[moderation] [exfat?] KCSAN: data-race in mark_buffer_dirty_inode / mark_buffer_dirty_inode (8)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: bee0e7762ad2 Merge tag 'for-linus-iommufd' of git://git.ke..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=140dc954e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=ac34c1f29a8029df
dashboard link: https://syzkaller.appspot.com/bug?extid=cf5f0d68e83fac44e8a3
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [hiro...@mail.parknet.co.jp linki...@kernel.org linux-...@vger.kernel.org linux-...@vger.kernel.org sj155...@samsung.com]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/233be5f65dd2/disk-bee0e776.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/94423738a289/vmlinux-bee0e776.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0b977463fa9a/bzImage-bee0e776.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+cf5f0d...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in mark_buffer_dirty_inode / mark_buffer_dirty_inode

write to 0xffff88813ebbf1f8 of 8 bytes by task 5151 on cpu 1:
mark_buffer_dirty_inode+0x190/0x1c0 fs/buffer.c:685
fat_mirror_bhs+0x247/0x340 fs/fat/fatent.c:398
fat_alloc_clusters+0x973/0xa60 fs/fat/fatent.c:543
fat_add_cluster fs/fat/inode.c:108 [inline]
__fat_get_block fs/fat/inode.c:155 [inline]
fat_get_block+0x25c/0x5e0 fs/fat/inode.c:190
__block_write_begin_int+0x3b7/0xf40 fs/buffer.c:2119
__block_write_begin fs/buffer.c:2168 [inline]
block_write_begin+0x7b/0x170 fs/buffer.c:2227
cont_write_begin+0x479/0x690 fs/buffer.c:2582
fat_write_begin+0x61/0xf0 fs/fat/inode.c:230
generic_perform_write+0x1c9/0x410 mm/filemap.c:3918
__generic_file_write_iter+0xa1/0x120 mm/filemap.c:4013
generic_file_write_iter+0x7d/0x1c0 mm/filemap.c:4039
do_iter_write+0x4ad/0x770 fs/read_write.c:860
vfs_iter_write+0x56/0x70 fs/read_write.c:901
iter_file_splice_write+0x462/0x7e0 fs/splice.c:736
do_splice_from fs/splice.c:933 [inline]
direct_splice_actor+0x8a/0xb0 fs/splice.c:1142
splice_direct_to_actor+0x31d/0x690 fs/splice.c:1088
do_splice_direct+0x10d/0x190 fs/splice.c:1194
do_sendfile+0x3c4/0x980 fs/read_write.c:1254
__do_sys_sendfile64 fs/read_write.c:1322 [inline]
__se_sys_sendfile64 fs/read_write.c:1308 [inline]
__x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1308
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff88813ebbf1f8 of 8 bytes by task 5146 on cpu 0:
mark_buffer_dirty_inode+0x96/0x1c0 fs/buffer.c:681
fat_mirror_bhs+0x247/0x340 fs/fat/fatent.c:398
fat_alloc_clusters+0x973/0xa60 fs/fat/fatent.c:543
fat_add_cluster fs/fat/inode.c:108 [inline]
__fat_get_block fs/fat/inode.c:155 [inline]
fat_get_block+0x25c/0x5e0 fs/fat/inode.c:190
__block_write_begin_int+0x3b7/0xf40 fs/buffer.c:2119
__block_write_begin fs/buffer.c:2168 [inline]
block_write_begin+0x7b/0x170 fs/buffer.c:2227
cont_write_begin+0x479/0x690 fs/buffer.c:2582
fat_write_begin+0x61/0xf0 fs/fat/inode.c:230
generic_perform_write+0x1c9/0x410 mm/filemap.c:3918
__generic_file_write_iter+0xa1/0x120 mm/filemap.c:4013
generic_file_write_iter+0x7d/0x1c0 mm/filemap.c:4039
call_write_iter include/linux/fs.h:2020 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x48a/0x790 fs/read_write.c:584
ksys_write+0xeb/0x1a0 fs/read_write.c:637
__do_sys_write fs/read_write.c:649 [inline]
__se_sys_write fs/read_write.c:646 [inline]
__x64_sys_write+0x42/0x50 fs/read_write.c:646
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x0000000000000000 -> 0xffff888108b65a50

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 5146 Comm: syz-executor.5 Not tainted 6.7.0-rc4-syzkaller-00009-gbee0e7762ad2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
==================================================================


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[syzbot]

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