==================================================================
BUG: KCSAN: data-race in file_update_time / inode_update_timestamps

write to 0xffff88810ded67d0 of 8 bytes by task 8734 on cpu 1:
 inode_set_ctime_to_ts include/linux/fs.h:1624 [inline]
 inode_set_ctime_current fs/inode.c:2515 [inline]
 inode_update_timestamps+0xb5/0x280 fs/inode.c:1861
 generic_update_time fs/inode.c:1900 [inline]
 inode_update_time fs/inode.c:1920 [inline]
 __file_update_time fs/inode.c:2109 [inline]
 file_update_time+0x22f/0x2c0 fs/inode.c:2139
 pipe_write+0xa87/0xd30 fs/pipe.c:607
 call_write_iter include/linux/fs.h:2108 [inline]
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0x771/0x8e0 fs/read_write.c:590
 ksys_write+0xeb/0x1b0 fs/read_write.c:643
 __do_sys_write fs/read_write.c:655 [inline]
 __se_sys_write fs/read_write.c:652 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:652
 do_syscall_64+0xd3/0x1d0
 entry_SYSCALL_64_after_hwframe+0x72/0x7a

read to 0xffff88810ded67d0 of 8 bytes by task 8 on cpu 0:
 inode_get_ctime include/linux/fs.h:1618 [inline]
 inode_needs_update_time fs/inode.c:2092 [inline]
 file_update_time+0x107/0x2c0 fs/inode.c:2135
 pipe_write+0xa87/0xd30 fs/pipe.c:607
 __kernel_write_iter+0x265/0x490 fs/read_write.c:523
 __kernel_write fs/read_write.c:543 [inline]
 kernel_write+0x1f3/0x410 fs/read_write.c:564
 p9_fd_write net/9p/trans_fd.c:433 [inline]
 p9_write_work+0x32a/0x750 net/9p/trans_fd.c:484
 process_one_work kernel/workqueue.c:3254 [inline]
 process_scheduled_works+0x465/0x990 kernel/workqueue.c:3335
 worker_thread+0x526/0x730 kernel/workqueue.c:3416
 kthread+0x1d1/0x210 kernel/kthread.c:388
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243

value changed: 0x000000003094b298 -> 0x00000000368a939a

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 8 Comm: kworker/0:1 Tainted: G        W          6.9.0-rc2-syzkaller-00194-g8cb4a9a82b21 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Workqueue: events p9_write_work
==================================================================