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AJvYcCUIdRV7ZxZSmB+TuU1Ylduf/6KubkMYdbNsgHR+Uw98huBP7CRNy07KEDHXdpfKFUVchNyxk2AgLe0gNIc=@vger.kernel.org X-Gm-Message-State: AOJu0YyeqEX9xniGwOmvofPVfC9LBtrbxx/2d7+Q3ZzTvh6rMhREj+pV Gc8BF02U9E7pXXuHWb0bf8kk77C38ux6ZAOYQk4ZyaIK+aXwCVvwPyT/k1f8SPoEQKX7FtF7Iah qpFK/AiMt3wspst20a55FyaNmp7sRkdfBrJ146vem/rg24FULSHTRllPboys= X-Google-Smtp-Source: AGHT+IEJaULw+WXFDA4gqC5wuVExSj4Wt7KVfriwzo/9lrYIyylU4A1FdxsH2XMSg5Xxz2HM8ohkbsLjvlv8JTTmMac0AAWHGKUD Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6602:641c:b0:940:d475:315f with SMTP id ca18e2360f4ac-940d475355amr126073439f.11.1760850612729; Sat, 18 Oct 2025 22:10:12 -0700 (PDT) Date: Sat, 18 Oct 2025 22:10:12 -0700 In-Reply-To: X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <68f472b4.050a0220.1186a4.0526.GAE@google.com> Subject: Re: [syzbot] [hams?] KASAN: slab-use-after-free Read in nr_add_node From: syzbot 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 Content-Type: text/plain; charset="UTF-8" > 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