syzbot

==================================================================
BUG: KCSAN: data-race in do_group_exit / do_group_exit

write to 0xffff88811f265634 of 4 bytes by task 3540 on cpu 1:
 do_group_exit+0x1a6/0x1c0 kernel/exit.c:915
 __do_sys_exit_group kernel/exit.c:932 [inline]
 __se_sys_exit_group kernel/exit.c:930 [inline]
 __x64_sys_exit_group+0x2e/0x30 kernel/exit.c:930
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88811f265634 of 4 bytes by task 3533 on cpu 0:
 do_group_exit+0x7b/0x1c0 kernel/exit.c:904
 __do_sys_exit_group kernel/exit.c:932 [inline]
 __se_sys_exit_group kernel/exit.c:930 [inline]
 __x64_sys_exit_group+0x2e/0x30 kernel/exit.c:930
 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: 0 PID: 3533 Comm: syz-executor.2 Not tainted 5.4.0-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: 0 PID: 3533 Comm: syz-executor.2 Not tainted 5.4.0-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+0x11d/0x181 lib/dump_stack.c:118
 panic+0x210/0x640 kernel/panic.c:221
 kcsan_report.cold+0xc/0xd kernel/kcsan/report.c:315
 kcsan_setup_watchpoint+0x3fe/0x460 kernel/kcsan/core.c:423
 check_access kernel/kcsan/core.c:466 [inline]
 __tsan_read4 kernel/kcsan/core.c:595 [inline]
 __tsan_read4+0xc6/0x100 kernel/kcsan/core.c:595
 do_group_exit+0x7b/0x1c0 kernel/exit.c:904
 __do_sys_exit_group kernel/exit.c:932 [inline]
 __se_sys_exit_group kernel/exit.c:930 [inline]
 __x64_sys_exit_group+0x2e/0x30 kernel/exit.c:930
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45a909
Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fc265fbd6c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000007 RCX: 000000000045a909
RDX: 0000000000000003 RSI: 00007fc265fbd700 RDI: 0000000000000007
RBP: 000000000075bf20 R08: 00007fc265fbe700 R09: 0000000000000000
R10: 00007fc265fbe700 R11: 0000000000000246 R12: 000000000075bf60
R13: 00000000004ca8c9 R14: 00000000004e3a90 R15: 00000000ffffffff
Kernel Offset: disabled
Rebooting in 86400 seconds..