syzbot

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BUG: KCSAN: data-race in atime_needs_update / shmem_setattr

write to 0xffff888107532d68 of 8 bytes by task 6831 on cpu 0:
 shmem_setattr+0x2ce/0x450 mm/shmem.c:1093
 notify_change+0x924/0xbf0 fs/attr.c:410
 do_truncate+0xf7/0x140 fs/open.c:65
 handle_truncate fs/namei.c:3132 [inline]
 do_open fs/namei.c:3480 [inline]
 path_openat+0x1873/0x1f30 fs/namei.c:3609
 do_filp_open+0x105/0x220 fs/namei.c:3636
 do_sys_openat2+0xb5/0x2b0 fs/open.c:1214
 do_sys_open fs/open.c:1230 [inline]
 __do_sys_creat fs/open.c:1306 [inline]
 __se_sys_creat fs/open.c:1300 [inline]
 __x64_sys_creat+0x62/0x80 fs/open.c:1300
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888107532d68 of 8 bytes by task 6827 on cpu 1:
 timespec64_compare include/linux/time64.h:60 [inline]
 relatime_need_update fs/inode.c:1815 [inline]
 atime_needs_update+0x425/0x4b0 fs/inode.c:1908
 touch_atime+0x63/0x2e0 fs/inode.c:1923
 file_accessed include/linux/fs.h:2421 [inline]
 generic_file_splice_read+0x2a9/0x330 fs/splice.c:314
 do_splice_to fs/splice.c:796 [inline]
 splice_direct_to_actor+0x2aa/0x650 fs/splice.c:870
 do_splice_direct+0x106/0x190 fs/splice.c:979
 do_sendfile+0x675/0xc40 fs/read_write.c:1245
 __do_sys_sendfile64 fs/read_write.c:1304 [inline]
 __se_sys_sendfile64 fs/read_write.c:1296 [inline]
 __x64_sys_sendfile64+0xb9/0x140 fs/read_write.c:1296
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x000000002bc5bedb -> 0x000000002e2818db

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 6827 Comm: syz-executor.1 Not tainted 5.17.0-rc8-syzkaller-00072-g97e9c8eb4bb1-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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