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

write to 0xffff88811b6ef540 of 4 bytes by task 37 on cpu 1:
 inode_set_atime_to_ts include/linux/fs.h:1624 [inline]
 inode_update_timestamps fs/inode.c:2126 [inline]
 generic_update_time fs/inode.c:2148 [inline]
 inode_update_time fs/inode.c:2168 [inline]
 touch_atime+0x1e8/0x340 fs/inode.c:2240
 file_accessed include/linux/fs.h:2254 [inline]
 shmem_file_read_iter+0x477/0x540 mm/shmem.c:3470
 lo_rw_aio+0x673/0x720 drivers/block/loop.c:-1
 do_req_filebacked drivers/block/loop.c:-1 [inline]
 loop_handle_cmd drivers/block/loop.c:1926 [inline]
 loop_process_work+0x56d/0xaa0 drivers/block/loop.c:1961
 loop_rootcg_workfn+0x22/0x30 drivers/block/loop.c:1992
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3340
 worker_thread+0x582/0x770 kernel/workqueue.c:3421
 kthread+0x489/0x510 kernel/kthread.c:463
 ret_from_fork+0x149/0x290 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

read to 0xffff88811b6ef540 of 4 bytes by task 2812 on cpu 0:
 inode_get_atime_nsec include/linux/fs.h:1609 [inline]
 inode_get_atime include/linux/fs.h:1615 [inline]
 inode_update_timestamps fs/inode.c:2123 [inline]
 generic_update_time fs/inode.c:2148 [inline]
 inode_update_time fs/inode.c:2168 [inline]
 touch_atime+0x194/0x340 fs/inode.c:2240
 file_accessed include/linux/fs.h:2254 [inline]
 shmem_file_read_iter+0x477/0x540 mm/shmem.c:3470
 lo_rw_aio+0x673/0x720 drivers/block/loop.c:-1
 do_req_filebacked drivers/block/loop.c:-1 [inline]
 loop_handle_cmd drivers/block/loop.c:1926 [inline]
 loop_process_work+0x56d/0xaa0 drivers/block/loop.c:1961
 loop_workfn+0x31/0x40 drivers/block/loop.c:1985
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3340
 worker_thread+0x582/0x770 kernel/workqueue.c:3421
 kthread+0x489/0x510 kernel/kthread.c:463
 ret_from_fork+0x149/0x290 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

value changed: 0x2837686f -> 0x2968956f

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 2812 Comm: kworker/u8:12 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: loop5 loop_workfn

==================================================================