Re: [RFC][PATCH 2/3] perf: Fix u16 overflows

From: Ingo Molnar
Date: Sat Sep 12 2015 - 04:11:40 EST



* Peter Zijlstra <peterz@xxxxxxxxxxxxx> 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
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