From: peterz@infradead.org
To: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>,
Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org, Jiri Olsa <jolsa@kernel.org>,
alexey.budankov@linux.intel.com, adrian.hunter@intel.com,
Andi Kleen <ak@linux.intel.com>
Subject: Re: [PATCH 1/2] perf: Add closing sibling events' file descriptors
Date: Thu, 6 Aug 2020 10:35:30 +0200 [thread overview]
Message-ID: <20200806083530.GV2674@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20200708151635.81239-2-alexander.shishkin@linux.intel.com>
On Wed, Jul 08, 2020 at 06:16:34PM +0300, Alexander Shishkin wrote:
> Currently, perf requires one file descriptor per event. In large groups,
> this may mean running into the limit on open file descriptors. However,
> the sibling events in a group only need file descriptors for the initial
> configuration stage, after which they may not be needed any more.
>
> This adds an opt-in flag to the perf_event_open() syscall to retain
> sibling events after their file descriptors are closed. In this case, the
> actual events will be closed with the group leader.
So having the 1:1 relation with filedesc imposes a resource limit on
userspace.
This patch breaks that and enables a user to basically DoS the system by
creating unbound events.
next prev parent reply other threads:[~2020-08-06 11:05 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-08 15:16 [PATCH 0/2] perf: Allow closing siblings' file descriptors Alexander Shishkin
2020-07-08 15:16 ` [PATCH 1/2] perf: Add closing sibling events' " Alexander Shishkin
2020-08-06 8:35 ` peterz [this message]
2020-08-06 15:32 ` Andi Kleen
2020-08-10 13:57 ` Alexander Shishkin
2020-08-10 14:45 ` Andi Kleen
2020-08-10 20:36 ` Peter Zijlstra
2020-08-11 8:12 ` Alexey Budankov
2020-08-11 14:29 ` Andi Kleen
2020-08-11 14:47 ` David Laight
2020-08-11 18:03 ` Andi Kleen
2020-08-11 21:06 ` David Laight
2020-08-11 9:47 ` Alexander Shishkin
2020-08-11 14:34 ` Andi Kleen
2020-08-11 16:21 ` Alexander Shishkin
2020-08-11 18:02 ` Andi Kleen
2020-07-08 15:16 ` [PATCH 2/2] perf record: Support closing siblings' " Alexander Shishkin
2020-07-08 21:09 ` Jiri Olsa
2020-07-16 8:42 ` [perf record] d65f0cbbc6: perf-sanity-tests.Setup_struct_perf_event_attr.fail kernel test robot
2020-07-09 8:30 ` [PATCH 0/2] perf: Allow closing siblings' file descriptors Alexey Budankov
2020-08-06 6:15 ` Adrian Hunter
2020-08-06 8:37 ` peterz
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