linux-kernel - [syzbot] [sctp?] KMSAN: uninit-value in __sctp_v6_cmp

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Message-ID: <68adc0a2.050a0220.37038e.00c4.GAE@google.com>
Date: Tue, 26 Aug 2025 07:11:46 -0700
From: syzbot <syzbot+e69f06a0f30116c68056@...kaller.appspotmail.com>
To: davem@...emloft.net, edumazet@...gle.com, horms@...nel.org, 
	kuba@...nel.org, linux-kernel@...r.kernel.org, linux-sctp@...r.kernel.org, 
	lucien.xin@...il.com, marcelo.leitner@...il.com, netdev@...r.kernel.org, 
	pabeni@...hat.com, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [sctp?] KMSAN: uninit-value in __sctp_v6_cmp_addr (2)

Hello,

syzbot found the following issue on:

HEAD commit:    69fd6b99b8f8 Merge tag 'perf_urgent_for_v6.17_rc3' of git:..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10adec42580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=6ccfdce02093e91f
dashboard link: https://syzkaller.appspot.com/bug?extid=e69f06a0f30116c68056
compiler:       Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=130d8462580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10bfb862580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ce22f4296138/disk-69fd6b99.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/36a2af954ef6/vmlinux-69fd6b99.xz
kernel image: https://storage.googleapis.com/syzbot-assets/594a8181f23a/bzImage-69fd6b99.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e69f06a0f30116c68056@...kaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in __sctp_v6_cmp_addr+0x887/0x8c0 net/sctp/ipv6.c:649
 __sctp_v6_cmp_addr+0x887/0x8c0 net/sctp/ipv6.c:649
 sctp_inet6_cmp_addr+0x4f2/0x510 net/sctp/ipv6.c:983
 sctp_bind_addr_conflict+0x22a/0x3b0 net/sctp/bind_addr.c:390
 sctp_get_port_local+0x21eb/0x2440 net/sctp/socket.c:8452
 sctp_get_port net/sctp/socket.c:8523 [inline]
 sctp_listen_start net/sctp/socket.c:8567 [inline]
 sctp_inet_listen+0x710/0xfd0 net/sctp/socket.c:8636
 __sys_listen_socket net/socket.c:1912 [inline]
 __sys_listen net/socket.c:1927 [inline]
 __do_sys_listen net/socket.c:1932 [inline]
 __se_sys_listen net/socket.c:1930 [inline]
 __x64_sys_listen+0x343/0x4c0 net/socket.c:1930
 x64_sys_call+0x271d/0x3e20 arch/x86/include/generated/asm/syscalls_64.h:51
 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

Local variable t.i created at:
 __do_sys_futex kernel/futex/syscalls.c:165 [inline]
 __se_sys_futex+0x4d/0x740 kernel/futex/syscalls.c:160
 __x64_sys_futex+0x114/0x1a0 kernel/futex/syscalls.c:160

CPU: 1 UID: 0 PID: 6089 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(none) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
=====================================================


---
This report is generated by a bot. It may contain errors.
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