From: Peter Zijlstra <peterz@infradead.org>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>,
Oleg Nesterov <oleg@redhat.com>,
andrii@kernel.org, mhiramat@kernel.org, jolsa@kernel.org,
rostedt@goodmis.org, linux-kernel@vger.kernel.org,
linux-trace-kernel@vger.kernel.org, bpf <bpf@vger.kernel.org>
Subject: Re: [PATCH v4 0/9] uprobes: misc cleanups/simplifications
Date: Fri, 2 Aug 2024 11:25:28 +0200 [thread overview]
Message-ID: <20240802092528.GF39708@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <CAEf4BzY9diEi2_tHsLxB4Yk-ZAWHT=XJNmagjQtOXc7qShqgrA@mail.gmail.com>
On Thu, Aug 01, 2024 at 02:13:41PM -0700, Andrii Nakryiko wrote:
> Ok, this bisected to:
>
> 675ad74989c2 ("perf/core: Add aux_pause, aux_resume, aux_start_paused")
Adrian, there are at least two obvious bugs there:
- aux_action was key's off of PERF_PMU_CAP_AUX_OUTPUT, which is not
right, that's the capability where events can output to AUX -- aka.
PEBS-to-PT. It should be PERF_PMU_CAP_ITRACE, which is the
PT/CoreSight thing.
- it sets aux_paused unconditionally, which is scribbling in the giant
union which is overwriting state set by perf_init_event().
But I think there's more problems, we need to do the aux_action
validation after perf_get_aux_event(), we can't know if having those
bits set makes sense before that. This means the perf_event_alloc() site
is wrong in the first place.
I'm going to drop these patches for now. Please rework.
next prev parent reply other threads:[~2024-08-02 9:25 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20240801132638.GA8759@redhat.com>
[not found] ` <20240801133617.GA39708@noisy.programming.kicks-ass.net>
2024-08-01 18:58 ` [PATCH v4 0/9] uprobes: misc cleanups/simplifications Andrii Nakryiko
2024-08-01 21:13 ` Andrii Nakryiko
2024-08-02 8:27 ` Peter Zijlstra
2024-08-02 9:25 ` Peter Zijlstra [this message]
2024-08-02 11:02 ` Adrian Hunter
2024-08-02 17:14 ` Adrian Hunter
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