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

write to 0xffff8881312d80f0 of 4 bytes by task 11630 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
 copy_splice_read+0x442/0x660 fs/splice.c:363
 do_splice_read fs/splice.c:981 [inline]
 splice_direct_to_actor+0x290/0x680 fs/splice.c:1086
 do_splice_direct_actor fs/splice.c:1204 [inline]
 do_splice_direct+0xda/0x150 fs/splice.c:1230
 do_sendfile+0x380/0x650 fs/read_write.c:1370
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64 fs/read_write.c:1417 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1417
 x64_sys_call+0x2db1/0x3000 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xca/0x2b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881312d80f0 of 4 bytes by task 11643 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
 copy_splice_read+0x442/0x660 fs/splice.c:363
 do_splice_read fs/splice.c:981 [inline]
 splice_direct_to_actor+0x290/0x680 fs/splice.c:1086
 do_splice_direct_actor fs/splice.c:1204 [inline]
 do_splice_direct+0xda/0x150 fs/splice.c:1230
 do_sendfile+0x380/0x650 fs/read_write.c:1370
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64 fs/read_write.c:1417 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1417
 x64_sys_call+0x2db1/0x3000 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xca/0x2b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x18da7e45 -> 0x19731975

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 11643 Comm: syz.1.1510 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
==================================================================