xt_TCPMSS: Only works on TCP SYN packets
==================================================================
BUG: KCSAN: data-race in find_alive_thread / get_signal

write to 0xffff888097cb1024 of 4 bytes by task 9412 on cpu 1:
 get_signal+0x7a2/0x1290 kernel/signal.c:2714
 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+0x190/0x1c0 arch/x86/entry/common.c:195
 swapgs_restore_regs_and_return_to_usermode+0x0/0x40

read to 0xffff888097cb1024 of 4 bytes by task 9414 on cpu 0:
 find_alive_thread+0xd5/0x120 kernel/exit.c:495
 find_new_reaper kernel/exit.c:544 [inline]
 forget_original_parent kernel/exit.c:619 [inline]
 exit_notify kernel/exit.c:652 [inline]
 do_exit+0x7f5/0x1880 kernel/exit.c:822
 do_group_exit+0xae/0x1a0 kernel/exit.c:899
 __do_sys_exit_group kernel/exit.c:910 [inline]
 __se_sys_exit_group kernel/exit.c:908 [inline]
 __x64_sys_exit_group+0x2b/0x30 kernel/exit.c:908
 do_syscall_64+0xc7/0x390 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 9414 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: 0 PID: 9414 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
 find_alive_thread+0xd5/0x120 kernel/exit.c:495
 find_new_reaper kernel/exit.c:544 [inline]
 forget_original_parent kernel/exit.c:619 [inline]
 exit_notify kernel/exit.c:652 [inline]
 do_exit+0x7f5/0x1880 kernel/exit.c:822
 do_group_exit+0xae/0x1a0 kernel/exit.c:899
 __do_sys_exit_group kernel/exit.c:910 [inline]
 __se_sys_exit_group kernel/exit.c:908 [inline]
 __x64_sys_exit_group+0x2b/0x30 kernel/exit.c:908
 do_syscall_64+0xc7/0x390 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45c879
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:00007fc03b225688 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 000000000000000b RCX: 000000000045c879
RDX: 000000000045c879 RSI: 00007fc03b2256c0 RDI: 000000000000000b
RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000288 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000a37 R14: 00000000004cce16 R15: 000000000076bf0c
Kernel Offset: disabled
Rebooting in 86400 seconds..