Re: [PATCH 1/1] perf map: Fix error return code in maps__clone()

[Leizhen (ThunderTown)]

On 2021/4/15 20:42, Arnaldo Carvalho de Melo wrote:
> Em Thu, Apr 15, 2021 at 05:27:44PM +0800, Zhen Lei escreveu:
>> Although 'err' has been initialized to -ENOMEM, but it will be reassigned
>> by the "err = unwind__prepare_access(...)" statement in the for loop. So
>> that, the value of 'err' is unknown when map__clone() failed.
> 
> You forgot to research and add this:
> 
> Fixes: 6c502584438bda63 ("perf unwind: Call unwind__prepare_access for forked thread")
> 
> So that the stable@xxxxxxxxxx guys can pick this up automagically and
> apply this fix to the stable kernels.
> 
> I've added it.

OK, thank you very much.

> 
> Thanks, applied.
> 
> - Arnaldo
>  
>> Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
>> Signed-off-by: Zhen Lei <thunder.leizhen@xxxxxxxxxx>
>> ---
>>  tools/perf/util/map.c | 7 +++++--
>>  1 file changed, 5 insertions(+), 2 deletions(-)
>>
>> diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
>> index fbc40a2c17d4dca..8af693d9678cefe 100644
>> --- a/tools/perf/util/map.c
>> +++ b/tools/perf/util/map.c
>> @@ -840,15 +840,18 @@ int maps__fixup_overlappings(struct maps *maps, struct map *map, FILE *fp)
>>  int maps__clone(struct thread *thread, struct maps *parent)
>>  {
>>  	struct maps *maps = thread->maps;
>> -	int err = -ENOMEM;
>> +	int err;
>>  	struct map *map;
>>  
>>  	down_read(&parent->lock);
>>  
>>  	maps__for_each_entry(parent, map) {
>>  		struct map *new = map__clone(map);
>> -		if (new == NULL)
>> +
>> +		if (new == NULL) {
>> +			err = -ENOMEM;
>>  			goto out_unlock;
>> +		}
>>  
>>  		err = unwind__prepare_access(maps, new, NULL);
>>  		if (err)
>> -- 
>> 2.26.0.106.g9fadedd
>>
>>
>