syzbot

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BUG: KCSAN: data-race in exit_signals / task_dump_owner

write to 0xffff8881230150e4 of 4 bytes by task 28602 on cpu 0:
 exit_signals+0x13b/0x490 kernel/signal.c:2822
 do_exit+0x188/0x18c0 kernel/exit.c:754
 do_group_exit+0xb4/0x1c0 kernel/exit.c:895
 __do_sys_exit_group kernel/exit.c:906 [inline]
 __se_sys_exit_group kernel/exit.c:904 [inline]
 __x64_sys_exit_group+0x2e/0x30 kernel/exit.c:904
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8881230150e4 of 4 bytes by task 28605 on cpu 1:
 task_dump_owner+0x43/0x260 fs/proc/base.c:1698
 pid_update_inode+0x3c/0x70 fs/proc/base.c:1818
 pid_revalidate+0x91/0x120 fs/proc/base.c:1841
 d_revalidate fs/namei.c:758 [inline]
 d_revalidate fs/namei.c:755 [inline]
 lookup_fast+0x6ac/0x6c0 fs/namei.c:1613
 walk_component+0x6d/0xd90 fs/namei.c:1798
 link_path_walk.part.0+0x354/0xa90 fs/namei.c:2125
 link_path_walk fs/namei.c:2059 [inline]
 path_openat+0x14f/0x3580 fs/namei.c:3536
 do_filp_open+0x11e/0x1b0 fs/namei.c:3567
 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/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 28605 Comm: syz-executor.4 Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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