* [PATCH v4] perf tools: perf_event_paranoid and kptr_restrict may crash on 'perf top'
@ 2021-03-16 1:24 Jackie Liu
2021-03-16 13:00 ` Jiri Olsa
2021-03-16 13:15 ` Arnaldo Carvalho de Melo
0 siblings, 2 replies; 3+ messages in thread
From: Jackie Liu @ 2021-03-16 1:24 UTC (permalink / raw)
To: jolsa, linux-kernel
Cc: Jackie Liu, Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Mark Rutland, Alexander Shishkin, Namhyung Kim
After install the libelf-dev package and compiling perf, kptr_restrict=2
and perf_event_paranoid=3 will cause perf top to crash, because the
value of /proc/kallsyms cannot be obtained, which leads to
info->jited_ksyms == NULL. In order to solve this problem, Add a
judgment before use.
v3->v4:
Fix memory leaks in more places
v2->v3:
free info_linear memory and move code above, don't do those extra btf
checks.
Suggested-by: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Jackie Liu <liuyun01@kylinos.cn>
---
tools/perf/util/bpf-event.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/tools/perf/util/bpf-event.c b/tools/perf/util/bpf-event.c
index 57d58c81a5f8..cdecda1ddd36 100644
--- a/tools/perf/util/bpf-event.c
+++ b/tools/perf/util/bpf-event.c
@@ -196,25 +196,32 @@ static int perf_event__synthesize_one_bpf_prog(struct perf_session *session,
}
if (info_linear->info_len < offsetof(struct bpf_prog_info, prog_tags)) {
+ free(info_linear);
pr_debug("%s: the kernel is too old, aborting\n", __func__);
return -2;
}
info = &info_linear->info;
+ if (!info->jited_ksyms) {
+ free(info_linear);
+ return -1;
+ }
/* number of ksyms, func_lengths, and tags should match */
sub_prog_cnt = info->nr_jited_ksyms;
if (sub_prog_cnt != info->nr_prog_tags ||
- sub_prog_cnt != info->nr_jited_func_lens)
+ sub_prog_cnt != info->nr_jited_func_lens) {
+ free(info_linear);
return -1;
+ }
/* check BTF func info support */
if (info->btf_id && info->nr_func_info && info->func_info_rec_size) {
/* btf func info number should be same as sub_prog_cnt */
if (sub_prog_cnt != info->nr_func_info) {
pr_debug("%s: mismatch in BPF sub program count and BTF function info count, aborting\n", __func__);
- err = -1;
- goto out;
+ free(info_linear);
+ return -1;
}
if (btf__get_from_id(info->btf_id, &btf)) {
pr_debug("%s: failed to get BTF of id %u, aborting\n", __func__, info->btf_id);
--
2.25.1
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH v4] perf tools: perf_event_paranoid and kptr_restrict may crash on 'perf top'
2021-03-16 1:24 [PATCH v4] perf tools: perf_event_paranoid and kptr_restrict may crash on 'perf top' Jackie Liu
@ 2021-03-16 13:00 ` Jiri Olsa
2021-03-16 13:15 ` Arnaldo Carvalho de Melo
1 sibling, 0 replies; 3+ messages in thread
From: Jiri Olsa @ 2021-03-16 13:00 UTC (permalink / raw)
To: Jackie Liu
Cc: linux-kernel, Jackie Liu, Peter Zijlstra, Ingo Molnar,
Arnaldo Carvalho de Melo, Mark Rutland, Alexander Shishkin,
Namhyung Kim
On Tue, Mar 16, 2021 at 09:24:53AM +0800, Jackie Liu wrote:
> After install the libelf-dev package and compiling perf, kptr_restrict=2
> and perf_event_paranoid=3 will cause perf top to crash, because the
> value of /proc/kallsyms cannot be obtained, which leads to
> info->jited_ksyms == NULL. In order to solve this problem, Add a
> judgment before use.
>
> v3->v4:
> Fix memory leaks in more places
Acked-by: Jiri Olsa <jolsa@redhat.com>
thanks,
jirka
>
> v2->v3:
> free info_linear memory and move code above, don't do those extra btf
> checks.
>
> Suggested-by: Jiri Olsa <jolsa@redhat.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Signed-off-by: Jackie Liu <liuyun01@kylinos.cn>
> ---
> tools/perf/util/bpf-event.c | 13 ++++++++++---
> 1 file changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/tools/perf/util/bpf-event.c b/tools/perf/util/bpf-event.c
> index 57d58c81a5f8..cdecda1ddd36 100644
> --- a/tools/perf/util/bpf-event.c
> +++ b/tools/perf/util/bpf-event.c
> @@ -196,25 +196,32 @@ static int perf_event__synthesize_one_bpf_prog(struct perf_session *session,
> }
>
> if (info_linear->info_len < offsetof(struct bpf_prog_info, prog_tags)) {
> + free(info_linear);
> pr_debug("%s: the kernel is too old, aborting\n", __func__);
> return -2;
> }
>
> info = &info_linear->info;
> + if (!info->jited_ksyms) {
> + free(info_linear);
> + return -1;
> + }
>
> /* number of ksyms, func_lengths, and tags should match */
> sub_prog_cnt = info->nr_jited_ksyms;
> if (sub_prog_cnt != info->nr_prog_tags ||
> - sub_prog_cnt != info->nr_jited_func_lens)
> + sub_prog_cnt != info->nr_jited_func_lens) {
> + free(info_linear);
> return -1;
> + }
>
> /* check BTF func info support */
> if (info->btf_id && info->nr_func_info && info->func_info_rec_size) {
> /* btf func info number should be same as sub_prog_cnt */
> if (sub_prog_cnt != info->nr_func_info) {
> pr_debug("%s: mismatch in BPF sub program count and BTF function info count, aborting\n", __func__);
> - err = -1;
> - goto out;
> + free(info_linear);
> + return -1;
> }
> if (btf__get_from_id(info->btf_id, &btf)) {
> pr_debug("%s: failed to get BTF of id %u, aborting\n", __func__, info->btf_id);
> --
> 2.25.1
>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH v4] perf tools: perf_event_paranoid and kptr_restrict may crash on 'perf top'
2021-03-16 1:24 [PATCH v4] perf tools: perf_event_paranoid and kptr_restrict may crash on 'perf top' Jackie Liu
2021-03-16 13:00 ` Jiri Olsa
@ 2021-03-16 13:15 ` Arnaldo Carvalho de Melo
1 sibling, 0 replies; 3+ messages in thread
From: Arnaldo Carvalho de Melo @ 2021-03-16 13:15 UTC (permalink / raw)
To: Jackie Liu
Cc: jolsa, linux-kernel, Jackie Liu, Peter Zijlstra, Ingo Molnar,
Mark Rutland, Alexander Shishkin, Namhyung Kim
Em Tue, Mar 16, 2021 at 09:24:53AM +0800, Jackie Liu escreveu:
> After install the libelf-dev package and compiling perf, kptr_restrict=2
> and perf_event_paranoid=3 will cause perf top to crash, because the
> value of /proc/kallsyms cannot be obtained, which leads to
> info->jited_ksyms == NULL. In order to solve this problem, Add a
> judgment before use.
>
> v3->v4:
> Fix memory leaks in more places
>
> v2->v3:
> free info_linear memory and move code above, don't do those extra btf
> checks.
Applied, edited the commit message to:
----
perf top: Fix BPF support related crash with perf_event_paranoid=3 + kptr_restrict
After installing the libelf-dev package and compiling perf, if we have
kptr_restrict=2 and perf_event_paranoid=3 'perf top' will crash because
the value of /proc/kallsyms cannot be obtained, which leads to
info->jited_ksyms == NULL. In order to solve this problem, Add a
check before use.
Also plug some leaks on the error path.
----
> Suggested-by: Jiri Olsa <jolsa@redhat.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Signed-off-by: Jackie Liu <liuyun01@kylinos.cn>
> ---
> tools/perf/util/bpf-event.c | 13 ++++++++++---
> 1 file changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/tools/perf/util/bpf-event.c b/tools/perf/util/bpf-event.c
> index 57d58c81a5f8..cdecda1ddd36 100644
> --- a/tools/perf/util/bpf-event.c
> +++ b/tools/perf/util/bpf-event.c
> @@ -196,25 +196,32 @@ static int perf_event__synthesize_one_bpf_prog(struct perf_session *session,
> }
>
> if (info_linear->info_len < offsetof(struct bpf_prog_info, prog_tags)) {
> + free(info_linear);
> pr_debug("%s: the kernel is too old, aborting\n", __func__);
> return -2;
> }
>
> info = &info_linear->info;
> + if (!info->jited_ksyms) {
> + free(info_linear);
> + return -1;
> + }
>
> /* number of ksyms, func_lengths, and tags should match */
> sub_prog_cnt = info->nr_jited_ksyms;
> if (sub_prog_cnt != info->nr_prog_tags ||
> - sub_prog_cnt != info->nr_jited_func_lens)
> + sub_prog_cnt != info->nr_jited_func_lens) {
> + free(info_linear);
> return -1;
> + }
>
> /* check BTF func info support */
> if (info->btf_id && info->nr_func_info && info->func_info_rec_size) {
> /* btf func info number should be same as sub_prog_cnt */
> if (sub_prog_cnt != info->nr_func_info) {
> pr_debug("%s: mismatch in BPF sub program count and BTF function info count, aborting\n", __func__);
> - err = -1;
> - goto out;
> + free(info_linear);
> + return -1;
> }
> if (btf__get_from_id(info->btf_id, &btf)) {
> pr_debug("%s: failed to get BTF of id %u, aborting\n", __func__, info->btf_id);
> --
> 2.25.1
>
--
- Arnaldo
^ permalink raw reply [flat|nested] 3+ messages in thread
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2021-03-16 1:24 [PATCH v4] perf tools: perf_event_paranoid and kptr_restrict may crash on 'perf top' Jackie Liu
2021-03-16 13:00 ` Jiri Olsa
2021-03-16 13:15 ` Arnaldo Carvalho de Melo
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