6.16-stable review patch. If anyone has any objections, please let me know.
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From: Ian Rogers irogers@google.com
[ Upstream commit d7b67dd6f9db7bd2c49b415e901849b182ff0735 ]
Calls to perf_env__insert_bpf_prog_info may fail as a sideband thread may already have inserted the bpf_prog_info. Such failures may yield info_linear being freed which then causes use-after-free issues with the internal bpf_prog_info info struct. Make it so that perf_env__insert_bpf_prog_info trigger early non-error paths and fix the use-after-free in perf_event__synthesize_one_bpf_prog. Add proper return error handling to perf_env__add_bpf_info (that calls perf_env__insert_bpf_prog_info) and propagate the return value in its callers.
Closes: https://lore.kernel.org/lkml/CAP-5=fWJQcmUOP7MuCA2ihKnDAHUCOBLkQFEkQES-1ZZTr... Fixes: 03edb7020bb9 ("perf bpf: Fix two memory leakages when calling perf_env__insert_bpf_prog_info()") Reviewed-by: Namhyung Kim namhyung@kernel.org Signed-off-by: Ian Rogers irogers@google.com Link: https://lore.kernel.org/r/20250902181713.309797-2-irogers@google.com Signed-off-by: Namhyung Kim namhyung@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- tools/perf/util/bpf-event.c | 39 +++++++++++++++++++++++++------------ 1 file changed, 27 insertions(+), 12 deletions(-)
diff --git a/tools/perf/util/bpf-event.c b/tools/perf/util/bpf-event.c index c81444059ad07..d9123c9637baa 100644 --- a/tools/perf/util/bpf-event.c +++ b/tools/perf/util/bpf-event.c @@ -290,9 +290,15 @@ static int perf_event__synthesize_one_bpf_prog(struct perf_session *session,
info_node->info_linear = info_linear; if (!perf_env__insert_bpf_prog_info(env, info_node)) { - free(info_linear); + /* + * Insert failed, likely because of a duplicate event + * made by the sideband thread. Ignore synthesizing the + * metadata. + */ free(info_node); + goto out; } + /* info_linear is now owned by info_node and shouldn't be freed below. */ info_linear = NULL;
/* @@ -451,18 +457,18 @@ int perf_event__synthesize_bpf_events(struct perf_session *session, return err; }
-static void perf_env__add_bpf_info(struct perf_env *env, u32 id) +static int perf_env__add_bpf_info(struct perf_env *env, u32 id) { struct bpf_prog_info_node *info_node; struct perf_bpil *info_linear; struct btf *btf = NULL; u64 arrays; u32 btf_id; - int fd; + int fd, err = 0;
fd = bpf_prog_get_fd_by_id(id); if (fd < 0) - return; + return -EINVAL;
arrays = 1UL << PERF_BPIL_JITED_KSYMS; arrays |= 1UL << PERF_BPIL_JITED_FUNC_LENS; @@ -475,6 +481,7 @@ static void perf_env__add_bpf_info(struct perf_env *env, u32 id) info_linear = get_bpf_prog_info_linear(fd, arrays); if (IS_ERR_OR_NULL(info_linear)) { pr_debug("%s: failed to get BPF program info. aborting\n", __func__); + err = PTR_ERR(info_linear); goto out; }
@@ -484,38 +491,46 @@ static void perf_env__add_bpf_info(struct perf_env *env, u32 id) if (info_node) { info_node->info_linear = info_linear; if (!perf_env__insert_bpf_prog_info(env, info_node)) { + pr_debug("%s: duplicate add bpf info request for id %u\n", + __func__, btf_id); free(info_linear); free(info_node); + goto out; } - } else + } else { free(info_linear); + err = -ENOMEM; + goto out; + }
if (btf_id == 0) goto out;
btf = btf__load_from_kernel_by_id(btf_id); - if (libbpf_get_error(btf)) { - pr_debug("%s: failed to get BTF of id %u, aborting\n", - __func__, btf_id); - goto out; + if (!btf) { + err = -errno; + pr_debug("%s: failed to get BTF of id %u %d\n", __func__, btf_id, err); + } else { + perf_env__fetch_btf(env, btf_id, btf); } - perf_env__fetch_btf(env, btf_id, btf);
out: btf__free(btf); close(fd); + return err; }
static int bpf_event__sb_cb(union perf_event *event, void *data) { struct perf_env *env = data; + int ret = 0;
if (event->header.type != PERF_RECORD_BPF_EVENT) return -1;
switch (event->bpf.type) { case PERF_BPF_EVENT_PROG_LOAD: - perf_env__add_bpf_info(env, event->bpf.id); + ret = perf_env__add_bpf_info(env, event->bpf.id);
case PERF_BPF_EVENT_PROG_UNLOAD: /* @@ -529,7 +544,7 @@ static int bpf_event__sb_cb(union perf_event *event, void *data) break; }
- return 0; + return ret; }
int evlist__add_bpf_sb_event(struct evlist *evlist, struct perf_env *env)