==================================================================
BUG: KCSAN: data-race in syscall_trace_enter / zap_other_threads

write to 0xffff8880620b1760 of 8 bytes by task 8519 on cpu 0:
 sigaddset include/linux/signal.h:66 [inline]
 zap_other_threads+0x116/0x1e0 kernel/signal.c:1361
 do_group_exit+0x146/0x180 kernel/exit.c:898
 __do_sys_exit_group+0xb/0x10 kernel/exit.c:914
 __se_sys_exit_group+0x5/0x10 kernel/exit.c:912
 __x64_sys_exit_group+0x16/0x20 kernel/exit.c:912
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880620b1760 of 8 bytes by task 8522 on cpu 1:
 sigismember include/linux/signal.h:84 [inline]
 __fatal_signal_pending include/linux/sched/signal.h:363 [inline]
 fatal_signal_pending include/linux/sched/signal.h:368 [inline]
 ptrace_report_syscall include/linux/tracehook.h:79 [inline]
 tracehook_report_syscall_entry include/linux/tracehook.h:104 [inline]
 syscall_trace_enter+0xfb/0x3e0 arch/x86/entry/common.c:159
 do_syscall_64+0x28/0xb0 arch/x86/entry/common.c:380
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 8522 Comm: syz-executor.0 Not tainted 5.8.0-rc5-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: 8522 Comm: syz-executor.0 Not tainted 5.8.0-rc5-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+0x207/0x64a kernel/panic.c:231
 kcsan_report+0x684/0x690 kernel/kcsan/report.c:626
 kcsan_setup_watchpoint+0x453/0x4d0 kernel/kcsan/core.c:519
 sigismember include/linux/signal.h:84 [inline]
 __fatal_signal_pending include/linux/sched/signal.h:363 [inline]
 fatal_signal_pending include/linux/sched/signal.h:368 [inline]
 ptrace_report_syscall include/linux/tracehook.h:79 [inline]
 tracehook_report_syscall_entry include/linux/tracehook.h:104 [inline]
 syscall_trace_enter+0xfb/0x3e0 arch/x86/entry/common.c:159
 do_syscall_64+0x28/0xb0 arch/x86/entry/common.c:380
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45cba9
Code: Bad RIP value.
RSP: 002b:00007f72d18e0c78 EFLAGS: 00000246 ORIG_RAX: 000000000000003d
RAX: ffffffffffffffda RBX: 000000000050d9e0 RCX: 000000000045cba9
RDX: 0000000080000002 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000ce3 R14: 00000000004cf282 R15: 00007f72d18e16d4
Kernel Offset: disabled
Rebooting in 86400 seconds..