* [PATCH v1] perf parse-events: Avoid segv if PMU lookup fails for legacy cache terms
@ 2023-07-12 6:52 Ian Rogers
2023-07-12 19:27 ` Arnaldo Carvalho de Melo
0 siblings, 1 reply; 3+ messages in thread
From: Ian Rogers @ 2023-07-12 6:52 UTC (permalink / raw)
To: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Mark Rutland, Alexander Shishkin, Jiri Olsa, Namhyung Kim,
Ian Rogers, Adrian Hunter, Kan Liang, Zhengjun Xing,
linux-perf-users, linux-kernel
libfuzzer found the following command could segv:
```
$ perf stat -e cpu/L2,L2/ true
```
This is because the L2 term rewrites the perf_event_attr type to
PERF_TYPE_HW_CACHE which then fails the PMU lookup for the second
legacy cache term.
The new failure is consistent with repeated hardware terms:
```
$ perf stat -e cpu/L2,L2/ true
event syntax error: 'cpu/L2,L2/'
\___ Failed to find PMU for type 3
Initial error:
event syntax error: 'cpu/L2,L2/'
\___ Failed to find PMU for type 3
Run 'perf list' for a list of valid events
Usage: perf stat [<options>] [<command>]
-e, --event <event> event selector. use 'perf list' to list available events
$ perf stat -e cpu/cycles,cycles/ true
event syntax error: 'cpu/cycles,cycles/'
\___ Failed to find PMU for type 0
Initial error:
event syntax error: 'cpu/cycles,cycles/'
\___ Failed to find PMU for type 0
Run 'perf list' for a list of valid events
Usage: perf stat [<options>] [<command>]
-e, --event <event> event selector. use 'perf list' to list available events
```
Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/perf/util/parse-events.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 5dcfbf316bf6..acde097e327c 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -1216,6 +1216,14 @@ static int config_term_pmu(struct perf_event_attr *attr,
if (term->type_term == PARSE_EVENTS__TERM_TYPE_LEGACY_CACHE) {
const struct perf_pmu *pmu = perf_pmus__find_by_type(attr->type);
+ if (!pmu) {
+ char *err_str;
+
+ if (asprintf(&err_str, "Failed to find PMU for type %d", attr->type) >= 0)
+ parse_events_error__handle(err, term->err_term,
+ err_str, /*help=*/NULL);
+ return -EINVAL;
+ }
if (perf_pmu__supports_legacy_cache(pmu)) {
attr->type = PERF_TYPE_HW_CACHE;
return parse_events__decode_legacy_cache(term->config, pmu->type,
--
2.41.0.390.g38632f3daf-goog
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v1] perf parse-events: Avoid segv if PMU lookup fails for legacy cache terms
2023-07-12 6:52 [PATCH v1] perf parse-events: Avoid segv if PMU lookup fails for legacy cache terms Ian Rogers
@ 2023-07-12 19:27 ` Arnaldo Carvalho de Melo
2023-07-12 20:29 ` Ian Rogers
0 siblings, 1 reply; 3+ messages in thread
From: Arnaldo Carvalho de Melo @ 2023-07-12 19:27 UTC (permalink / raw)
To: Ian Rogers
Cc: Peter Zijlstra, Ingo Molnar, Mark Rutland, Alexander Shishkin,
Jiri Olsa, Namhyung Kim, Adrian Hunter, Kan Liang, Zhengjun Xing,
linux-perf-users, linux-kernel
Em Tue, Jul 11, 2023 at 11:52:50PM -0700, Ian Rogers escreveu:
> libfuzzer found the following command could segv:
> ```
> $ perf stat -e cpu/L2,L2/ true
> ```
> This is because the L2 term rewrites the perf_event_attr type to
> PERF_TYPE_HW_CACHE which then fails the PMU lookup for the second
> legacy cache term.
>
> The new failure is consistent with repeated hardware terms:
> ```
> $ perf stat -e cpu/L2,L2/ true
> event syntax error: 'cpu/L2,L2/'
> \___ Failed to find PMU for type 3
>
> Initial error:
> event syntax error: 'cpu/L2,L2/'
> \___ Failed to find PMU for type 3
> Run 'perf list' for a list of valid events
>
> Usage: perf stat [<options>] [<command>]
>
> -e, --event <event> event selector. use 'perf list' to list available events
> $ perf stat -e cpu/cycles,cycles/ true
> event syntax error: 'cpu/cycles,cycles/'
> \___ Failed to find PMU for type 0
>
> Initial error:
> event syntax error: 'cpu/cycles,cycles/'
> \___ Failed to find PMU for type 0
> Run 'perf list' for a list of valid events
>
> Usage: perf stat [<options>] [<command>]
>
> -e, --event <event> event selector. use 'perf list' to list available events
> ```
I added the Fixes as requested:
Fixes: 6fd1e5191591f9d5 ("perf parse-events: Support PMUs for legacy cache events")
Please check if the patch below helps a bit giving more info to the
user, but still a bit cryptic:
⬢[acme@toolbox perf-tools]$ perf stat -e cpu/L2,L2/ true
event syntax error: 'cpu/L2,L2/'
\___ Failed to find PMU for perf_event_attr.type 3 (PERF_TYPE_HW_CACHE)
Initial error:
event syntax error: 'cpu/L2,L2/'
\___ Failed to find PMU for perf_event_attr.type 3 (PERF_TYPE_HW_CACHE)
Run 'perf list' for a list of valid events
Usage: perf stat [<options>] [<command>]
-e, --event <event> event selector. use 'perf list' to list available events
⬢[acme@toolbox perf-tools]$
And the other case is needs more patching, so better leave this for 6.6.
⬢[acme@toolbox perf-tools]$ perf stat -e cpu/cycles,cycles/ true
event syntax error: 'cpu/cycles,cycles/'
\___ Failed to find PMU for type 0
Initial error:
event syntax error: 'cpu/cycles,cycles/'
\___ Failed to find PMU for type 0
Run 'perf list' for a list of valid events
Usage: perf stat [<options>] [<command>]
-e, --event <event> event selector. use 'perf list' to list available events
⬢[acme@toolbox perf-tools]$
- Arnaldo
diff --git a/tools/perf/util/evsel_fprintf.h b/tools/perf/util/evsel_fprintf.h
index c8a9fac2f2ddc0f2..044612774a962020 100644
--- a/tools/perf/util/evsel_fprintf.h
+++ b/tools/perf/util/evsel_fprintf.h
@@ -4,6 +4,7 @@
#include <stdio.h>
#include <stdbool.h>
+#include <linux/types.h>
struct evsel;
@@ -45,6 +46,8 @@ int sample__fprintf_sym(struct perf_sample *sample, struct addr_location *al,
typedef int (*attr__fprintf_f)(FILE *, const char *, const char *, void *);
+const char *stringify_perf_type_id(u64 value);
+
int perf_event_attr__fprintf(FILE *fp, struct perf_event_attr *attr,
attr__fprintf_f attr__fprintf, void *priv);
#endif // __PERF_EVSEL_H
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index acde097e327cce8c..8678469cf974070a 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -25,6 +25,7 @@
#include "asm/bug.h"
#include "util/parse-branch-options.h"
#include "util/evsel_config.h"
+#include "util/evsel_fprintf.h"
#include "util/event.h"
#include "util/bpf-filter.h"
#include "util/util.h"
@@ -1219,9 +1220,11 @@ static int config_term_pmu(struct perf_event_attr *attr,
if (!pmu) {
char *err_str;
- if (asprintf(&err_str, "Failed to find PMU for type %d", attr->type) >= 0)
+ if (asprintf(&err_str, "Failed to find PMU for perf_event_attr.type %d (%s)", attr->type,
+ stringify_perf_type_id(attr->type)) >= 0) {
parse_events_error__handle(err, term->err_term,
err_str, /*help=*/NULL);
+ }
return -EINVAL;
}
if (perf_pmu__supports_legacy_cache(pmu)) {
diff --git a/tools/perf/util/perf_event_attr_fprintf.c b/tools/perf/util/perf_event_attr_fprintf.c
index 2247991451f3aa1b..ce97371eda027271 100644
--- a/tools/perf/util/perf_event_attr_fprintf.c
+++ b/tools/perf/util/perf_event_attr_fprintf.c
@@ -74,7 +74,7 @@ static void __p_read_format(char *buf, size_t size, u64 value)
}
#define ENUM_ID_TO_STR_CASE(x) case x: return (#x);
-static const char *stringify_perf_type_id(u64 value)
+const char *stringify_perf_type_id(u64 value)
{
switch (value) {
ENUM_ID_TO_STR_CASE(PERF_TYPE_HARDWARE)
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v1] perf parse-events: Avoid segv if PMU lookup fails for legacy cache terms
2023-07-12 19:27 ` Arnaldo Carvalho de Melo
@ 2023-07-12 20:29 ` Ian Rogers
0 siblings, 0 replies; 3+ messages in thread
From: Ian Rogers @ 2023-07-12 20:29 UTC (permalink / raw)
To: Arnaldo Carvalho de Melo
Cc: Peter Zijlstra, Ingo Molnar, Mark Rutland, Alexander Shishkin,
Jiri Olsa, Namhyung Kim, Adrian Hunter, Kan Liang, Zhengjun Xing,
linux-perf-users, linux-kernel
On Wed, Jul 12, 2023 at 12:27 PM Arnaldo Carvalho de Melo
<acme@kernel.org> wrote:
>
> Em Tue, Jul 11, 2023 at 11:52:50PM -0700, Ian Rogers escreveu:
> > libfuzzer found the following command could segv:
> > ```
> > $ perf stat -e cpu/L2,L2/ true
> > ```
> > This is because the L2 term rewrites the perf_event_attr type to
> > PERF_TYPE_HW_CACHE which then fails the PMU lookup for the second
> > legacy cache term.
> >
> > The new failure is consistent with repeated hardware terms:
> > ```
> > $ perf stat -e cpu/L2,L2/ true
> > event syntax error: 'cpu/L2,L2/'
> > \___ Failed to find PMU for type 3
> >
> > Initial error:
> > event syntax error: 'cpu/L2,L2/'
> > \___ Failed to find PMU for type 3
> > Run 'perf list' for a list of valid events
> >
> > Usage: perf stat [<options>] [<command>]
> >
> > -e, --event <event> event selector. use 'perf list' to list available events
> > $ perf stat -e cpu/cycles,cycles/ true
> > event syntax error: 'cpu/cycles,cycles/'
> > \___ Failed to find PMU for type 0
> >
> > Initial error:
> > event syntax error: 'cpu/cycles,cycles/'
> > \___ Failed to find PMU for type 0
> > Run 'perf list' for a list of valid events
> >
> > Usage: perf stat [<options>] [<command>]
> >
> > -e, --event <event> event selector. use 'perf list' to list available events
> > ```
>
> I added the Fixes as requested:
>
> Fixes: 6fd1e5191591f9d5 ("perf parse-events: Support PMUs for legacy cache events")
>
> Please check if the patch below helps a bit giving more info to the
> user, but still a bit cryptic:
>
> ⬢[acme@toolbox perf-tools]$ perf stat -e cpu/L2,L2/ true
> event syntax error: 'cpu/L2,L2/'
> \___ Failed to find PMU for perf_event_attr.type 3 (PERF_TYPE_HW_CACHE)
>
> Initial error:
> event syntax error: 'cpu/L2,L2/'
> \___ Failed to find PMU for perf_event_attr.type 3 (PERF_TYPE_HW_CACHE)
> Run 'perf list' for a list of valid events
>
> Usage: perf stat [<options>] [<command>]
>
> -e, --event <event> event selector. use 'perf list' to list available events
> ⬢[acme@toolbox perf-tools]$
>
> And the other case is needs more patching, so better leave this for 6.6.
>
>
> ⬢[acme@toolbox perf-tools]$ perf stat -e cpu/cycles,cycles/ true
> event syntax error: 'cpu/cycles,cycles/'
> \___ Failed to find PMU for type 0
>
> Initial error:
> event syntax error: 'cpu/cycles,cycles/'
> \___ Failed to find PMU for type 0
> Run 'perf list' for a list of valid events
>
> Usage: perf stat [<options>] [<command>]
>
> -e, --event <event> event selector. use 'perf list' to list available events
> ⬢[acme@toolbox perf-tools]$
The stringify looks good. Something strange is the value there is a
u64 by type is a __u32 in the perf_event_attr.
Thanks!
Ian
> - Arnaldo
>
> diff --git a/tools/perf/util/evsel_fprintf.h b/tools/perf/util/evsel_fprintf.h
> index c8a9fac2f2ddc0f2..044612774a962020 100644
> --- a/tools/perf/util/evsel_fprintf.h
> +++ b/tools/perf/util/evsel_fprintf.h
> @@ -4,6 +4,7 @@
>
> #include <stdio.h>
> #include <stdbool.h>
> +#include <linux/types.h>
>
> struct evsel;
>
> @@ -45,6 +46,8 @@ int sample__fprintf_sym(struct perf_sample *sample, struct addr_location *al,
>
> typedef int (*attr__fprintf_f)(FILE *, const char *, const char *, void *);
>
> +const char *stringify_perf_type_id(u64 value);
> +
> int perf_event_attr__fprintf(FILE *fp, struct perf_event_attr *attr,
> attr__fprintf_f attr__fprintf, void *priv);
> #endif // __PERF_EVSEL_H
> diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
> index acde097e327cce8c..8678469cf974070a 100644
> --- a/tools/perf/util/parse-events.c
> +++ b/tools/perf/util/parse-events.c
> @@ -25,6 +25,7 @@
> #include "asm/bug.h"
> #include "util/parse-branch-options.h"
> #include "util/evsel_config.h"
> +#include "util/evsel_fprintf.h"
> #include "util/event.h"
> #include "util/bpf-filter.h"
> #include "util/util.h"
> @@ -1219,9 +1220,11 @@ static int config_term_pmu(struct perf_event_attr *attr,
> if (!pmu) {
> char *err_str;
>
> - if (asprintf(&err_str, "Failed to find PMU for type %d", attr->type) >= 0)
> + if (asprintf(&err_str, "Failed to find PMU for perf_event_attr.type %d (%s)", attr->type,
> + stringify_perf_type_id(attr->type)) >= 0) {
> parse_events_error__handle(err, term->err_term,
> err_str, /*help=*/NULL);
> + }
> return -EINVAL;
> }
> if (perf_pmu__supports_legacy_cache(pmu)) {
> diff --git a/tools/perf/util/perf_event_attr_fprintf.c b/tools/perf/util/perf_event_attr_fprintf.c
> index 2247991451f3aa1b..ce97371eda027271 100644
> --- a/tools/perf/util/perf_event_attr_fprintf.c
> +++ b/tools/perf/util/perf_event_attr_fprintf.c
> @@ -74,7 +74,7 @@ static void __p_read_format(char *buf, size_t size, u64 value)
> }
>
> #define ENUM_ID_TO_STR_CASE(x) case x: return (#x);
> -static const char *stringify_perf_type_id(u64 value)
> +const char *stringify_perf_type_id(u64 value)
> {
> switch (value) {
> ENUM_ID_TO_STR_CASE(PERF_TYPE_HARDWARE)
^ permalink raw reply [flat|nested] 3+ messages in thread
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2023-07-12 6:52 [PATCH v1] perf parse-events: Avoid segv if PMU lookup fails for legacy cache terms Ian Rogers
2023-07-12 19:27 ` Arnaldo Carvalho de Melo
2023-07-12 20:29 ` Ian Rogers
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