From: Jakub Kicinski <kuba@kernel•org>
To: Octavian Purdila <tavip@google•com>
Cc: davem@davemloft•net, edumazet@google•com, pabeni@redhat•com,
horms@kernel•org, ast@kernel•org, daniel@iogearbox•net,
hawk@kernel•org, john.fastabend@gmail•com, sdf@fomichev•me,
uniyu@google•com, ahmed.zaki@intel•com,
aleksander.lobakin@intel•com, toke@redhat•com,
lorenzo@kernel•org, netdev@vger•kernel.org, bpf@vger•kernel.org,
syzbot+ff145014d6b0ce64a173@syzkaller•appspotmail.com
Subject: Re: [PATCH net] xdp: use multi-buff only if receive queue supports page pool
Date: Wed, 24 Sep 2025 17:09:14 -0700 [thread overview]
Message-ID: <20250924170914.20aac680@kernel.org> (raw)
In-Reply-To: <20250924060843.2280499-1-tavip@google.com>
On Wed, 24 Sep 2025 06:08:42 +0000 Octavian Purdila wrote:
> When a BPF program that supports BPF_F_XDP_HAS_FRAGS is issuing
> bpf_xdp_adjust_tail and a large packet is injected via /dev/net/tun a
> crash occurs due to detecting a bad page state (page_pool leak).
>
> This is because xdp_buff does not record the type of memory and
> instead relies on the netdev receive queue xdp info. Since the TUN/TAP
> driver is using a MEM_TYPE_PAGE_SHARED memory model buffer, shrinking
> will eventually call page_frag_free. But with current multi-buff
> support for BPF_F_XDP_HAS_FRAGS programs buffers are allocated via the
> page pool.
>
> To fix this issue check that the receive queue memory mode is of
> MEM_TYPE_PAGE_POOL before using multi-buffs.
This can also happen on veth, right? And veth re-stamps the Rx queues.
next prev parent reply other threads:[~2025-09-25 0:09 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-24 6:08 [PATCH net] xdp: use multi-buff only if receive queue supports page pool Octavian Purdila
2025-09-25 0:09 ` Jakub Kicinski [this message]
2025-09-25 7:53 ` Octavian Purdila
2025-09-25 9:42 ` Maciej Fijalkowski
2025-09-26 2:12 ` Jakub Kicinski
2025-09-26 7:33 ` Octavian Purdila
2025-09-26 11:24 ` Maciej Fijalkowski
2025-09-26 19:40 ` Jakub Kicinski
2025-09-30 0:01 ` Octavian Purdila
2025-09-30 17:41 ` Jakub Kicinski
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