==================================================================
BUG: KCSAN: data-race in atime_needs_update / touch_atime

write to 0xffff88813a9b6fe0 of 8 bytes by task 14231 on cpu 0:
 inode_set_atime_to_ts include/linux/fs.h:1543 [inline]
 inode_update_timestamps fs/inode.c:1876 [inline]
 generic_update_time fs/inode.c:1898 [inline]
 inode_update_time fs/inode.c:1918 [inline]
 touch_atime+0x1ed/0x340 fs/inode.c:1990
 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

read to 0xffff88813a9b6fe0 of 8 bytes by task 14205 on cpu 1:
 atime_needs_update+0x264/0x3f0
 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: 0x000000000435ed2c -> 0x0000000005ffb0ad

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 14205 Comm: udevd Not tainted 6.8.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
==================================================================
I/O error, dev loop1, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0
I/O error, dev loop2, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0
I/O error, dev loop2, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
Buffer I/O error on dev loop2p3, logical block 0, async page read
udevd[14205]: inotify_add_watch(7, /dev/loop1p2, 10) failed: No such file or directory
udevd[14205]: inotify_add_watch(7, /dev/loop1p3, 10) failed: No such file or directory
udevd[14205]: inotify_add_watch(7, /dev/loop2p3, 10) failed: No such file or directory
blk_print_req_error: 27 callbacks suppressed
I/O error, dev loop0, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0
udevd[14205]: inotify_add_watch(7, /dev/loop2p3, 10) failed: No such file or directory
udevd[14205]: inotify_add_watch(7, /dev/loop2p3, 10) failed: No such file or directory