linux-kernel - Re: [syzbot] [tipc?] KMSAN: uninit-value in tipc

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Message-ID: <690db9fe.a70a0220.22f260.002f.GAE@google.com>
Date: Fri, 07 Nov 2025 01:21:02 -0800
From: syzbot <syzbot+9a4fbb77c9d4aacd3388@...kaller.appspotmail.com>
To: hariconscious@...il.com, linux-kernel@...r.kernel.org, 
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [tipc?] KMSAN: uninit-value in tipc_rcv (2)

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
kernel BUG in tipc_buf_acquire

tipc: Started in network mode
tipc: Node identity 5e9377e8cc82, cluster identity 4711
tipc: tipc_buf_acquire
skbuff: skb_over_panic: text:ffffffff8fe53c01 len:76 put:76 head:0000000000000000 data:00000000000000d0 tail:0x11c end:0x0 dev:<NULL>
------------[ cut here ]------------
kernel BUG at net/core/skbuff.c:212!
Oops: invalid opcode: 0000 [#1] SMP PTI
CPU: 0 UID: 0 PID: 6600 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(none) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:skb_panic+0x2d3/0x340 net/core/skbuff.c:212
Code: d0 44 8b 45 cc 4c 8b 8d 58 ff ff ff 41 52 ff b5 70 ff ff ff ff b5 68 ff ff ff ff b5 60 ff ff ff e8 d2 5d ee ff 48 83 c4 20 90 <0f> 0b e8 c6 8f 69 01 48 83 7d a0 00 0f 84 6a ff ff ff 48 8b 7d c0
RSP: 0018:ffff88801f8cf0e8 EFLAGS: 00010286
RAX: 0000000000000085 RBX: ffff88811718cda0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000002
RBP: ffff88801f8cf1a0 R08: ffffea000000000f R09: 0000000000000000
R10: ffff888237c7e028 R11: ffff88823f278d40 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  00007f26537fe6c0(0000) GS:ffff8881aaf8d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2654574620 CR3: 0000000049ab8000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 skb_over_panic net/core/skbuff.c:217 [inline]
 skb_put+0x1f5/0x250 net/core/skbuff.c:2583
 tipc_buf_acquire+0x141/0x1b0 net/tipc/msg.c:77
 tipc_disc_create+0x12f/0x870 net/tipc/discover.c:359
 tipc_enable_bearer net/tipc/bearer.c:348 [inline]
 __tipc_nl_bearer_enable+0x1f61/0x2a00 net/tipc/bearer.c:1047
 __tipc_nl_compat_doit net/tipc/netlink_compat.c:371 [inline]
 tipc_nl_compat_doit+0x67b/0xa10 net/tipc/netlink_compat.c:393
 tipc_nl_compat_handle net/tipc/netlink_compat.c:-1 [inline]
 tipc_nl_compat_recv+0x1007/0x1670 net/tipc/netlink_compat.c:1321
 genl_family_rcv_msg_doit+0x338/0x3f0 net/netlink/genetlink.c:1115
 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
 genl_rcv_msg+0xacf/0xc10 net/netlink/genetlink.c:1210
 netlink_rcv_skb+0x54d/0x680 net/netlink/af_netlink.c:2552
 genl_rcv+0x41/0x60 net/netlink/genetlink.c:1219
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0xf04/0x12b0 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x10b3/0x1250 net/netlink/af_netlink.c:1896
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg+0x333/0x3d0 net/socket.c:742
 ____sys_sendmsg+0x7e0/0xd80 net/socket.c:2630
 ___sys_sendmsg+0x271/0x3b0 net/socket.c:2684
 __sys_sendmsg net/socket.c:2716 [inline]
 __do_sys_sendmsg net/socket.c:2721 [inline]
 __se_sys_sendmsg net/socket.c:2719 [inline]
 __x64_sys_sendmsg+0x211/0x3e0 net/socket.c:2719
 x64_sys_call+0x1dfd/0x3e30 arch/x86/include/generated/asm/syscalls_64.h:47
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f265458eb69
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f26537fe038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f26547b5fa0 RCX: 00007f265458eb69
RDX: 0000000000000000 RSI: 00002000000002c0 RDI: 0000000000000006
RBP: 00007f2654611df1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f26547b5fa0 R15: 00007ffe744cefd8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:skb_panic+0x2d3/0x340 net/core/skbuff.c:212
Code: d0 44 8b 45 cc 4c 8b 8d 58 ff ff ff 41 52 ff b5 70 ff ff ff ff b5 68 ff ff ff ff b5 60 ff ff ff e8 d2 5d ee ff 48 83 c4 20 90 <0f> 0b e8 c6 8f 69 01 48 83 7d a0 00 0f 84 6a ff ff ff 48 8b 7d c0
RSP: 0018:ffff88801f8cf0e8 EFLAGS: 00010286
RAX: 0000000000000085 RBX: ffff88811718cda0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000002
RBP: ffff88801f8cf1a0 R08: ffffea000000000f R09: 0000000000000000
R10: ffff888237c7e028 R11: ffff88823f278d40 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  00007f26537fe6c0(0000) GS:ffff8881aaf8d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2654574620 CR3: 0000000049ab8000 CR4: 00000000003526f0


Tested on:

commit:         4a0c9b33 Merge tag 'probes-fixes-v6.18-rc4' of git://g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17a79084580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=2901a6a99b67fbcc
dashboard link: https://syzkaller.appspot.com/bug?extid=9a4fbb77c9d4aacd3388
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=107a332f980000