* [PATCH] perf parse-events: add defensive null check
@ 2020-03-25 16:40 Ian Rogers
2020-03-25 19:25 ` Arnaldo Carvalho de Melo
2020-04-04 8:41 ` [tip: perf/urgent] perf parse-events: Add defensive NULL check tip-bot2 for Ian Rogers
0 siblings, 2 replies; 4+ messages in thread
From: Ian Rogers @ 2020-03-25 16:40 UTC (permalink / raw)
To: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Mark Rutland, Alexander Shishkin, Jiri Olsa, Namhyung Kim,
John Garry, Jin Yao, Andi Kleen, Kan Liang, linux-kernel,
clang-built-linux
Cc: Stephane Eranian, Ian Rogers
Terms may have a null config in which case a strcmp will segv. This can
be reproduced with:
perf stat -e '*/event=?,nr/' sleep 1
Add a null check to avoid this. This was caught by LLVM's libfuzzer.
Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/perf/util/pmu.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 616fbda7c3fc..ef6a63f3d386 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -984,12 +984,11 @@ static int pmu_resolve_param_term(struct parse_events_term *term,
struct parse_events_term *t;
list_for_each_entry(t, head_terms, list) {
- if (t->type_val == PARSE_EVENTS__TERM_TYPE_NUM) {
- if (!strcmp(t->config, term->config)) {
- t->used = true;
- *value = t->val.num;
- return 0;
- }
+ if (t->type_val == PARSE_EVENTS__TERM_TYPE_NUM &&
+ t->config && !strcmp(t->config, term->config)) {
+ t->used = true;
+ *value = t->val.num;
+ return 0;
}
}
--
2.25.1.696.g5e7596f4ac-goog
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] perf parse-events: add defensive null check
2020-03-25 16:40 [PATCH] perf parse-events: add defensive null check Ian Rogers
@ 2020-03-25 19:25 ` Arnaldo Carvalho de Melo
2020-03-25 21:35 ` Ian Rogers
2020-04-04 8:41 ` [tip: perf/urgent] perf parse-events: Add defensive NULL check tip-bot2 for Ian Rogers
1 sibling, 1 reply; 4+ messages in thread
From: Arnaldo Carvalho de Melo @ 2020-03-25 19:25 UTC (permalink / raw)
To: Ian Rogers
Cc: Peter Zijlstra, Ingo Molnar, Mark Rutland, Alexander Shishkin,
Jiri Olsa, Namhyung Kim, John Garry, Jin Yao, Andi Kleen,
Kan Liang, linux-kernel, clang-built-linux, Stephane Eranian
Em Wed, Mar 25, 2020 at 09:40:22AM -0700, Ian Rogers escreveu:
> Terms may have a null config in which case a strcmp will segv. This can
> be reproduced with:
> perf stat -e '*/event=?,nr/' sleep 1
> Add a null check to avoid this. This was caught by LLVM's libfuzzer.
Adding the NULL check doesn't hurt, I guess, but I coudln't repro it:
[root@seventh ~]# perf stat -e '*/event=?,nr/' sleep 1
WARNING: multiple event parsing errors
event syntax error: '*/event=?,nr/'
\___ 'nr' is not usable in 'perf stat'
Initial error:
event syntax error: '*/event=?,nr/'
\___ Cannot find PMU `*'. Missing kernel support?
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
[root@seventh ~]#
Does this take place only when libfuzzer is being used?
- Arnaldo
> Signed-off-by: Ian Rogers <irogers@google.com>
> ---
> tools/perf/util/pmu.c | 11 +++++------
> 1 file changed, 5 insertions(+), 6 deletions(-)
>
> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
> index 616fbda7c3fc..ef6a63f3d386 100644
> --- a/tools/perf/util/pmu.c
> +++ b/tools/perf/util/pmu.c
> @@ -984,12 +984,11 @@ static int pmu_resolve_param_term(struct parse_events_term *term,
> struct parse_events_term *t;
>
> list_for_each_entry(t, head_terms, list) {
> - if (t->type_val == PARSE_EVENTS__TERM_TYPE_NUM) {
> - if (!strcmp(t->config, term->config)) {
> - t->used = true;
> - *value = t->val.num;
> - return 0;
> - }
> + if (t->type_val == PARSE_EVENTS__TERM_TYPE_NUM &&
> + t->config && !strcmp(t->config, term->config)) {
> + t->used = true;
> + *value = t->val.num;
> + return 0;
> }
> }
>
> --
> 2.25.1.696.g5e7596f4ac-goog
>
--
- Arnaldo
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] perf parse-events: add defensive null check
2020-03-25 19:25 ` Arnaldo Carvalho de Melo
@ 2020-03-25 21:35 ` Ian Rogers
0 siblings, 0 replies; 4+ messages in thread
From: Ian Rogers @ 2020-03-25 21:35 UTC (permalink / raw)
To: Arnaldo Carvalho de Melo
Cc: Peter Zijlstra, Ingo Molnar, Mark Rutland, Alexander Shishkin,
Jiri Olsa, Namhyung Kim, John Garry, Jin Yao, Andi Kleen,
Kan Liang, LKML, clang-built-linux, Stephane Eranian
On Wed, Mar 25, 2020 at 12:25 PM Arnaldo Carvalho de Melo
<arnaldo.melo@gmail.com> wrote:
>
> Em Wed, Mar 25, 2020 at 09:40:22AM -0700, Ian Rogers escreveu:
> > Terms may have a null config in which case a strcmp will segv. This can
> > be reproduced with:
> > perf stat -e '*/event=?,nr/' sleep 1
> > Add a null check to avoid this. This was caught by LLVM's libfuzzer.
>
> Adding the NULL check doesn't hurt, I guess, but I coudln't repro it:
>
> [root@seventh ~]# perf stat -e '*/event=?,nr/' sleep 1
> WARNING: multiple event parsing errors
> event syntax error: '*/event=?,nr/'
> \___ 'nr' is not usable in 'perf stat'
>
> Initial error:
> event syntax error: '*/event=?,nr/'
> \___ Cannot find PMU `*'. Missing kernel support?
> 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
> [root@seventh ~]#
>
> Does this take place only when libfuzzer is being used?
Good catch! I was driving the repro through the fuzzer and getting the
stack trace below and had assumed this would repro on the command
line. I'm now wondering why it won't reproduce :-) I suspect this
issue can come up in other scenarios so as you say the null check
won't hurt, but the commit message is incorrect.
#0 __interceptor_strcmp ()
at llvm/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc:448
#1 0x0000555557345eb2 in pmu_resolve_param_term (term=0x607000081190,
head_terms=0x602000007cb0,
value=0x7ffff4cc0320) at tools/perf/util/pmu.c:994
#2 0x00005555573389a4 in pmu_config_term (formats=0x6080000012c8,
attr=0x7ffff4dd4e20,
term=0x607000081190, head_terms=0x602000007cb0, zero=false,
err=0x7ffff4c90020)
at tools/perf/util/pmu.c:1117
#3 0x0000555557337b4e in perf_pmu__config_terms
(formats=0x6080000012c8, attr=0x7ffff4dd4e20,
head_terms=0x602000007cb0, zero=false, err=0x7ffff4c90020)
at tools/perf/util/pmu.c:1154
#4 0x0000555557338f7e in perf_pmu__config (pmu=0x6080000012a0,
attr=0x7ffff4dd4e20,
head_terms=0x602000007cb0, err=0x7ffff4c90020)
at tools/perf/util/pmu.c:1174
#5 0x0000555557314027 in parse_events_add_pmu
(parse_state=0x7ffff4c900a0, list=0x602000007e10,
name=0x602000001910 "uncore_cha_1", head_config=0x602000007cb0,
auto_merge_stats=true,
use_alias=false) at tools/perf/util/parse-events.c:1485
#6 0x0000555556d257f9 in parse_events_parse
(_parse_state=0x7ffff4c900a0, scanner=0x611000000cc0)
at tools/perf/util/parse-events.y:318
#7 0x000055555731c573 in parse_events__scanner (str=0x7ffff4d85c40
"*/event=?,nr/",
parse_state=0x7ffff4c900a0, start_token=258)
at tools/perf/util/parse-events.c:2026
#8 0x000055555731cbc3 in parse_events (evlist=0x61e000000080,
str=0x7ffff4d85c40 "*/event=?,nr/",
err=0x7ffff4c90020) at tools/perf/util/parse-events.c:2066
Thanks,
Ian
> - Arnaldo
>
> > Signed-off-by: Ian Rogers <irogers@google.com>
> > ---
> > tools/perf/util/pmu.c | 11 +++++------
> > 1 file changed, 5 insertions(+), 6 deletions(-)
> >
> > diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
> > index 616fbda7c3fc..ef6a63f3d386 100644
> > --- a/tools/perf/util/pmu.c
> > +++ b/tools/perf/util/pmu.c
> > @@ -984,12 +984,11 @@ static int pmu_resolve_param_term(struct parse_events_term *term,
> > struct parse_events_term *t;
> >
> > list_for_each_entry(t, head_terms, list) {
> > - if (t->type_val == PARSE_EVENTS__TERM_TYPE_NUM) {
> > - if (!strcmp(t->config, term->config)) {
> > - t->used = true;
> > - *value = t->val.num;
> > - return 0;
> > - }
> > + if (t->type_val == PARSE_EVENTS__TERM_TYPE_NUM &&
> > + t->config && !strcmp(t->config, term->config)) {
> > + t->used = true;
> > + *value = t->val.num;
> > + return 0;
> > }
> > }
> >
> > --
> > 2.25.1.696.g5e7596f4ac-goog
> >
>
> --
>
> - Arnaldo
^ permalink raw reply [flat|nested] 4+ messages in thread
* [tip: perf/urgent] perf parse-events: Add defensive NULL check
2020-03-25 16:40 [PATCH] perf parse-events: add defensive null check Ian Rogers
2020-03-25 19:25 ` Arnaldo Carvalho de Melo
@ 2020-04-04 8:41 ` tip-bot2 for Ian Rogers
1 sibling, 0 replies; 4+ messages in thread
From: tip-bot2 for Ian Rogers @ 2020-04-04 8:41 UTC (permalink / raw)
To: linux-tip-commits
Cc: Ian Rogers, Alexander Shishkin, Andi Kleen, Jin Yao, Jiri Olsa,
John Garry, Kan Liang, Mark Rutland, Namhyung Kim,
Peter Zijlstra, Stephane Eranian, clang-built-linux,
Arnaldo Carvalho de Melo, x86, LKML
The following commit has been merged into the perf/urgent branch of tip:
Commit-ID: 2a3d252dffe14582f238e21b09923e3772263123
Gitweb: https://git.kernel.org/tip/2a3d252dffe14582f238e21b09923e3772263123
Author: Ian Rogers <irogers@google.com>
AuthorDate: Wed, 25 Mar 2020 09:40:22 -07:00
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitterDate: Thu, 26 Mar 2020 11:03:53 -03:00
perf parse-events: Add defensive NULL check
Terms may have a NULL config in which case a strcmp will SEGV. This can
be reproduced with:
perf stat -e '*/event=?,nr/' sleep 1
Add a NULL check to avoid this. This was caught by LLVM's libfuzzer.
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: clang-built-linux@googlegroups.com
Link: http://lore.kernel.org/lkml/20200325164022.41385-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/pmu.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 616fbda..ef6a63f 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -984,12 +984,11 @@ static int pmu_resolve_param_term(struct parse_events_term *term,
struct parse_events_term *t;
list_for_each_entry(t, head_terms, list) {
- if (t->type_val == PARSE_EVENTS__TERM_TYPE_NUM) {
- if (!strcmp(t->config, term->config)) {
- t->used = true;
- *value = t->val.num;
- return 0;
- }
+ if (t->type_val == PARSE_EVENTS__TERM_TYPE_NUM &&
+ t->config && !strcmp(t->config, term->config)) {
+ t->used = true;
+ *value = t->val.num;
+ return 0;
}
}
^ permalink raw reply related [flat|nested] 4+ messages in thread
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2020-03-25 16:40 [PATCH] perf parse-events: add defensive null check Ian Rogers
2020-03-25 19:25 ` Arnaldo Carvalho de Melo
2020-03-25 21:35 ` Ian Rogers
2020-04-04 8:41 ` [tip: perf/urgent] perf parse-events: Add defensive NULL check tip-bot2 for Ian Rogers
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