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BUG: KCSAN: data-race in touch_atime / touch_atime

write to 0xffff888140deebe0 of 8 bytes by task 23746 on cpu 1:
 inode_update_timestamps fs/inode.c:1907 [inline]
 generic_update_time fs/inode.c:1929 [inline]
 inode_update_time fs/inode.c:1949 [inline]
 touch_atime+0x31f/0x4a0 fs/inode.c:2020
 file_accessed include/linux/fs.h:2320 [inline]
 shmem_file_read_iter+0x570/0x5b0 mm/shmem.c:2845
 call_read_iter include/linux/fs.h:1979 [inline]
 new_sync_read fs/read_write.c:389 [inline]
 vfs_read+0x3da/0x5c0 fs/read_write.c:470
 ksys_read+0xeb/0x1a0 fs/read_write.c:613
 __do_sys_read fs/read_write.c:623 [inline]
 __se_sys_read fs/read_write.c:621 [inline]
 __x64_sys_read+0x42/0x50 fs/read_write.c:621
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff888140deebe0 of 8 bytes by task 23863 on cpu 0:
 timespec64_equal include/linux/time64.h:49 [inline]
 inode_update_timestamps fs/inode.c:1906 [inline]
 generic_update_time fs/inode.c:1929 [inline]
 inode_update_time fs/inode.c:1949 [inline]
 touch_atime+0x2d8/0x4a0 fs/inode.c:2020
 file_accessed include/linux/fs.h:2320 [inline]
 shmem_file_read_iter+0x570/0x5b0 mm/shmem.c:2845
 call_read_iter include/linux/fs.h:1979 [inline]
 new_sync_read fs/read_write.c:389 [inline]
 vfs_read+0x3da/0x5c0 fs/read_write.c:470
 ksys_read+0xeb/0x1a0 fs/read_write.c:613
 __do_sys_read fs/read_write.c:623 [inline]
 __se_sys_read fs/read_write.c:621 [inline]
 __x64_sys_read+0x42/0x50 fs/read_write.c:621
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x000000000db5b719 -> 0x000000000e4e4d9a

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 23863 Comm: udevd Tainted: G        W          6.6.0-rc1-syzkaller-00196-g57d88e8a5974 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/04/2023
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I/O error, dev loop2, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 2
I/O error, dev loop2, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 2
Buffer I/O error on dev loop2, logical block 0, async page read
I/O error, dev loop2, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 2