==================================================================
BUG: KCSAN: data-race in copy_process / release_task

write to 0xffffffff89281410 of 4 bytes by task 11749 on cpu 0:
 __unhash_process kernel/exit.c:73 [inline]
 __exit_signal kernel/exit.c:147 [inline]
 release_task+0x6c8/0xb90 kernel/exit.c:198
 exit_notify kernel/exit.c:680 [inline]
 do_exit+0x1140/0x16e0 kernel/exit.c:826
 call_usermodehelper_exec_async+0x2da/0x2e0 kernel/umh.c:125
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

read to 0xffffffff89281410 of 4 bytes by task 2 on cpu 1:
 copy_process+0xab5/0x32b0 kernel/fork.c:1980
 _do_fork+0xf1/0x660 kernel/fork.c:2443
 kernel_thread+0x85/0xb0 kernel/fork.c:2531
 create_kthread kernel/kthread.c:314 [inline]
 kthreadd+0x317/0x3d0 kernel/kthread.c:632
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 2 Comm: kthreadd Not tainted 5.8.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 2 Comm: kthreadd Not tainted 5.8.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x10f/0x19d lib/dump_stack.c:118
 panic+0x1f8/0x63a kernel/panic.c:231
 kcsan_report+0x684/0x690 kernel/kcsan/report.c:626
 kcsan_setup_watchpoint+0x453/0x4d0 kernel/kcsan/core.c:519
 copy_process+0xab5/0x32b0 kernel/fork.c:1980
 _do_fork+0xf1/0x660 kernel/fork.c:2443
 kernel_thread+0x85/0xb0 kernel/fork.c:2531
 create_kthread kernel/kthread.c:314 [inline]
 kthreadd+0x317/0x3d0 kernel/kthread.c:632
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293
Kernel Offset: disabled
Rebooting in 86400 seconds..