[moderation] [ext4?] KCSAN: data-race in __mark_inode_dirty / writeback_sb_inodes (15)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 4a4be1ad3a6e Revert "vfs: Delete the associated dentry whe..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1184bc06980000
kernel config: https://syzkaller.appspot.com/x/.config?x=b639694183430f97
dashboard link: https://syzkaller.appspot.com/bug?extid=4521a771aa35695c3147
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [adilger...@dilger.ca linux...@vger.kernel.org linux-...@vger.kernel.org ty...@mit.edu]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/2ce114511169/disk-4a4be1ad.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/de93663819ec/vmlinux-4a4be1ad.xz
kernel image: https://storage.googleapis.com/syzbot-assets/58702aa7dc80/bzImage-4a4be1ad.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4521a7...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in __mark_inode_dirty / writeback_sb_inodes

write to 0xffff888100493880 of 8 bytes by task 9586 on cpu 1:
writeback_sb_inodes+0x31b/0xb20 fs/fs-writeback.c:1936
__writeback_inodes_wb+0x9a/0x1a0 fs/fs-writeback.c:2018
wb_writeback+0x270/0x720 fs/fs-writeback.c:2129
wb_check_start_all fs/fs-writeback.c:2255 [inline]
wb_do_writeback fs/fs-writeback.c:2281 [inline]
wb_workfn+0x4ea/0x940 fs/fs-writeback.c:2314
process_one_work kernel/workqueue.c:3231 [inline]
process_scheduled_works+0x483/0x9a0 kernel/workqueue.c:3312
worker_thread+0x526/0x730 kernel/workqueue.c:3393
kthread+0x1d1/0x210 kernel/kthread.c:389
ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

read to 0xffff888100493880 of 8 bytes by task 11714 on cpu 0:
__mark_inode_dirty+0x19f/0x7e0 fs/fs-writeback.c:2508
generic_update_time fs/inode.c:1907 [inline]
inode_update_time fs/inode.c:1920 [inline]
__file_update_time fs/inode.c:2109 [inline]
file_modified_flags+0x30f/0x340 fs/inode.c:2180
file_modified+0x17/0x20 fs/inode.c:2196
ext4_dio_write_checks fs/ext4/file.c:485 [inline]
ext4_dio_write_iter fs/ext4/file.c:551 [inline]
ext4_file_write_iter+0x8b8/0xe30 fs/ext4/file.c:696
iter_file_splice_write+0x5e6/0x970 fs/splice.c:743
do_splice_from fs/splice.c:941 [inline]
direct_splice_actor+0x16c/0x2c0 fs/splice.c:1164
splice_direct_to_actor+0x305/0x670 fs/splice.c:1108
do_splice_direct_actor fs/splice.c:1207 [inline]
do_splice_direct+0xd7/0x150 fs/splice.c:1233
do_sendfile+0x3ab/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
x64_sys_call+0x2c9f/0x2d70 arch/x86/include/generated/asm/syscalls_64.h:41
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000020007 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 11714 Comm: syz-executor.3 Tainted: G W 6.10.0-rc1-syzkaller-00027-g4a4be1ad3a6e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
==================================================================


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