From: Marco Elver <elver@google.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Ingo Molnar <mingo@redhat.com>, Jiri Olsa <jolsa@redhat.com>,
Mark Rutland <mark.rutland@arm.com>,
Namhyung Kim <namhyung@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Alexander Potapenko <glider@google.com>,
Al Viro <viro@zeniv.linux.org.uk>, Arnd Bergmann <arnd@arndb.de>,
Christian Brauner <christian@brauner.io>,
Dmitry Vyukov <dvyukov@google.com>, Jann Horn <jannh@google.com>,
Jens Axboe <axboe@kernel.dk>, Matt Morehouse <mascasa@google.com>,
Peter Collingbourne <pcc@google.com>,
Ian Rogers <irogers@google.com>,
kasan-dev <kasan-dev@googlegroups.com>,
linux-arch <linux-arch@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
"the arch/x86 maintainers" <x86@kernel.org>,
"open list:KERNEL SELFTEST FRAMEWORK"
<linux-kselftest@vger.kernel.org>
Subject: Re: [PATCH v3 07/11] perf: Add breakpoint information to siginfo on SIGTRAP
Date: Wed, 24 Mar 2021 15:05:01 +0100 [thread overview]
Message-ID: <CANpmjNPkBQwmNFO_hnUcjYGM=1SXJy+zgwb2dJeuOTAXphfDsw@mail.gmail.com> (raw)
In-Reply-To: <YFtF8tEPHrXnw7cX@hirez.programming.kicks-ass.net>
On Wed, 24 Mar 2021 at 15:01, Peter Zijlstra <peterz@infradead.org> wrote:
>
> One last try, I'll leave it alone now, I promise :-)
This looks like it does what you suggested, thanks! :-)
I'll still need to think about it, because of the potential problem
with modify-signal-races and what the user's synchronization story
would look like then.
> --- a/include/linux/perf_event.h
> +++ b/include/linux/perf_event.h
> @@ -778,6 +778,9 @@ struct perf_event {
> void *security;
> #endif
> struct list_head sb_list;
> +
> + unsigned long si_uattr;
> + unsigned long si_data;
> #endif /* CONFIG_PERF_EVENTS */
> };
>
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -5652,13 +5652,17 @@ static long _perf_ioctl(struct perf_even
> return perf_event_query_prog_array(event, (void __user *)arg);
>
> case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
> + struct perf_event_attr __user *uattr;
> struct perf_event_attr new_attr;
> - int err = perf_copy_attr((struct perf_event_attr __user *)arg,
> - &new_attr);
> + int err;
>
> + uattr = (struct perf_event_attr __user *)arg;
> + err = perf_copy_attr(uattr, &new_attr);
> if (err)
> return err;
>
> + event->si_uattr = (unsigned long)uattr;
> +
> return perf_event_modify_attr(event, &new_attr);
> }
> default:
> @@ -6399,7 +6403,12 @@ static void perf_sigtrap(struct perf_eve
> clear_siginfo(&info);
> info.si_signo = SIGTRAP;
> info.si_code = TRAP_PERF;
> - info.si_errno = event->attr.type;
> + info.si_addr = (void *)event->si_data;
> +
> + info.si_perf = event->si_uattr;
> + if (event->parent)
> + info.si_perf = event->parent->si_uattr;
> +
> force_sig_info(&info);
> }
>
> @@ -6414,8 +6423,8 @@ static void perf_pending_event_disable(s
> WRITE_ONCE(event->pending_disable, -1);
>
> if (event->attr.sigtrap) {
> - atomic_set(&event->event_limit, 1); /* rearm event */
> perf_sigtrap(event);
> + atomic_set_release(&event->event_limit, 1); /* rearm event */
> return;
> }
>
> @@ -9121,6 +9130,7 @@ static int __perf_event_overflow(struct
> if (events && atomic_dec_and_test(&event->event_limit)) {
> ret = 1;
> event->pending_kill = POLL_HUP;
> + event->si_data = data->addr;
>
> perf_event_disable_inatomic(event);
> }
> @@ -12011,6 +12021,8 @@ SYSCALL_DEFINE5(perf_event_open,
> goto err_task;
> }
>
> + event->si_uattr = (unsigned long)attr_uptr;
> +
> if (is_sampling_event(event)) {
> if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
> err = -EOPNOTSUPP;
next prev parent reply other threads:[~2021-03-24 14:05 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-24 11:24 [PATCH v3 00/11] Add support for synchronous signals on perf events Marco Elver
2021-03-24 11:24 ` [PATCH v3 01/11] perf: Rework perf_event_exit_event() Marco Elver
2021-03-25 10:17 ` Marco Elver
2021-03-25 16:17 ` Marco Elver
2021-03-25 19:10 ` Marco Elver
2021-03-29 11:50 ` Peter Zijlstra
2021-03-24 11:24 ` [PATCH v3 02/11] perf: Apply PERF_EVENT_IOC_MODIFY_ATTRIBUTES to children Marco Elver
2021-03-24 11:24 ` [PATCH v3 03/11] perf: Support only inheriting events if cloned with CLONE_THREAD Marco Elver
2021-03-24 11:24 ` [PATCH v3 04/11] perf: Add support for event removal on exec Marco Elver
2021-03-24 11:24 ` [PATCH v3 05/11] signal: Introduce TRAP_PERF si_code and si_perf to siginfo Marco Elver
2021-03-24 11:24 ` [PATCH v3 06/11] perf: Add support for SIGTRAP on perf events Marco Elver
2021-03-25 8:14 ` Marco Elver
2021-03-29 12:07 ` Peter Zijlstra
2021-03-29 14:27 ` Oleg Nesterov
2021-03-29 14:32 ` Marco Elver
2021-03-30 7:04 ` Peter Zijlstra
2021-03-29 18:22 ` Marco Elver
2021-03-29 18:33 ` Oleg Nesterov
2021-03-31 12:32 ` Marco Elver
2021-03-31 14:51 ` Peter Zijlstra
2021-03-31 16:50 ` Marco Elver
2021-03-24 11:24 ` [PATCH v3 07/11] perf: Add breakpoint information to siginfo on SIGTRAP Marco Elver
2021-03-24 12:53 ` Peter Zijlstra
2021-03-24 13:01 ` Peter Zijlstra
2021-03-24 13:21 ` Peter Zijlstra
2021-03-24 13:43 ` Peter Zijlstra
2021-03-24 14:00 ` Peter Zijlstra
2021-03-24 14:05 ` Marco Elver [this message]
2021-03-24 14:12 ` Dmitry Vyukov
2021-03-24 14:15 ` Dmitry Vyukov
2021-03-25 7:00 ` Marco Elver
2021-03-25 14:18 ` Ingo Molnar
2021-03-25 15:17 ` Marco Elver
2021-03-25 15:35 ` Ingo Molnar
2021-03-24 13:47 ` Marco Elver
2021-03-24 11:25 ` [PATCH v3 08/11] selftests/perf_events: Add kselftest for process-wide sigtrap handling Marco Elver
2021-03-24 11:25 ` [PATCH v3 09/11] selftests/perf_events: Add kselftest for remove_on_exec Marco Elver
2021-03-24 11:25 ` [PATCH v3 10/11] tools headers uapi: Sync tools/include/uapi/linux/perf_event.h Marco Elver
2021-03-24 11:25 ` [PATCH v3 11/11] perf test: Add basic stress test for sigtrap handling Marco Elver
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