netdev - [syzbot] [net?] KMSAN: uninit-value in macsec_handle

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Message-ID: <6909e39f.050a0220.98a6.00ac.GAE@google.com>
Date: Tue, 04 Nov 2025 03:29:35 -0800
From: syzbot <syzbot+0e665e4b99cb925286a0@...kaller.appspotmail.com>
To: andrew+netdev@...n.ch, davem@...emloft.net, edumazet@...gle.com, 
	kuba@...nel.org, linux-kernel@...r.kernel.org, netdev@...r.kernel.org, 
	pabeni@...hat.com, sd@...asysnail.net, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [net?] KMSAN: uninit-value in macsec_handle_frame (2)

Hello,

syzbot found the following issue on:

HEAD commit:    6fab32bb6508 MAINTAINERS: add Mark Brown as a linux-next m..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=100c2614580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=8e9863e17aadf7a1
dashboard link: https://syzkaller.appspot.com/bug?extid=0e665e4b99cb925286a0
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/df4a4033fe11/disk-6fab32bb.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/cc3ed0072d4f/vmlinux-6fab32bb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/58cfbb151380/bzImage-6fab32bb.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0e665e4b99cb925286a0@...kaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in macsec_handle_frame+0x2f6/0x5410 drivers/net/macsec.c:1148
 macsec_handle_frame+0x2f6/0x5410 drivers/net/macsec.c:1148
 __netif_receive_skb_core+0x2043/0x7150 net/core/dev.c:5966
 __netif_receive_skb_one_core net/core/dev.c:6077 [inline]
 __netif_receive_skb+0xcc/0xac0 net/core/dev.c:6192
 process_backlog+0x485/0xa00 net/core/dev.c:6544
 __napi_poll+0xdd/0x8a0 net/core/dev.c:7594
 napi_poll net/core/dev.c:7657 [inline]
 net_rx_action+0xbc8/0x1c30 net/core/dev.c:7784
 handle_softirqs+0x169/0x6e0 kernel/softirq.c:622
 __do_softirq+0x14/0x1b kernel/softirq.c:656
 do_softirq+0x99/0x100 kernel/softirq.c:523
 __local_bh_enable_ip+0xa1/0xb0 kernel/softirq.c:450
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 netif_rx+0xdb/0x3f0 net/core/dev.c:5647
 pn_send+0x95b/0xb80 net/phonet/af_phonet.c:185
 pn_skb_send+0x462/0xa70 net/phonet/af_phonet.c:272
 pipe_handler_request net/phonet/pep.c:144 [inline]
 pep_sock_connect+0x2af/0x490 net/phonet/pep.c:894
 pn_socket_connect+0x576/0xd10 net/phonet/socket.c:255
 __sys_connect_file net/socket.c:2102 [inline]
 __sys_connect+0x51a/0x680 net/socket.c:2121
 __do_sys_connect net/socket.c:2127 [inline]
 __se_sys_connect net/socket.c:2124 [inline]
 __x64_sys_connect+0x95/0x100 net/socket.c:2124
 x64_sys_call+0x3744/0x3e30 arch/x86/include/generated/asm/syscalls_64.h:43
 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

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:4969 [inline]
 slab_alloc_node mm/slub.c:5272 [inline]
 kmem_cache_alloc_node_noprof+0x989/0x16b0 mm/slub.c:5324
 kmalloc_reserve+0x13c/0x4b0 net/core/skbuff.c:579
 __alloc_skb+0x347/0x7d0 net/core/skbuff.c:670
 alloc_skb include/linux/skbuff.h:1383 [inline]
 pn_raw_send+0x59/0x510 net/phonet/af_phonet.c:207
 send_reset_indications+0x139/0x1c0 net/phonet/af_phonet.c:344
 phonet_rcv+0x1478/0x1830 net/phonet/af_phonet.c:409
 __netif_receive_skb_one_core net/core/dev.c:6079 [inline]
 __netif_receive_skb+0x477/0xac0 net/core/dev.c:6192
 process_backlog+0x485/0xa00 net/core/dev.c:6544
 __napi_poll+0xdd/0x8a0 net/core/dev.c:7594
 napi_poll net/core/dev.c:7657 [inline]
 net_rx_action+0xbc8/0x1c30 net/core/dev.c:7784
 handle_softirqs+0x169/0x6e0 kernel/softirq.c:622
 __do_softirq+0x14/0x1b kernel/softirq.c:656

CPU: 0 UID: 0 PID: 6693 Comm: syz.0.173 Tainted: G        W           syzkaller #0 PREEMPT(none) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
=====================================================


---
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