Re: [PATCH] perf: add sanity check on addr in symbol__inc_addr_samples()

[Stephane Eranian]

On Thu, Feb 9, 2012 at 3:48 PM, Arnaldo Carvalho de Melo
<acme@xxxxxxxxxx> wrote:
> Em Thu, Feb 09, 2012 at 11:30:16AM +0100, Stephane Eranian escreveu:
>>
>> Check the value of addr against the bounds of the symbol.
>> This is needed given we compute an offset:
>> Â Â Â offset = addr - sym->start
>>
>> And we don't want the offset to become negative.
>
> I'll try and add a debug option to show the backtrace and values of
> addr, sym, etc, so that we can fix the real problem.
>
> I.e. this function shouldn't be receiving any such invalid addresses, as
> the symbol lookup was done, the symbol was found to be this one, then
> why it would be out of bounds at this point?!
>
I tend to agree with you on this. But then I don't see why the first test
was there.

> - Arnaldo
>
>> Signed-off-by: Stephane Eranian <eranian@xxxxxxxxxx>
>>
>> diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
>> index 011ed26..8248d80 100644
>> --- a/tools/perf/util/annotate.c
>> +++ b/tools/perf/util/annotate.c
>> @@ -64,7 +64,7 @@ int symbol__inc_addr_samples(struct symbol *sym, struct map *map,
>>
>> Â Â Â pr_debug3("%s: addr=%#" PRIx64 "\n", __func__, map->unmap_ip(map, addr));
>>
>> - Â Â if (addr >= sym->end)
>> + Â Â if (addr >= sym->end || addr < sym->start)
>> Â Â Â Â Â Â Â return 0;
>>
>> Â Â Â offset = addr - sym->start;
--
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