loop3: p1 < > p4
loop3: p4 size 8388608 extends beyond EOD, truncated
==================================================================
BUG: KCSAN: data-race in atime_needs_update / touch_atime

write to 0xffff8881048020e8 of 4 bytes by task 4646 on cpu 1:
 inode_set_atime_to_ts include/linux/fs.h:1685 [inline]
 inode_update_timestamps fs/inode.c:2034 [inline]
 generic_update_time fs/inode.c:2056 [inline]
 inode_update_time fs/inode.c:2076 [inline]
 touch_atime+0x1e8/0x340 fs/inode.c:2148
 file_accessed include/linux/fs.h:2661 [inline]
 shmem_file_read_iter+0x477/0x540 mm/shmem.c:3447
 new_sync_read fs/read_write.c:491 [inline]
 vfs_read+0x5ca/0x6f0 fs/read_write.c:572
 ksys_read+0xda/0x1a0 fs/read_write.c:715
 __do_sys_read fs/read_write.c:724 [inline]
 __se_sys_read fs/read_write.c:722 [inline]
 __x64_sys_read+0x40/0x50 fs/read_write.c:722
 x64_sys_call+0x27bc/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:1
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881048020e8 of 4 bytes by task 4645 on cpu 0:
 atime_needs_update+0x25f/0x3e0 fs/inode.c:-1
 touch_atime+0x4a/0x340 fs/inode.c:2131
 file_accessed include/linux/fs.h:2661 [inline]
 shmem_file_read_iter+0x477/0x540 mm/shmem.c:3447
 new_sync_read fs/read_write.c:491 [inline]
 vfs_read+0x5ca/0x6f0 fs/read_write.c:572
 ksys_read+0xda/0x1a0 fs/read_write.c:715
 __do_sys_read fs/read_write.c:724 [inline]
 __se_sys_read fs/read_write.c:722 [inline]
 __x64_sys_read+0x40/0x50 fs/read_write.c:722
 x64_sys_call+0x27bc/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:1
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x335bc027 -> 0x3373e826

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 4645 Comm: udevd Not tainted 6.16.0-syzkaller-08685-g260f6f4fda93 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
==================================================================
udevd[4645]: inotify_add_watch(7, /dev/loop3p1, 10) failed: No such file or directory
udevd[4645]: inotify_add_watch(7, /dev/loop3p1, 10) failed: No such file or directory
udevd[4645]: inotify_add_watch(7, /dev/loop3p1, 10) failed: No such file or directory