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Date:   Tue, 05 Dec 2023 10:25:31 -0800
Message-ID: <0000000000001b9bed060bc75cbc@google.com>
Subject: [syzbot] [net?] KMSAN: uninit-value in __llc_lookup_established
From:   syzbot <syzbot+b5ad66046b913bc04c6f@syzkaller.appspotmail.com>
To:     davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
        linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
        pabeni@redhat.com, syzkaller-bugs@googlegroups.com
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Hello,

syzbot found the following issue on:

HEAD commit:    1c41041124bd Merge tag 'i3c/for-6.7' of git://git.kernel.o..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=10429eeb680000
kernel config:  https://syzkaller.appspot.com/x/.config?x=956549bd1d1e9efd
dashboard link: https://syzkaller.appspot.com/bug?extid=b5ad66046b913bc04c6f
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=12b6a00f680000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=121471ef680000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/20fd86e677f1/disk-1c410411.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ccd39cb0b7b6/vmlinux-1c410411.xz
kernel image: https://storage.googleapis.com/syzbot-assets/156fc60f97bc/bzImage-1c410411.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b5ad66046b913bc04c6f@syzkaller.appspotmail.com

syz-executor994 uses obsolete (PF_INET,SOCK_PACKET)
=====================================================
BUG: KMSAN: uninit-value in __llc_lookup_established+0xe9d/0xf90
 __llc_lookup_established+0xe9d/0xf90
 __llc_lookup net/llc/llc_conn.c:611 [inline]
 llc_conn_handler+0x4bd/0x1360 net/llc/llc_conn.c:791
 llc_rcv+0xfbb/0x14a0 net/llc/llc_input.c:206
 __netif_receive_skb_one_core net/core/dev.c:5527 [inline]
 __netif_receive_skb+0x1a6/0x5a0 net/core/dev.c:5641
 netif_receive_skb_internal net/core/dev.c:5727 [inline]
 netif_receive_skb+0x58/0x660 net/core/dev.c:5786
 tun_rx_batched+0x3ee/0x980 drivers/net/tun.c:1555
 tun_get_user+0x53af/0x66d0 drivers/net/tun.c:2002
 tun_chr_write_iter+0x3af/0x5d0 drivers/net/tun.c:2048
 call_write_iter include/linux/fs.h:2020 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x8ef/0x1490 fs/read_write.c:584
 ksys_write+0x20f/0x4c0 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __x64_sys_write+0x93/0xd0 fs/read_write.c:646
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

Local variable daddr created at:
 llc_conn_handler+0x53/0x1360 net/llc/llc_conn.c:783
 llc_rcv+0xfbb/0x14a0 net/llc/llc_input.c:206

CPU: 1 PID: 5004 Comm: syz-executor994 Not tainted 6.6.0-syzkaller-14500-g1c41041124bd #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
=====================================================


---
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