From: Simon Horman <horms@kernel•org>
To: Daniel Borkmann <daniel@iogearbox•net>
Cc: netdev@vger•kernel.org, davem@davemloft•net, pabeni@redhat•com,
kuba@kernel•org, gal@nvidia•com, martin.lau@linux•dev
Subject: Re: [PATCH net-next 1/2] net: Fix skb consume leak in sch_handle_egress
Date: Sat, 26 Aug 2023 09:57:40 +0200 [thread overview]
Message-ID: <20230826075740.GO3523530@kernel.org> (raw)
In-Reply-To: <20230825134946.31083-1-daniel@iogearbox.net>
On Fri, Aug 25, 2023 at 03:49:45PM +0200, Daniel Borkmann wrote:
> Fix a memory leak for the tc egress path with TC_ACT_{STOLEN,QUEUED,TRAP}:
>
> [...]
> unreferenced object 0xffff88818bcb4f00 (size 232):
> comm "softirq", pid 0, jiffies 4299085078 (age 134.028s)
> hex dump (first 32 bytes):
> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> 00 80 70 61 81 88 ff ff 00 41 31 14 81 88 ff ff ..pa.....A1.....
> backtrace:
> [<ffffffff9991b938>] kmem_cache_alloc_node+0x268/0x400
> [<ffffffff9b3d9231>] __alloc_skb+0x211/0x2c0
> [<ffffffff9b3f0c7e>] alloc_skb_with_frags+0xbe/0x6b0
> [<ffffffff9b3bf9a9>] sock_alloc_send_pskb+0x6a9/0x870
> [<ffffffff9b6b3f00>] __ip_append_data+0x14d0/0x3bf0
> [<ffffffff9b6ba24e>] ip_append_data+0xee/0x190
> [<ffffffff9b7e1496>] icmp_push_reply+0xa6/0x470
> [<ffffffff9b7e4030>] icmp_reply+0x900/0xa00
> [<ffffffff9b7e42e3>] icmp_echo.part.0+0x1a3/0x230
> [<ffffffff9b7e444d>] icmp_echo+0xcd/0x190
> [<ffffffff9b7e9566>] icmp_rcv+0x806/0xe10
> [<ffffffff9b699bd1>] ip_protocol_deliver_rcu+0x351/0x3d0
> [<ffffffff9b699f14>] ip_local_deliver_finish+0x2b4/0x450
> [<ffffffff9b69a234>] ip_local_deliver+0x174/0x1f0
> [<ffffffff9b69a4b2>] ip_sublist_rcv_finish+0x1f2/0x420
> [<ffffffff9b69ab56>] ip_sublist_rcv+0x466/0x920
> [...]
>
> I was able to reproduce this via:
>
> ip link add dev dummy0 type dummy
> ip link set dev dummy0 up
> tc qdisc add dev eth0 clsact
> tc filter add dev eth0 egress protocol ip prio 1 u32 match ip protocol 1 0xff action mirred egress redirect dev dummy0
> ping 1.1.1.1
> <stolen>
>
> After the fix, there are no kmemleak reports with the reproducer. This is
> in line with what is also done on the ingress side, and from debugging the
> skb_unref(skb) on dummy xmit and sch_handle_egress() side, it is visible
> that these are two different skbs with both skb_unref(skb) as true. The two
> seen skbs are due to mirred doing a skb_clone() internally as use_reinsert
> is false in tcf_mirred_act() for egress. This was initially reported by Gal.
>
> Fixes: e420bed02507 ("bpf: Add fd-based tcx multi-prog infra with link support")
> Reported-by: Gal Pressman <gal@nvidia•com>
> Signed-off-by: Daniel Borkmann <daniel@iogearbox•net>
> Link: https://lore.kernel.org/bpf/bdfc2640-8f65-5b56-4472-db8e2b161aab@nvidia.com
Reviewed-by: Simon Horman <horms@kernel•org>
next prev parent reply other threads:[~2023-08-26 7:57 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-25 13:49 [PATCH net-next 1/2] net: Fix skb consume leak in sch_handle_egress Daniel Borkmann
2023-08-25 13:49 ` [PATCH net-next 2/2] net: Make consumed action consistent " Daniel Borkmann
2023-08-26 7:58 ` Simon Horman
2023-08-26 7:57 ` Simon Horman [this message]
2023-08-27 13:55 ` [PATCH net-next 1/2] net: Fix skb consume leak " Gal Pressman
2023-08-28 12:55 ` Gal Pressman
2023-08-28 13:05 ` Daniel Borkmann
2023-08-28 9:20 ` patchwork-bot+netdevbpf
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