KCSAN: data-race in file_update_time / inode_set_ctime_to

Kernel	Title	Rank 🛈	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in file_update_time / inode_set_ctime_to_ts (2) fs	6				2	259d	264d	0/29	auto-obsoleted due to no activity on 2026/01/20 08:54

BUG: KCSAN: data-race in file_update_time / inode_set_ctime_to_ts

read to 0xffff8881061c27b0 of 4 bytes by task 7641 on cpu 0:
 inode_get_ctime_nsec include/linux/fs.h:1678 [inline]
 inode_get_ctime include/linux/fs.h:1684 [inline]
 inode_needs_update_time fs/inode.c:2336 [inline]
 file_update_time+0xeb/0x2b0 fs/inode.c:2379
 pipe_write+0xa7b/0xd20 fs/pipe.c:607
 new_sync_write fs/read_write.c:586 [inline]
 vfs_write+0x77f/0x920 fs/read_write.c:679
 ksys_write+0xe8/0x1b0 fs/read_write.c:731
 __do_sys_write fs/read_write.c:742 [inline]
 __se_sys_write fs/read_write.c:739 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:739
 x64_sys_call+0x287e/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:2
 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

write to 0xffff8881061c27b0 of 4 bytes by task 7638 on cpu 1:
 inode_set_ctime_to_ts+0x85/0x180 fs/inode.c:2716
 inode_set_ctime_current+0x1b7/0x7a0 fs/inode.c:2779
 inode_update_timestamps+0x85/0x250 fs/inode.c:2066
 generic_update_time fs/inode.c:2105 [inline]
 inode_update_time fs/inode.c:2125 [inline]
 __file_update_time fs/inode.c:2353 [inline]
 file_update_time+0x219/0x2b0 fs/inode.c:2383
 pipe_write+0xa7b/0xd20 fs/pipe.c:607
 new_sync_write fs/read_write.c:586 [inline]
 vfs_write+0x77f/0x920 fs/read_write.c:679
 ksys_write+0xe8/0x1b0 fs/read_write.c:731
 __do_sys_write fs/read_write.c:742 [inline]
 __se_sys_write fs/read_write.c:739 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:739
 x64_sys_call+0x287e/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:2
 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: 0x260a5345 -> 0x2dc9f7c8

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 7638 Comm: syz.1.1661 Not tainted 6.13.0-rc2-syzkaller-00036-g231825b2e1ff #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
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