From: syzbot <syzbot+2860e75836a08b172755@syzkaller.appspotmail.com>
To: listout@listout.xyz
Cc: davem@davemloft.net, edumazet@google.com, horms@kernel.org,
kuba@kernel.org, linux-hams@vger.kernel.org,
linux-kernel@vger.kernel.org, listout@listout.xyz,
netdev@vger.kernel.org, pabeni@redhat.com,
syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [hams?] KASAN: slab-use-after-free Read in nr_add_node
Date: Sat, 18 Oct 2025 22:10:12 -0700 [thread overview]
Message-ID: <68f472b4.050a0220.1186a4.0526.GAE@google.com> (raw)
In-Reply-To: <b5ontczz4n4gthaaeg6kfav3yaf25u4eax3uo46r44rcwap5hd@fpxvlsznasjp>
> On 18.10.2025 13:37, syzbot wrote:
>> syzbot has found a reproducer for the following issue on:
>>
>> HEAD commit: f406055cb18c Merge tag 'arm64-fixes' of git://git.kernel.o..
>> git tree: upstream
>> console output: https://syzkaller.appspot.com/x/log.txt?x=11cf767c580000
>> kernel config: https://syzkaller.appspot.com/x/.config?x=f3e7b5a3627a90dd
>> dashboard link: https://syzkaller.appspot.com/bug?extid=2860e75836a08b172755
>> compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
>> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=155f1de2580000
>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12b6b52f980000
>>
>> Downloadable assets:
>> disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-f406055c.raw.xz
>> vmlinux: https://storage.googleapis.com/syzbot-assets/a4db2a99bfb1/vmlinux-f406055c.xz
>> kernel image: https://storage.googleapis.com/syzbot-assets/91d1ca420bac/bzImage-f406055c.xz
>>
>> IMPORTANT: if you fix the issue, please add the following tag to the commit:
>> Reported-by: syzbot+2860e75836a08b172755@syzkaller.appspotmail.com
>>
>> ==================================================================
>> BUG: KASAN: slab-use-after-free in nr_add_node+0x25db/0x2c00 net/netrom/nr_route.c:248
>> Read of size 4 at addr ffff888054b8cc30 by task syz.3.7839/22393
>
> #syz test linux-next
want either no args or 2 args (repo, branch), got 1
>
> diff --git a/net/netrom/nr_route.c b/net/netrom/nr_route.c
> index b94cb2ffbaf8..5fa7d9febbbb 100644
> --- a/net/netrom/nr_route.c
> +++ b/net/netrom/nr_route.c
> @@ -245,7 +245,9 @@ static int __must_check nr_add_node(ax25_address *nr, const char *mnemonic,
> nr_node->routes[2].neighbour->count--;
> nr_neigh_put(nr_node->routes[2].neighbour);
>
> - if (nr_node->routes[2].neighbour->count == 0 && !nr_node->routes[2].neighbour->locked)
> + if (nr_node->routes[2].neighbour &&
> + nr_node->routes[2].neighbour->count == 0 &&
> + !nr_node->routes[2].neighbour->locked)
> nr_remove_neigh(nr_node->routes[2].neighbour);
>
> nr_node->routes[2].quality = quality;
>
> --
> Regards,
> listout
next prev parent reply other threads:[~2025-10-19 5:10 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-25 16:35 [syzbot] [hams?] KASAN: slab-use-after-free Read in nr_add_node syzbot
2025-10-18 20:37 ` syzbot
2025-10-19 5:02 ` Brahmajit Das
2025-10-19 5:21 ` syzbot
2025-10-19 5:10 ` Brahmajit Das
2025-10-19 5:10 ` syzbot [this message]
2025-10-20 8:13 ` [PATCH] netrom: Prevent race conditions between multiple add route Lizhi Xu
2025-10-20 10:10 ` Dan Carpenter
2025-10-20 11:02 ` [PATCH V2] " Lizhi Xu
2025-10-20 12:25 ` Dan Carpenter
2025-10-20 12:33 ` Dan Carpenter
2025-10-20 12:57 ` Dan Carpenter
2025-10-20 13:34 ` Lizhi Xu
2025-10-20 13:49 ` Lizhi Xu
2025-10-20 17:59 ` Dan Carpenter
2025-10-21 2:05 ` Lizhi Xu
2025-10-21 6:36 ` Dan Carpenter
2025-10-21 8:34 ` Lizhi Xu
2025-10-21 8:35 ` [PATCH V3] netrom: Prevent race conditions between neighbor operations Lizhi Xu
2025-10-23 11:44 ` Paolo Abeni
2025-10-23 11:54 ` Eric Dumazet
2025-10-23 12:41 ` Lizhi Xu
2025-10-23 13:50 ` [PATCH V4] netrom: Preventing the use of abnormal neighbor Lizhi Xu
2025-10-28 14:13 ` Paolo Abeni
2025-10-29 2:59 ` Lizhi Xu
2025-11-13 6:33 ` Lizhi Xu
2025-10-24 10:45 ` [PATCH V3] netrom: Prevent race conditions between neighbor operations Dan Carpenter
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