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BUG: KCSAN: data-race in touch_atime / touch_atime

write to 0xffff88811cc51668 of 4 bytes by task 16344 on cpu 0:
 inode_set_atime_to_ts include/linux/fs.h:1626 [inline]
 inode_update_atime fs/inode.c:2098 [inline]
 inode_update_time fs/inode.c:2162 [inline]
 generic_update_time fs/inode.c:2195 [inline]
 touch_atime+0x1d7/0x330 fs/inode.c:2273
 file_accessed include/linux/fs.h:2264 [inline]
 shmem_file_read_iter+0x3f4/0x4b0 mm/shmem.c:3458
 new_sync_read fs/read_write.c:493 [inline]
 vfs_read+0x6c0/0x7f0 fs/read_write.c:574
 ksys_read+0xdc/0x1a0 fs/read_write.c:717
 __do_sys_read fs/read_write.c:726 [inline]
 __se_sys_read fs/read_write.c:724 [inline]
 __x64_sys_read+0x40/0x50 fs/read_write.c:724
 x64_sys_call+0x2886/0x3020 arch/x86/include/generated/asm/syscalls_64.h:1
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88811cc51668 of 4 bytes by task 16349 on cpu 1:
 inode_get_atime_nsec include/linux/fs.h:1611 [inline]
 inode_get_atime include/linux/fs.h:1617 [inline]
 inode_update_atime fs/inode.c:2092 [inline]
 inode_update_time fs/inode.c:2162 [inline]
 generic_update_time fs/inode.c:2195 [inline]
 touch_atime+0x16c/0x330 fs/inode.c:2273
 file_accessed include/linux/fs.h:2264 [inline]
 shmem_file_read_iter+0x3f4/0x4b0 mm/shmem.c:3458
 new_sync_read fs/read_write.c:493 [inline]
 vfs_read+0x6c0/0x7f0 fs/read_write.c:574
 ksys_read+0xdc/0x1a0 fs/read_write.c:717
 __do_sys_read fs/read_write.c:726 [inline]
 __se_sys_read fs/read_write.c:724 [inline]
 __x64_sys_read+0x40/0x50 fs/read_write.c:724
 x64_sys_call+0x2886/0x3020 arch/x86/include/generated/asm/syscalls_64.h:1
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x23634d8a -> 0x237f6f0d

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 16349 Comm: udevd Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
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