From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Jiri Olsa <olsajiri@gmail.com>
Cc: bpf@vger.kernel.org, Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
John Fastabend <john.fastabend@gmail.com>,
Andrii Nakryiko <andrii@kernel.org>,
Martin KaFai Lau <martin.lau@linux.dev>,
Song Liu <song@kernel.org>, Yonghong Song <yhs@fb.com>,
KP Singh <kpsingh@kernel.org>,
Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>,
Kui-Feng Lee <kuifeng@fb.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH 2/2] bpf: Assign bpf_tramp_run_ctx::saved_run_ctx before recursion check.
Date: Fri, 1 Sep 2023 16:19:08 +0200 [thread overview]
Message-ID: <20230901141908.vMoXrBK6@linutronix.de> (raw)
In-Reply-To: <ZPHxAbQDzZVNyXBL@krava>
On 2023-09-01 16:13:04 [+0200], Jiri Olsa wrote:
> On Wed, Aug 30, 2023 at 10:04:05AM +0200, Sebastian Andrzej Siewior wrote:
> > __bpf_prog_enter() assigns bpf_tramp_run_ctx::saved_run_ctx before
>
> I guess you meant __bpf_prog_enter_recur right?
>
> > performing the recursion check which means in case of a recursion
> > __bpf_prog_exit() uses the previously set
> > bpf_tramp_run_ctx::saved_run_ctx value.
> >
> > __bpf_prog_enter_sleepable() assigns bpf_tramp_run_ctx::saved_run_ctx
>
> __bpf_prog_enter_sleepable_recur ?
>
> > after the recursion check which means in case of a recursion
> > __bpf_prog_exit_sleepable() uses an uninitialized value.
> > This does not look right. If I read the entry trampoline code right,
> > then bpf_tramp_run_ctx isn't initialized upfront.
> >
> > Align __bpf_prog_enter_sleepable() with __bpf_prog_enter() and set
>
> ditto
Yes, in both cases. The ones I mentioned have no conditionals. Sorry.
> jirka
Sebastian
next prev parent reply other threads:[~2023-09-01 14:19 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-30 8:04 [PATCH 0/2] bpf: Recursion detection related fixes Sebastian Andrzej Siewior
2023-08-30 8:04 ` [PATCH 1/2] bpf: Invoke __bpf_prog_exit_sleepable_recur() on recursion in kern_sys_bpf() Sebastian Andrzej Siewior
2023-09-01 14:02 ` Jiri Olsa
2023-08-30 8:04 ` [PATCH 2/2] bpf: Assign bpf_tramp_run_ctx::saved_run_ctx before recursion check Sebastian Andrzej Siewior
2023-09-01 14:13 ` Jiri Olsa
2023-09-01 14:19 ` Sebastian Andrzej Siewior [this message]
2023-09-06 8:52 ` Daniel Borkmann
2023-09-07 10:12 ` Sebastian Andrzej Siewior
2023-09-06 9:00 ` [PATCH 0/2] bpf: Recursion detection related fixes patchwork-bot+netdevbpf
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