From: Jakub Kicinski <kuba@kernel.org>
To: Edward Adam Davis <eadavis@qq.com>
Cc: syzbot+ci3edb9412aeb2e703@syzkaller.appspotmail.com,
davem@davemloft.net, edumazet@google.com, eperezma@redhat.com,
horms@kernel.org, jasowang@redhat.com, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org, mst@redhat.com,
netdev@vger.kernel.org, pabeni@redhat.com, sgarzare@redhat.com,
stefanha@redhat.com, syzbot@lists.linux.dev,
syzbot@syzkaller.appspotmail.com,
syzkaller-bugs@googlegroups.com, virtualization@lists.linux.dev,
xuanzhuo@linux.alibaba.com
Subject: Re: [PATCH Next V2] net: restore the iterator to its original state when an error occurs
Date: Fri, 28 Nov 2025 09:39:46 -0800 [thread overview]
Message-ID: <20251128093946.18c645c6@kernel.org> (raw)
In-Reply-To: <tencent_BA768766163C533724966E36344AAE754709@qq.com>
On Fri, 28 Nov 2025 21:35:57 +0800 Edward Adam Davis wrote:
> In zerocopy_fill_skb_from_iter(), if two copy operations are performed
> and the first one succeeds while the second one fails, it returns a
> failure but the count in iterator has already been decremented due to
> the first successful copy. This ultimately affects the local variable
> rest_len in virtio_transport_send_pkt_info(), causing the remaining
> count in rest_len to be greater than the actual iterator count. As a
> result, packet sending operations continue even when the iterator count
> is zero, which further leads to skb->len being 0 and triggers the warning
> reported by syzbot [1].
Please follow the subsystem guidelines for posting patches:
https://www.kernel.org/doc/html/next/process/maintainer-netdev.html
Your patch breaks zerocopy tests.
next prev parent reply other threads:[~2025-11-28 17:39 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-28 1:44 [syzbot] [kvm?] [net?] [virt?] WARNING in virtio_transport_send_pkt_info (2) syzbot
2025-11-28 4:34 ` Edward Adam Davis
2025-11-28 6:47 ` syzbot
2025-11-28 7:55 ` Edward Adam Davis
2025-11-28 9:02 ` syzbot
2025-11-28 8:09 ` Edward Adam Davis
2025-11-28 9:18 ` syzbot
2025-11-28 8:41 ` [PATCH Next] net: restore the iterator to its original state when an error occurs Edward Adam Davis
2025-11-28 13:05 ` [syzbot ci] " syzbot ci
2025-11-28 13:35 ` [PATCH Next V2] " Edward Adam Davis
2025-11-28 17:39 ` Jakub Kicinski [this message]
2025-12-01 3:41 ` Edward Adam Davis
2025-12-01 19:15 ` Jakub Kicinski
2025-12-03 15:55 ` [syzbot] [kvm?] [net?] [virt?] WARNING in virtio_transport_send_pkt_info (2) Edward Adam Davis
2025-12-03 16:27 ` syzbot
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