==================================================================
BUG: KCSAN: data-race in do_msgrcv / do_signal_stop

write to 0xffff8880b9c99050 of 8 bytes by task 8444 on cpu 0:
 do_msgrcv+0x912/0xd20 ipc/msg.c:1184
 ksys_msgrcv ipc/msg.c:1257 [inline]
 __do_sys_msgrcv ipc/msg.c:1263 [inline]
 __se_sys_msgrcv ipc/msg.c:1260 [inline]
 __x64_sys_msgrcv+0x73/0x90 ipc/msg.c:1260
 do_syscall_64+0xc7/0x390 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880b9c99050 of 8 bytes by task 8442 on cpu 1:
 do_signal_stop+0x3cc/0x4e0 kernel/signal.c:2348
 get_signal+0x601/0x1290 kernel/signal.c:2694
 do_signal+0x2b/0x670 arch/x86/kernel/signal.c:813
 exit_to_usermode_loop+0x24a/0x2c0 arch/x86/entry/common.c:160
 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:278 [inline]
 do_syscall_64+0x36e/0x390 arch/x86/entry/common.c:304
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 8442 Comm: syz-executor.4 Not tainted 5.6.0-rc1-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: 8442 Comm: syz-executor.4 Not tainted 5.6.0-rc1-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/0x187 lib/dump_stack.c:118
 panic+0x210/0x640 kernel/panic.c:221
 kcsan_report.cold+0xc/0xf kernel/kcsan/report.c:599
 kcsan_setup_watchpoint+0x3fb/0x440 kernel/kcsan/core.c:507
 do_signal_stop+0x3cc/0x4e0 kernel/signal.c:2348
 get_signal+0x601/0x1290 kernel/signal.c:2694
 do_signal+0x2b/0x670 arch/x86/kernel/signal.c:813
 exit_to_usermode_loop+0x24a/0x2c0 arch/x86/entry/common.c:160
 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:278 [inline]
 do_syscall_64+0x36e/0x390 arch/x86/entry/common.c:304
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45c889
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:00007ffec2298728 EFLAGS: 00000246 ORIG_RAX: 00000000000000db
RAX: fffffffffffffdfc RBX: 00000000000003e8 RCX: 000000000045c889
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000076c04c
RBP: 000000000000002d R08: 01ffffffffffffff R09: 01ffffffffffffff
R10: 00007ffec2298800 R11: 0000000000000246 R12: 000000000076c040
R13: 00000000000179d2 R14: 00000000000179ff R15: 000000000076c04c
Shutting down cpus with NMI
Kernel Offset: disabled
Rebooting in 86400 seconds..