syzbot

==================================================================
BUG: KCSAN: data-race in copy_creds / init_peercred

write to 0xffff888121e1c998 of 4 bytes by task 1146 on cpu 0:
 get_cred include/linux/cred.h:253 [inline]
 copy_creds+0x206/0x340 kernel/cred.c:345
 copy_process+0x926/0x3b50 kernel/fork.c:1884
 _do_fork+0xfe/0x6e0 kernel/fork.c:2366
 __do_sys_clone kernel/fork.c:2521 [inline]
 __se_sys_clone kernel/fork.c:2502 [inline]
 __x64_sys_clone+0x12b/0x160 kernel/fork.c:2502
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff888121e1c998 of 4 bytes by task 1155 on cpu 1:
 get_cred include/linux/cred.h:253 [inline]
 init_peercred+0x108/0x150 net/unix/af_unix.c:595
 unix_socketpair+0x8c/0x110 net/unix/af_unix.c:1399
 __sys_socketpair+0x227/0x450 net/socket.c:1586
 __do_sys_socketpair net/socket.c:1622 [inline]
 __se_sys_socketpair net/socket.c:1619 [inline]
 __x64_sys_socketpair+0x5e/0x80 net/socket.c:1619
 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: 1 PID: 1155 Comm: syz-executor.0 Not tainted 5.4.0-rc6+ #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: 1155 Comm: syz-executor.0 Not tainted 5.4.0-rc6+ #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+0xf5/0x159 lib/dump_stack.c:113
 panic+0x210/0x640 kernel/panic.c:221
 kcsan_report.cold+0xc/0xe kernel/kcsan/report.c:302
 kcsan_setup_watchpoint+0x3fe/0x410 kernel/kcsan/core.c:357
 check_access kernel/kcsan/core.c:409 [inline]
 __tsan_unaligned_write4+0x143/0x1f0 kernel/kcsan/core.c:529
 get_cred include/linux/cred.h:253 [inline]
 init_peercred+0x108/0x150 net/unix/af_unix.c:595
 unix_socketpair+0x8c/0x110 net/unix/af_unix.c:1399
 __sys_socketpair+0x227/0x450 net/socket.c:1586
 __do_sys_socketpair net/socket.c:1622 [inline]
 __se_sys_socketpair net/socket.c:1619 [inline]
 __x64_sys_socketpair+0x5e/0x80 net/socket.c:1619
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45a219
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:00007f3d67b49c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000035
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 000000000045a219
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001
RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000020000000 R11: 0000000000000246 R12: 00007f3d67b4a6d4
R13: 00000000004c981f R14: 00000000004e1338 R15: 00000000ffffffff
Kernel Offset: disabled
Rebooting in 86400 seconds..