syzbot

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BUG: KCSAN: data-race in do_signal_stop / task_dump_owner

read-write to 0xffff8881080c3024 of 4 bytes by task 28997 on cpu 1:
 freezer_do_not_count include/linux/freezer.h:109 [inline]
 freezable_schedule include/linux/freezer.h:171 [inline]
 do_signal_stop+0x533/0x6b0 kernel/signal.c:2396
 get_signal+0xa83/0x1510 kernel/signal.c:2718
 arch_do_signal+0x25/0x260 arch/x86/kernel/signal.c:811
 exit_to_user_mode_loop kernel/entry/common.c:161 [inline]
 exit_to_user_mode_prepare+0xde/0x170 kernel/entry/common.c:191
 irqentry_exit_to_user_mode+0x5/0x20 kernel/entry/common.c:279
 irqentry_exit+0xe/0x40 kernel/entry/common.c:367
 sysvec_apic_timer_interrupt+0x80/0x90 arch/x86/kernel/apic/apic.c:1091
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:631

read to 0xffff8881080c3024 of 4 bytes by task 29000 on cpu 0:
 task_dump_owner+0x2b/0x1b0 fs/proc/base.c:1823
 pid_update_inode fs/proc/base.c:1965 [inline]
 pid_revalidate+0x69/0x110 fs/proc/base.c:1988
 lookup_fast+0x208/0x370 fs/namei.c:768
 walk_component+0x5c/0x350 fs/namei.c:1857
 link_path_walk+0x451/0x710 fs/namei.c:2180
 path_openat+0x19f/0x20a0 fs/namei.c:3365
 do_filp_open+0xbd/0x1d0 fs/namei.c:3396
 do_sys_openat2+0xa3/0x240 fs/open.c:1168
 do_sys_open fs/open.c:1184 [inline]
 __do_sys_open fs/open.c:1192 [inline]
 __se_sys_open fs/open.c:1188 [inline]
 __x64_sys_open+0xe2/0x110 fs/open.c:1188
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 29000 Comm: syz-executor.3 Not tainted 5.10.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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