linux-kernel - [syzbot] [net?] KMSAN: uninit-value in unix

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Message-ID: <6854946c.a00a0220.137b3.001e.GAE@google.com>
Date: Thu, 19 Jun 2025 15:51:24 -0700
From: syzbot <syzbot+d0fba1a09f8c1e3ddda5@...kaller.appspotmail.com>
To: davem@...emloft.net, edumazet@...gle.com, horms@...nel.org, 
	kuba@...nel.org, kuniyu@...gle.com, linux-kernel@...r.kernel.org, 
	netdev@...r.kernel.org, pabeni@...hat.com, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [net?] KMSAN: uninit-value in unix_create1

Hello,

syzbot found the following issue on:

HEAD commit:    08215f5486ec Merge tag 'kbuild-fixes-v6.16' of git://git.k..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11b765d4580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=61539536677af51c
dashboard link: https://syzkaller.appspot.com/bug?extid=d0fba1a09f8c1e3ddda5
compiler:       Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/01c395d764eb/disk-08215f54.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/15fc58e6441d/vmlinux-08215f54.xz
kernel image: https://storage.googleapis.com/syzbot-assets/dbd5ac78ef83/bzImage-08215f54.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d0fba1a09f8c1e3ddda5@...kaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in hlist_add_head include/linux/list.h:1025 [inline]
BUG: KMSAN: uninit-value in __sk_add_node include/net/sock.h:853 [inline]
BUG: KMSAN: uninit-value in sk_add_node include/net/sock.h:859 [inline]
BUG: KMSAN: uninit-value in __unix_insert_socket net/unix/af_unix.c:380 [inline]
BUG: KMSAN: uninit-value in unix_insert_unbound_socket net/unix/af_unix.c:403 [inline]
BUG: KMSAN: uninit-value in unix_create1+0x973/0xbc0 net/unix/af_unix.c:1085
 hlist_add_head include/linux/list.h:1025 [inline]
 __sk_add_node include/net/sock.h:853 [inline]
 sk_add_node include/net/sock.h:859 [inline]
 __unix_insert_socket net/unix/af_unix.c:380 [inline]
 unix_insert_unbound_socket net/unix/af_unix.c:403 [inline]
 unix_create1+0x973/0xbc0 net/unix/af_unix.c:1085
 unix_create+0x193/0x220 net/unix/af_unix.c:1127
 __sock_create+0x764/0xf60 net/socket.c:1541
 sock_create net/socket.c:1599 [inline]
 __sys_socketpair+0x329/0xe30 net/socket.c:1746
 __do_sys_socketpair net/socket.c:1799 [inline]
 __se_sys_socketpair net/socket.c:1796 [inline]
 __x64_sys_socketpair+0xc0/0x150 net/socket.c:1796
 x64_sys_call+0x2b98/0x3db0 arch/x86/include/generated/asm/syscalls_64.h:54
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:4154 [inline]
 slab_alloc_node mm/slub.c:4197 [inline]
 __do_kmalloc_node mm/slub.c:4327 [inline]
 __kvmalloc_node_noprof+0xa36/0x1530 mm/slub.c:5015
 kvmalloc_array_node_noprof include/linux/slab.h:1065 [inline]
 unix_net_init+0x19d/0x430 net/unix/af_unix.c:3746
 ops_init+0x2b3/0x9f0 net/core/net_namespace.c:138
 __register_pernet_operations net/core/net_namespace.c:1284 [inline]
 register_pernet_operations+0x649/0xfa0 net/core/net_namespace.c:1361
 register_pernet_subsys+0x5b/0xa0 net/core/net_namespace.c:1402
 af_unix_init+0x12c/0x200 net/unix/af_unix.c:3882
 do_one_initcall+0x237/0xb60 init/main.c:1274
 do_initcall_level+0x166/0x380 init/main.c:1336
 do_initcalls+0x1b5/0x350 init/main.c:1352
 do_basic_setup+0x22/0x30 init/main.c:1371
 kernel_init_freeable+0x2fe/0x4d0 init/main.c:1584
 kernel_init+0x2f/0x5e0 init/main.c:1474
 ret_from_fork+0x1e0/0x310 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

CPU: 1 UID: 0 PID: 5445 Comm: dhcpcd Tainted: G        W           6.16.0-rc1-syzkaller-00239-g08215f5486ec #0 PREEMPT(undef) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
=====================================================


---
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