From: Peter Zijlstra <peterz@infradead.org>
To: Song Liu <songliubraving@fb.com>
Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
acme@kernel.org, ast@kernel.org, daniel@iogearbox.net,
kernel-team@fb.com
Subject: Re: [PATCH v5 perf, bpf-next 3/7] perf, bpf: introduce PERF_RECORD_BPF_EVENT
Date: Tue, 8 Jan 2019 19:41:16 +0100 [thread overview]
Message-ID: <20190108184116.GC30894@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20181220182904.4193196-4-songliubraving@fb.com>
On Thu, Dec 20, 2018 at 10:29:00AM -0800, Song Liu wrote:
> @@ -986,9 +987,35 @@ enum perf_event_type {
> */
> PERF_RECORD_KSYMBOL = 17,
>
> + /*
> + * Record bpf events:
> + * enum perf_bpf_event_type {
> + * PERF_BPF_EVENT_UNKNOWN = 0,
> + * PERF_BPF_EVENT_PROG_LOAD = 1,
> + * PERF_BPF_EVENT_PROG_UNLOAD = 2,
> + * };
> + *
> + * struct {
> + * struct perf_event_header header;
> + * u16 type;
> + * u16 flags;
> + * u32 id;
> + * u8 tag[BPF_TAG_SIZE];
> + * struct sample_id sample_id;
> + * };
> + */
> + PERF_RECORD_BPF_EVENT = 18,
> +
Elsewhere today, I raised the point that by the time (however short
interval) userspace gets around to reading this event, the actual
program could be gone again.
In this case the program has been with us for a very short period
indeed; but it could still have generated some samples or otherwise
generated trace data.
It was suggested to allow pinning modules/programs to avoid this
situation, but that of course has other undesirable effects, such as a
trivial DoS.
A truly horrible hack would be to include an open filedesc in the event
that needs closing to release the resource, but I'm sorry for even
suggesting that **shudder**.
Do we have any sane ideas?
next prev parent reply other threads:[~2019-01-08 18:41 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-20 18:28 [PATCH v5 perf, bpf-next 0/7] reveal invisible bpf programs Song Liu
2018-12-20 18:28 ` [PATCH v5 perf, bpf-next 1/7] perf, bpf: Introduce PERF_RECORD_KSYMBOL Song Liu
2019-01-08 18:31 ` Peter Zijlstra
2019-01-08 18:56 ` Song Liu
2019-01-08 19:43 ` Peter Zijlstra
2018-12-20 18:28 ` [PATCH v5 perf, bpf-next 2/7] sync tools/include/uapi/linux/perf_event.h Song Liu
2018-12-20 18:29 ` [PATCH v5 perf, bpf-next 3/7] perf, bpf: introduce PERF_RECORD_BPF_EVENT Song Liu
2019-01-08 18:41 ` Peter Zijlstra [this message]
2019-01-08 19:10 ` Song Liu
2019-01-08 19:43 ` Peter Zijlstra
2019-01-08 23:54 ` Song Liu
2019-01-08 23:54 ` Song Liu
2019-01-09 10:18 ` Peter Zijlstra
2019-01-09 10:18 ` Peter Zijlstra
2019-01-09 11:32 ` Song Liu
2019-01-09 11:32 ` Song Liu
2019-01-09 12:59 ` Peter Zijlstra
2019-01-09 12:59 ` Peter Zijlstra
2019-01-09 16:04 ` Song Liu
2019-01-09 16:04 ` Song Liu
2019-01-08 20:16 ` Arnaldo Carvalho de Melo
2019-01-08 23:37 ` Song Liu
2019-01-08 23:37 ` Song Liu
2019-01-08 20:56 ` Alexei Starovoitov
2019-01-08 20:56 ` Alexei Starovoitov
2019-01-08 19:59 ` Peter Zijlstra
2019-01-08 20:29 ` Peter Zijlstra
2019-01-08 20:45 ` Alexei Starovoitov
2019-01-08 20:45 ` Alexei Starovoitov
2019-01-09 12:41 ` Peter Zijlstra
2019-01-09 12:41 ` Peter Zijlstra
2019-01-09 15:51 ` Song Liu
2019-01-09 15:51 ` Song Liu
2018-12-20 18:29 ` [PATCH v5 perf, bpf-next 4/7] sync tools/include/uapi/linux/perf_event.h Song Liu
2018-12-20 18:29 ` [PATCH v5 perf, bpf-next 5/7] perf util: handle PERF_RECORD_KSYMBOL Song Liu
2018-12-20 18:29 ` [PATCH v5 perf, bpf-next 6/7] perf util: handle PERF_RECORD_BPF_EVENT Song Liu
2018-12-20 18:29 ` [PATCH v5 perf, bpf-next 7/7] perf tools: synthesize PERF_RECORD_* for loaded BPF programs Song Liu
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