler/job/4876493#L29410
--
Crash log:
tst_test.c:1433: TINFO: Timeout per run is 0h 05m 00s
ioctl_sg01.c:81: TINFO: Found SCSI device /dev/sg1
[ 1135.167555] __swap_info_get: Bad swap file entry 6c009400
[ 1135.168577] BUG: Bad page map in process ioctl_sg01  pte:0128003e
pmd:06bfb067
[ 1135.169694] addr:289e2000 vm_flags:00100073 anon_vma:c2e29b28
mapping:00000000 index:289e2
[ 1135.171357] file:(null) fault:0x0 mmap:0x0 readpage:0x0
[ 1135.172381] CPU: 2 PID: 31128 Comm: ioctl_sg01 Tainted: G        W
       5.18.0-rc1-next-20220411 #1
[ 1135.173914] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS 1.12.0-1 04/01/2014
[ 1135.175263] Call Trace:
[ 1135.175662]  dump_stack_lvl+0x44/0x57
[ 1135.176274]  dump_stack+0xd/0x10
[ 1135.176785]  print_bad_pte.cold+0x82/0xd9
[ 1135.177407]  ? free_swap_and_cache+0x2e/0xe0
[ 1135.178138]  unmap_page_range+0x6b5/0x790
[ 1135.178833]  unmap_single_vma+0x6c/0xd0
[ 1135.179448]  unmap_vmas+0x71/0xe0
[ 1135.179997]  unmap_region+0x88/0xf0
[ 1135.180587]  __do_munmap+0x184/0x3f0
[ 1135.181162]  __vm_munmap+0x71/0x120
[ 1135.181750]  __ia32_sys_munmap+0x17/0x20
[ 1135.182358]  __do_fast_syscall_32+0x4c/0xc0
[ 1135.183086]  do_fast_syscall_32+0x32/0x70
[ 1135.183746]  do_SYSENTER_32+0x15/0x20
[ 1135.184317]  entry_SYSENTER_32+0x98/0xf1
[ 1135.184960] EIP: 0xb7f01549
[ 1135.185407] Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01
10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f
34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d 76 00 58 b8 77 00 00 00 cd 80 90
8d 76
[ 1135.188401] EAX: ffffffda EBX: 27d23000 ECX: 01000000 EDX: 27d23000
[ 1135.189405] ESI: 01000000 EDI: 000000a0 EBP: 09db9520 ESP: bfe3630c
[ 1135.190402] DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 007b EFLAGS: 00000296
[ 1135.191558] Disabling lock debugging due to kernel taint
[ 1135.192604] __swap_info_get: Bad swap file entry 6c009401
[ 1135.193685] BUG: Bad page map in process ioctl_sg01  pte:0128023e
pmd:06bfb067
[ 1135.195104] addr:289e3000 vm_flags:00100073 anon_vma:c2e29b28
mapping:00000000 index:289e3
[ 1135.196640] file:(null) fault:0x0 mmap:0x0 readpage:0x0
[ 1135.197489] CPU: 2 PID: 31128 Comm: ioctl_sg01 Tainted: G    B   W
       5.18.0-rc1-next-20220411 #1