From: Roman Gushchin <guro@fb.com>
To: Daniel Borkmann <daniel@iogearbox.net>
Cc: "ast@kernel.org" <ast@kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"bpf@vger.kernel.org" <bpf@vger.kernel.org>,
"Martin Lau" <kafai@fb.com>
Subject: Re: [PATCH bpf] bpf: Fix cgroup local storage prog tracking
Date: Tue, 17 Dec 2019 18:14:00 +0000 [thread overview]
Message-ID: <20191217181356.GA5770@localhost.localdomain> (raw)
In-Reply-To: <1471c69eca3022218666f909bc927a92388fd09e.1576580332.git.daniel@iogearbox.net>
On Tue, Dec 17, 2019 at 01:28:16PM +0100, Daniel Borkmann wrote:
> Recently noticed that we're tracking programs related to local storage maps
> through their prog pointer. This is a wrong assumption since the prog pointer
> can still change throughout the verification process, for example, whenever
> bpf_patch_insn_single() is called.
Oh, I didn't know it.
>
> Therefore, the prog pointer that was assigned via bpf_cgroup_storage_assign()
> is not guaranteed to be the same as we pass in bpf_cgroup_storage_release()
> and the map would therefore remain in busy state forever. Fix this by using
> the prog's aux pointer which is stable throughout verification and beyond.
>
> Fixes: de9cbbaadba5 ("bpf: introduce cgroup storage maps")
> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
> Cc: Roman Gushchin <guro@fb.com>
> Cc: Martin KaFai Lau <kafai@fb.com>
Acked-by: Roman Gushchin <guro@fb.com>
Thank you, Daniel!
prev parent reply other threads:[~2019-12-17 18:14 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-17 12:28 [PATCH bpf] bpf: Fix cgroup local storage prog tracking Daniel Borkmann
2019-12-17 17:32 ` Alexei Starovoitov
2019-12-17 18:14 ` Roman Gushchin [this message]
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