==================================================================
BUG: KCSAN: data-race in ptrace_check_attach / ptrace_stop

write to 0xffff8881257f2090 of 8 bytes by task 15377 on cpu 0:
 ptrace_stop+0x5e/0x4f0 kernel/signal.c:2145
 ptrace_signal kernel/signal.c:2490 [inline]
 get_signal+0xc0b/0x1290 kernel/signal.c:2635
 do_signal+0x2b/0x840 arch/x86/kernel/signal.c:784
 exit_to_usermode_loop+0x24a/0x2c0 arch/x86/entry/common.c:161
 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:279 [inline]
 do_syscall_64+0x38b/0x3b0 arch/x86/entry/common.c:305
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8881257f2090 of 8 bytes by task 15378 on cpu 1:
 ptrace_check_attach+0xa3/0x260 kernel/ptrace.c:242
 __do_sys_ptrace kernel/ptrace.c:1272 [inline]
 __se_sys_ptrace kernel/ptrace.c:1242 [inline]
 __x64_sys_ptrace+0x102/0x270 kernel/ptrace.c:1242
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 15378 Comm: syz-executor.4 Not tainted 5.7.0-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: 15378 Comm: syz-executor.4 Not tainted 5.7.0-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/0x1a kernel/kcsan/report.c:626
 kcsan_setup_watchpoint+0x3fb/0x440 kernel/kcsan/core.c:519
 ptrace_check_attach+0xa3/0x260 kernel/ptrace.c:242
 __do_sys_ptrace kernel/ptrace.c:1272 [inline]
 __se_sys_ptrace kernel/ptrace.c:1242 [inline]
 __x64_sys_ptrace+0x102/0x270 kernel/ptrace.c:1242
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45ca59
Code: 0d b7 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 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fb9a05b6c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000065
RAX: ffffffffffffffda RBX: 00000000004fb2a0 RCX: 000000000045ca59
RDX: 0000000000000000 RSI: 00000000000001be RDI: 0000000000000018
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000881 R14: 00000000004cb68f R15: 00007fb9a05b76d4
Kernel Offset: disabled
Rebooting in 86400 seconds..