lkml.org 
[lkml]   [2021]   [Aug]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [mm] f9ce0be71d: BUG:KCSAN:data-race_in_next_uptodate_page/next_uptodate_page
On Thu, Aug 26, 2021 at 10:41:57PM +0800, kernel test robot wrote:
>
>
> Greeting,
>
> FYI, we noticed the following commit (built with clang-14):
>
> commit: f9ce0be71d1fbb038ada15ced83474b0e63f264d ("mm: Cleanup faultaround and finish_fault() codepaths")
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master
>
>
> in testcase: trinity
> version:
> with following parameters:
>
> number: 99999
> group: group-04
>
> test-description: Trinity is a linux system call fuzz tester.
> test-url: http://codemonkey.org.uk/projects/trinity/
>
>
> on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G
>
> caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):
>
>
> +------------------------------------------------------------------------+-----------+------------+
> | | v5.11-rc4 | f9ce0be71d |
> +------------------------------------------------------------------------+-----------+------------+
> | BUG:KCSAN:data-race_in_next_uptodate_page/next_uptodate_page | 0 | 19 |
> | BUG:KCSAN:data-race_in_mark_page_accessed/next_uptodate_page | 0 | 17 |
> | BUG:KCSAN:data-race_in_next_uptodate_page/page_memcg | 0 | 13 |
> | BUG:KCSAN:data-race_in_next_uptodate_page/unlock_page | 0 | 13 |
> +------------------------------------------------------------------------+-----------+------------+
>
>
> If you fix the issue, kindly add following tag
> Reported-by: kernel test robot <oliver.sang@intel.com>
>
>
> [ 184.717904][ T1873] ==================================================================
> [ 184.718938][ T1873] BUG: KCSAN: data-race in next_uptodate_page / unlock_page
> [ 184.719828][ T1873]
> [ 184.720103][ T1873] write (marked) to 0xffffea00050f37c0 of 8 bytes by task 1872 on cpu 1:
> [ 184.721024][ T1873] unlock_page+0x102/0x1b0
> [ 184.721533][ T1873] filemap_map_pages+0x6c6/0x890
> [ 184.722102][ T1873] handle_mm_fault+0x179c/0x27f0
> [ 184.722672][ T1873] do_user_addr_fault+0x3fb/0x830
> [ 184.723263][ T1873] exc_page_fault+0xc3/0x1a0
> [ 184.723845][ T1873] asm_exc_page_fault+0x1e/0x30
> [ 184.724427][ T1873]
> [ 184.724720][ T1873] read to 0xffffea00050f37c0 of 8 bytes by task 1873 on cpu 0:
> [ 184.725575][ T1873] next_uptodate_page+0x456/0x830
> [ 184.726161][ T1873] filemap_map_pages+0x728/0x890
> [ 184.726747][ T1873] handle_mm_fault+0x179c/0x27f0
> [ 184.727332][ T1873] do_user_addr_fault+0x3fb/0x830
> [ 184.727905][ T1873] exc_page_fault+0xc3/0x1a0
> [ 184.728440][ T1873] asm_exc_page_fault+0x1e/0x30
> [ 184.729027][ T1873]
> [ 184.729313][ T1873] Reported by Kernel Concurrency Sanitizer on:
> [ 184.730019][ T1873] CPU: 0 PID: 1873 Comm: systemd-udevd Not tainted 5.11.0-rc4-00001-gf9ce0be71d1f #1
> [ 184.731103][ T1873] ==================================================================

Line annotation would be helpful.

And I'm not very familiar with KCSAN. My guess it reports PageLock() vs.
clearing PG_locked. In this context it looks safe, unless I miss
something.

Do we need some annotation to help KCSAN?

--
Kirill A. Shutemov

\
 
 \ /
  Last update: 2021-08-27 17:43    [W:0.082 / U:0.372 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site