syzbot

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

write to 0xffff888118827540 of 4 bytes by task 5808 on cpu 0:
 inode_set_atime_to_ts include/linux/fs.h:1614 [inline]
 inode_update_timestamps fs/inode.c:2084 [inline]
 generic_update_time fs/inode.c:2106 [inline]
 inode_update_time fs/inode.c:2126 [inline]
 touch_atime+0x1f3/0x350 fs/inode.c:2198
 file_accessed include/linux/fs.h:2539 [inline]
 shmem_file_read_iter+0x4aa/0x550 mm/shmem.c:3249
 new_sync_read fs/read_write.c:484 [inline]
 vfs_read+0x5dc/0x700 fs/read_write.c:565
 ksys_read+0xe8/0x1b0 fs/read_write.c:708
 __do_sys_read fs/read_write.c:717 [inline]
 __se_sys_read fs/read_write.c:715 [inline]
 __x64_sys_read+0x42/0x50 fs/read_write.c:715
 x64_sys_call+0x2874/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:1
 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

read to 0xffff888118827540 of 4 bytes by task 5806 on cpu 1:
 atime_needs_update+0x261/0x3e0
 touch_atime+0x4a/0x350 fs/inode.c:2181
 file_accessed include/linux/fs.h:2539 [inline]
 shmem_file_read_iter+0x4aa/0x550 mm/shmem.c:3249
 new_sync_read fs/read_write.c:484 [inline]
 vfs_read+0x5dc/0x700 fs/read_write.c:565
 ksys_read+0xe8/0x1b0 fs/read_write.c:708
 __do_sys_read fs/read_write.c:717 [inline]
 __se_sys_read fs/read_write.c:715 [inline]
 __x64_sys_read+0x42/0x50 fs/read_write.c:715
 x64_sys_call+0x2874/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:1
 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: 0x167f0c57 -> 0x168c6891

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 5806 Comm: udevd Not tainted 6.12.0-syzkaller-01892-g8f7c8b88bda4 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
==================================================================