linux-kernel - Re: [PATCH] perf header: Fix lock/unlock imbalances

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Message-ID: <3867ffda-5d01-412b-ed55-e39ee9db2ceb@embeddedor.com>
Date:   Mon, 8 Apr 2019 13:26:09 -0500
From:   "Gustavo A. R. Silva" <gustavo@...eddedor.com>
To:     Song Liu <songliubraving@...com>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] perf header: Fix lock/unlock imbalances



On 4/8/19 1:22 PM, Song Liu wrote:
> 
> 
>> On Apr 8, 2019, at 10:33 AM, Gustavo A. R. Silva <gustavo@...eddedor.com> wrote:
>>
>> Fix lock/unlock imbalances by refactoring the code a bit and adding
>> calls to up_write() before return.
>>
>> Addresses-Coverity-ID: 1444315 ("Missing unlock")
>> Addresses-Coverity-ID: 1444316 ("Missing unlock")
>> Fixes: a70a1123174a ("perf bpf: Save BTF information as headers to perf.data")
>> Fixes: 606f972b1361 ("perf bpf: Save bpf_prog_info information as headers to perf.data")
>> Signed-off-by: Gustavo A. R. Silva <gustavo@...eddedor.com>
> 
> Acked-by: Song Liu <songliubraving@...com>
> 
> Thanks for the fix!
> 

Glad to help. :)

Thanks
--
Gustavo

>> ---
>> tools/perf/util/header.c | 21 +++++++++++++--------
>> 1 file changed, 13 insertions(+), 8 deletions(-)
>>
>> diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
>> index b9e693825873..06028e0ee06a 100644
>> --- a/tools/perf/util/header.c
>> +++ b/tools/perf/util/header.c
>> @@ -2606,6 +2606,7 @@ static int process_bpf_prog_info(struct feat_fd *ff, void *data __maybe_unused)
>> 		perf_env__insert_bpf_prog_info(env, info_node);
>> 	}
>>
>> +	up_write(&env->bpf_progs.lock);
>> 	return 0;
>> out:
>> 	free(info_linear);
>> @@ -2623,7 +2624,9 @@ static int process_bpf_prog_info(struct feat_fd *ff __maybe_unused, void *data _
>> static int process_bpf_btf(struct feat_fd *ff, void *data __maybe_unused)
>> {
>> 	struct perf_env *env = &ff->ph->env;
>> +	struct btf_node *node;
>> 	u32 count, i;
>> +	int err = -1;
>>
>> 	if (ff->ph->needs_swap) {
>> 		pr_warning("interpreting btf from systems with endianity is not yet supported\n");
>> @@ -2636,31 +2639,33 @@ static int process_bpf_btf(struct feat_fd *ff, void *data __maybe_unused)
>> 	down_write(&env->bpf_progs.lock);
>>
>> 	for (i = 0; i < count; ++i) {
>> -		struct btf_node *node;
>> 		u32 id, data_size;
>>
>> +		node = NULL;
>> 		if (do_read_u32(ff, &id))
>> -			return -1;
>> +			goto out;
>> 		if (do_read_u32(ff, &data_size))
>> -			return -1;
>> +			goto out;
>>
>> 		node = malloc(sizeof(struct btf_node) + data_size);
>> 		if (!node)
>> -			return -1;
>> +			goto out;
>>
>> 		node->id = id;
>> 		node->data_size = data_size;
>>
>> -		if (__do_read(ff, node->data, data_size)) {
>> -			free(node);
>> -			return -1;
>> -		}
>> +		if (__do_read(ff, node->data, data_size))
>> +			goto out;
>>
>> 		perf_env__insert_btf(env, node);
>> 	}
>>
>> 	up_write(&env->bpf_progs.lock);
>> 	return 0;
>> +out:
>> +	up_write(&env->bpf_progs.lock);
>> +	free(node);
>> +	return err;
>> }
>>
>> struct feature_ops {
>> -- 
>> 2.21.0
>>
>