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From: Ingo Molnar <mingo@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, vincent.weaver@maine.edu,
	acme@kernel.org, eranian@google.com, jolsa@redhat.com,
	alexander.shishkin@linux.intel.com
Subject: Re: [RFC][PATCH 2/3] perf: Fix u16 overflows
Date: Sat, 12 Sep 2015 10:11:20 +0200	[thread overview]
Message-ID: <20150912081120.GB9737@gmail.com> (raw)
In-Reply-To: <20150910162007.946742153@infradead.org>


* Peter Zijlstra <peterz@infradead.org> wrote:

> Vince reported that its possible to overflow the various size fields
> and get weird stuff if you stick too many events in a group.
> 
> Put a lid on this by requiring the fixed record size not exceed 16k.
> This is still a fair amount of events (silly amount really) and leaves
> plenty room for callchains and stack dwarves while also avoiding
> overflowing the u16 variables.

Does this leave a natural ABI extension route here, in case in the future it 
becomes a problem? We should take aside a value to mean 'larger record' or such?

Could we list exactly which fields this concerns, in which structures?

Thanks,

	Ingo

  reply	other threads:[~2015-09-12  8:11 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-09-10 16:16 [RFC][PATCH 0/3] variuos perf fixes Peter Zijlstra
2015-09-10 16:16 ` [RFC][PATCH 1/3] perf: Restructure perf syscall point of no return Peter Zijlstra
2015-09-10 16:16 ` [RFC][PATCH 2/3] perf: Fix u16 overflows Peter Zijlstra
2015-09-12  8:11   ` Ingo Molnar [this message]
2015-09-14  9:06     ` Peter Zijlstra
2015-09-14  9:31       ` Ingo Molnar
2015-09-10 16:16 ` [RFC][PATCH 3/3] perf: Fix races in computing the header sizes Peter Zijlstra
2015-09-13 23:10 ` [RFC][PATCH 0/3] variuos perf fixes Vince Weaver
2015-09-14  6:57   ` Peter Zijlstra

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