syzbot

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BUG: KCSAN: data-race in inode_permission / task_dump_owner

read to 0xffff8881257c82ec of 4 bytes by task 9696 on cpu 0:
 inode_permission+0x1bd/0x3c0 fs/namei.c:446
 may_open.isra.0+0x144/0x250 fs/namei.c:2963
 do_last fs/namei.c:3404 [inline]
 path_openat+0xf05/0x36e0 fs/namei.c:3525
 do_filp_open+0x11e/0x1b0 fs/namei.c:3555
 do_sys_open+0x3b3/0x4f0 fs/open.c:1097
 __do_sys_open fs/open.c:1115 [inline]
 __se_sys_open fs/open.c:1110 [inline]
 __x64_sys_open+0x55/0x70 fs/open.c:1110
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff8881257c82ec of 4 bytes by task 9698 on cpu 1:
 task_dump_owner+0xd8/0x260 fs/proc/base.c:1742
 tid_fd_update_inode+0x36/0xe0 fs/proc/fd.c:104
 tid_fd_revalidate+0x113/0x170 fs/proc/fd.c:133
 d_revalidate fs/namei.c:758 [inline]
 d_revalidate fs/namei.c:755 [inline]
 lookup_fast+0x618/0x700 fs/namei.c:1612
 do_last fs/namei.c:3274 [inline]
 path_openat+0x2ac/0x36e0 fs/namei.c:3525
 do_filp_open+0x11e/0x1b0 fs/namei.c:3555
 do_sys_open+0x3b3/0x4f0 fs/open.c:1097
 __do_sys_open fs/open.c:1115 [inline]
 __se_sys_open fs/open.c:1110 [inline]
 __x64_sys_open+0x55/0x70 fs/open.c:1110
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 9698 Comm: syz-executor.0 Not tainted 5.4.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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