[moderation] [fs?] [mm?] KCSAN: data-race in ondemand_readahead / read_pages (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: c1ca10ceffbb Merge tag 'scsi-fixes' of git://git.kernel.or..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=170e0158180000
kernel config: https://syzkaller.appspot.com/x/.config?x=b4c8befe72e5ccb8
dashboard link: https://syzkaller.appspot.com/bug?extid=d1f97100cda5b6b915f6
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [ak...@linux-foundation.org linux-...@vger.kernel.org linux-...@vger.kernel.org linu...@kvack.org wi...@infradead.org]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a59d894c1c62/disk-c1ca10ce.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/91b15b8ced26/vmlinux-c1ca10ce.xz
kernel image: https://storage.googleapis.com/syzbot-assets/db4279bd95f5/bzImage-c1ca10ce.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d1f971...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in ondemand_readahead / read_pages

read to 0xffff88813fa22784 of 4 bytes by task 21730 on cpu 1:
ondemand_readahead+0x158/0x670 mm/readahead.c:578
page_cache_sync_ra+0x27e/0x2a0 mm/readahead.c:693
page_cache_sync_readahead include/linux/pagemap.h:1300 [inline]
filemap_get_pages+0x251/0xf90 mm/filemap.c:2498
filemap_read+0x214/0x680 mm/filemap.c:2594
generic_file_read_iter+0x78/0x330 mm/filemap.c:2784
ext4_file_read_iter+0x1d8/0x2a0
call_read_iter include/linux/fs.h:2079 [inline]
copy_splice_read+0x39f/0x5d0 fs/splice.c:365
do_splice_read fs/splice.c:984 [inline]
splice_direct_to_actor+0x288/0x660 fs/splice.c:1089
do_splice_direct_actor fs/splice.c:1207 [inline]
do_splice_direct+0xd7/0x150 fs/splice.c:1233
do_sendfile+0x3b9/0x960 fs/read_write.c:1295
__do_sys_sendfile64 fs/read_write.c:1362 [inline]
__se_sys_sendfile64 fs/read_write.c:1348 [inline]
__x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1348
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

write to 0xffff88813fa22784 of 4 bytes by task 21731 on cpu 0:
read_pages+0x284/0x540 mm/readahead.c:172
page_cache_ra_unbounded+0x2aa/0x2e0 mm/readahead.c:269
do_page_cache_ra mm/readahead.c:299 [inline]
page_cache_ra_order mm/readahead.c:544 [inline]
ondemand_readahead+0x50b/0x670 mm/readahead.c:666
page_cache_async_ra+0x94/0xa0 mm/readahead.c:715
filemap_readahead mm/filemap.c:2473 [inline]
filemap_get_pages+0x397/0xf90 mm/filemap.c:2514
filemap_read+0x214/0x680 mm/filemap.c:2594
generic_file_read_iter+0x78/0x330 mm/filemap.c:2784
ext4_file_read_iter+0x1d8/0x2a0
call_read_iter include/linux/fs.h:2079 [inline]
copy_splice_read+0x39f/0x5d0 fs/splice.c:365
do_splice_read fs/splice.c:984 [inline]
splice_direct_to_actor+0x288/0x660 fs/splice.c:1089
do_splice_direct_actor fs/splice.c:1207 [inline]
do_splice_direct+0xd7/0x150 fs/splice.c:1233
do_sendfile+0x3b9/0x960 fs/read_write.c:1295
__do_sys_sendfile64 fs/read_write.c:1362 [inline]
__se_sys_sendfile64 fs/read_write.c:1348 [inline]
__x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1348
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x00000009 -> 0x00000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 21731 Comm: syz-executor.4 Not tainted 6.8.0-rc4-syzkaller-00331-gc1ca10ceffbb #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.