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Subject[tip:perf/urgent] perf header: Fix lock/unlock imbalances when processing BPF/BTF info
Commit-ID:  14c9b31a925a9f5c647523a12e2b575b97c0aa47
Gitweb: https://git.kernel.org/tip/14c9b31a925a9f5c647523a12e2b575b97c0aa47
Author: Gustavo A. R. Silva <gustavo@embeddedor.com>
AuthorDate: Mon, 8 Apr 2019 12:33:55 -0500
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Tue, 16 Apr 2019 11:26:43 -0300

perf header: Fix lock/unlock imbalances when processing BPF/BTF info

Fix lock/unlock imbalances by refactoring the code a bit and adding
calls to up_write() before return.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Acked-by: Song Liu <songliubraving@fb.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
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")
Link: http://lkml.kernel.org/r/20190408173355.GA10501@embeddedor
[ Simplified the exit path to have just one up_write() + return ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/header.c | 22 +++++++++++++---------
1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index b9e693825873..2d2af2ac2b1e 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 = NULL;
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 +2639,32 @@ 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;

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);
+ node = NULL;
}

+ err = 0;
+out:
up_write(&env->bpf_progs.lock);
- return 0;
+ free(node);
+ return err;
}

struct feature_ops {
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