syzbot

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BUG: KCSAN: data-race in atime_needs_update / touch_atime

write to 0xffff888101fd1968 of 4 bytes by task 19580 on cpu 1:
 inode_set_atime_to_ts include/linux/fs.h:1626 [inline]
 inode_update_atime fs/inode.c:2160 [inline]
 inode_update_time fs/inode.c:2224 [inline]
 generic_update_time fs/inode.c:2257 [inline]
 touch_atime+0x1cb/0x300 fs/inode.c:2335
 file_accessed include/linux/fs.h:2277 [inline]
 shmem_file_read_iter+0x3ed/0x4b0 mm/shmem.c:3394
 copy_splice_read+0x47a/0x6b0 fs/splice.c:362
 do_splice_read fs/splice.c:979 [inline]
 splice_direct_to_actor+0x27c/0x680 fs/splice.c:1084
 do_splice_direct_actor fs/splice.c:1202 [inline]
 do_splice_direct+0x119/0x1a0 fs/splice.c:1228
 do_sendfile+0x37d/0x640 fs/read_write.c:1371
 __do_sys_sendfile64 fs/read_write.c:1432 [inline]
 __se_sys_sendfile64 fs/read_write.c:1418 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1418
 x64_sys_call+0x2dc4/0x3020 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888101fd1968 of 4 bytes by task 19579 on cpu 0:
 atime_needs_update+0x25f/0x3e0 fs/inode.c:-1
 touch_atime+0x4a/0x300 fs/inode.c:2315
 file_accessed include/linux/fs.h:2277 [inline]
 shmem_file_read_iter+0x3ed/0x4b0 mm/shmem.c:3394
 copy_splice_read+0x47a/0x6b0 fs/splice.c:362
 do_splice_read fs/splice.c:979 [inline]
 splice_direct_to_actor+0x27c/0x680 fs/splice.c:1084
 do_splice_direct_actor fs/splice.c:1202 [inline]
 do_splice_direct+0x119/0x1a0 fs/splice.c:1228
 do_sendfile+0x37d/0x640 fs/read_write.c:1371
 __do_sys_sendfile64 fs/read_write.c:1432 [inline]
 __se_sys_sendfile64 fs/read_write.c:1418 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1418
 x64_sys_call+0x2dc4/0x3020 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x24f3c002 -> 0x258c5682

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 19579 Comm: syz.9.4506 Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
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