[moderation] [fs?] [mm?] KCSAN: data-race in __xa_set_mark / filemap_write_and_wait_range

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 08733088b566 Merge tag 'rust-fixes-6.15-merge' of git://gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11acfbcf980000
kernel config: https://syzkaller.appspot.com/x/.config?x=bdb65086dcaf0454
dashboard link: https://syzkaller.appspot.com/bug?extid=e5b6f1ea1ecef0e5119b
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/5d1a68089fbc/disk-08733088.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/341882c01f34/vmlinux-08733088.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b16db8197b4e/bzImage-08733088.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e5b6f1...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in __xa_set_mark / filemap_write_and_wait_range

write to 0xffff888106963c54 of 4 bytes by task 15212 on cpu 1:
xa_mark_set lib/xarray.c:71 [inline]
xas_set_mark lib/xarray.c:899 [inline]
__xa_set_mark+0x192/0x1c0 lib/xarray.c:1943
__folio_mark_dirty+0x3b5/0x4e0 mm/page-writeback.c:2798
mark_buffer_dirty+0x134/0x230 fs/buffer.c:1196
__block_commit_write fs/buffer.c:2189 [inline]
block_write_end+0x123/0x210 fs/buffer.c:2265
ext4_write_end+0x148/0x770 fs/ext4/inode.c:1306
ext4_da_write_end+0x74/0x810 fs/ext4/inode.c:3076
generic_perform_write+0x31e/0x4b0 mm/filemap.c:4135
ext4_buffered_write_iter+0x1ed/0x3c0 fs/ext4/file.c:299
ext4_dio_write_iter fs/ext4/file.c:608 [inline]
ext4_file_write_iter+0xe49/0xf80 fs/ext4/file.c:716
iter_file_splice_write+0x5f2/0x980 fs/splice.c:738
do_splice_from fs/splice.c:935 [inline]
direct_splice_actor+0x160/0x2c0 fs/splice.c:1158
splice_direct_to_actor+0x305/0x680 fs/splice.c:1102
do_splice_direct_actor fs/splice.c:1201 [inline]
do_splice_direct+0xd9/0x150 fs/splice.c:1227
do_sendfile+0x40a/0x690 fs/read_write.c:1368
__do_sys_sendfile64 fs/read_write.c:1429 [inline]
__se_sys_sendfile64 fs/read_write.c:1415 [inline]
__x64_sys_sendfile64+0x113/0x160 fs/read_write.c:1415
x64_sys_call+0xfc3/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:41
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888106963c54 of 4 bytes by task 15224 on cpu 0:
xa_marked include/linux/xarray.h:424 [inline]
mapping_tagged include/linux/fs.h:540 [inline]
filemap_fdatawrite_wbc mm/filemap.c:385 [inline]
__filemap_fdatawrite_range mm/filemap.c:422 [inline]
filemap_write_and_wait_range+0x105/0x370 mm/filemap.c:694
ext4_dio_write_iter fs/ext4/file.c:621 [inline]
ext4_file_write_iter+0xe89/0xf80 fs/ext4/file.c:716
iter_file_splice_write+0x5f2/0x980 fs/splice.c:738
do_splice_from fs/splice.c:935 [inline]
direct_splice_actor+0x160/0x2c0 fs/splice.c:1158
splice_direct_to_actor+0x305/0x680 fs/splice.c:1102
do_splice_direct_actor fs/splice.c:1201 [inline]
do_splice_direct+0xd9/0x150 fs/splice.c:1227
do_sendfile+0x40a/0x690 fs/read_write.c:1368
__do_sys_sendfile64 fs/read_write.c:1429 [inline]
__se_sys_sendfile64 fs/read_write.c:1415 [inline]
__x64_sys_sendfile64+0x113/0x160 fs/read_write.c:1415
x64_sys_call+0xfc3/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:41
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000021 -> 0x0a000021

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 15224 Comm: syz.4.4006 Not tainted 6.14.0-syzkaller-11270-g08733088b566 #0 PREEMPT(voluntary)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
==================================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

[syzbot]

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