BUG: KCSAN: data-race in atime_needs_update / inode_update_timestamps

write to 0xffff888126edc0f0 of 8 bytes by task 7657 on cpu 1:
 inode_set_mtime_to_ts include/linux/fs.h:1573 [inline]
 inode_update_timestamps+0x16f/0x280 fs/inode.c:1863
 generic_update_time fs/inode.c:1898 [inline]
 inode_update_time fs/inode.c:1918 [inline]
 __file_update_time fs/inode.c:2106 [inline]
 file_update_time+0x229/0x2b0 fs/inode.c:2136
 shmem_file_write_iter+0x9f/0xe0 mm/shmem.c:2890
 call_write_iter include/linux/fs.h:2087 [inline]
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0x760/0x8d0 fs/read_write.c:590
 ksys_write+0xeb/0x1a0 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_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff888126edc0f0 of 8 bytes by task 6039 on cpu 0:
 inode_get_mtime include/linux/fs.h:1567 [inline]
 relatime_need_update fs/inode.c:1812 [inline]
 atime_needs_update+0x2ce/0x3f0 fs/inode.c:1958
 touch_atime+0x4a/0x340 fs/inode.c:1973
 file_accessed include/linux/fs.h:2436 [inline]
 shmem_file_read_iter+0x4b3/0x550 mm/shmem.c:2873
 call_read_iter include/linux/fs.h:2081 [inline]
 new_sync_read fs/read_write.c:395 [inline]
 vfs_read+0x5ab/0x6a0 fs/read_write.c:476
 ksys_read+0xeb/0x1a0 fs/read_write.c:619
 __do_sys_read fs/read_write.c:629 [inline]
 __se_sys_read fs/read_write.c:627 [inline]
 __x64_sys_read+0x42/0x50 fs/read_write.c:627
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x000000003473b898 -> 0x0000000001c9c018

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 6039 Comm: udevd Not tainted 6.8.0-rc7-syzkaller-00142-g3aaa8ce7a335 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
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