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BUG: KCSAN: data-race in touch_atime / touch_atime

write to 0xffff888137b91280 of 8 bytes by task 26 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
 do_iter_readv_writev+0x2b0/0x330
 vfs_iter_read+0x172/0x390 fs/read_write.c:830
 lo_read_simple drivers/block/loop.c:286 [inline]
 do_req_filebacked drivers/block/loop.c:496 [inline]
 loop_handle_cmd drivers/block/loop.c:1909 [inline]
 loop_process_work+0x7a1/0x10e0 drivers/block/loop.c:1944
 loop_workfn+0x31/0x40 drivers/block/loop.c:1968
 process_one_work kernel/workqueue.c:2633 [inline]
 process_scheduled_works+0x5b8/0xa40 kernel/workqueue.c:2706
 worker_thread+0x525/0x730 kernel/workqueue.c:2787
 kthread+0x1d7/0x210 kernel/kthread.c:388
 ret_from_fork+0x48/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:243

read to 0xffff888137b91280 of 8 bytes by task 38 on cpu 1:
 inode_get_atime include/linux/fs.h:1537 [inline]
 inode_update_timestamps fs/inode.c:1873 [inline]
 generic_update_time fs/inode.c:1898 [inline]
 inode_update_time fs/inode.c:1918 [inline]
 touch_atime+0x19a/0x340 fs/inode.c:1990
 file_accessed include/linux/fs.h:2436 [inline]
 shmem_file_read_iter+0x4b3/0x550 mm/shmem.c:2873
 do_iter_readv_writev+0x2b0/0x330
 vfs_iter_read+0x172/0x390 fs/read_write.c:830
 lo_read_simple drivers/block/loop.c:286 [inline]
 do_req_filebacked drivers/block/loop.c:496 [inline]
 loop_handle_cmd drivers/block/loop.c:1909 [inline]
 loop_process_work+0x7a1/0x10e0 drivers/block/loop.c:1944
 loop_rootcg_workfn+0x22/0x30 drivers/block/loop.c:1975
 process_one_work kernel/workqueue.c:2633 [inline]
 process_scheduled_works+0x5b8/0xa40 kernel/workqueue.c:2706
 worker_thread+0x525/0x730 kernel/workqueue.c:2787
 kthread+0x1d7/0x210 kernel/kthread.c:388
 ret_from_fork+0x48/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:243

value changed: 0x0000000028e319c6 -> 0x00000000297bb046

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 38 Comm: kworker/u4:2 Not tainted 6.8.0-rc6-syzkaller-00120-g87adedeba51a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Workqueue: loop4 loop_rootcg_workfn
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