syzbot

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BUG: KCSAN: data-race in file_update_time / inode_update_timestamps

read to 0xffff8881162fcee4 of 4 bytes by task 4299 on cpu 0:
 inode_get_mtime_nsec include/linux/fs.h:1682 [inline]
 inode_get_mtime include/linux/fs.h:1688 [inline]
 inode_needs_update_time fs/inode.c:2332 [inline]
 file_update_time+0x8b/0x2b0 fs/inode.c:2379
 pipe_write+0xa7b/0xd20 fs/pipe.c:608
 new_sync_write fs/read_write.c:586 [inline]
 vfs_write+0x77b/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 0xffff8881162fcee4 of 4 bytes by task 4296 on cpu 1:
 inode_set_mtime_to_ts include/linux/fs.h:1696 [inline]
 inode_update_timestamps+0x139/0x250 fs/inode.c:2070
 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:608
 new_sync_write fs/read_write.c:586 [inline]
 vfs_write+0x77b/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: 0x0dff0320 -> 0x1b7db898

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 4296 Comm: syz.2.270 Not tainted 6.14.0-rc1-syzkaller-00020-g0de63bb7d919 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
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