From: Ian Rogers <irogers@google.com>
To: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
Andi Kleen <ak@linux.intel.com>,
linux-kernel@vger.kernel.org
Cc: Stephane Eranian <eranian@google.com>, Ian Rogers <irogers@google.com>
Subject: [PATCH 2/2] Avoid raising segv using an obvious null dereference
Date: Wed, 25 Sep 2019 12:59:24 -0700 [thread overview]
Message-ID: <20190925195924.152834-2-irogers@google.com> (raw)
In-Reply-To: <20190925195924.152834-1-irogers@google.com>
An optimized build such as:
make -C tools/perf CLANG=1 CC=clang EXTRA_CFLAGS="-O3
will turn the dereference operation into a ud2 instruction, raising a SIGILL
rather than a SIGSEGV. Use raise(..) for correctness and clarity.
Similar issues were addressed in Numfor Mbiziwo-Tiapo's patch:
https://lkml.org/lkml/2019/7/8/1234
Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/perf/tests/perf-hooks.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/tools/perf/tests/perf-hooks.c b/tools/perf/tests/perf-hooks.c
index dbc27199c65e..dd865e0bea12 100644
--- a/tools/perf/tests/perf-hooks.c
+++ b/tools/perf/tests/perf-hooks.c
@@ -19,12 +19,11 @@ static void sigsegv_handler(int sig __maybe_unused)
static void the_hook(void *_hook_flags)
{
int *hook_flags = _hook_flags;
- int *p = NULL;
*hook_flags = 1234;
/* Generate a segfault, test perf_hooks__recover */
- *p = 0;
+ raise(SIGSEGV);
}
int test__perf_hooks(struct test *test __maybe_unused, int subtest __maybe_unused)
--
2.23.0.351.gc4317032e6-goog
next prev parent reply other threads:[~2019-09-25 19:59 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-25 19:59 [PATCH 1/2] Make _FORTIFY_SOURCE defines dependent on the feature Ian Rogers
2019-09-25 19:59 ` Ian Rogers [this message]
2019-09-26 15:24 ` [PATCH 2/2] Avoid raising segv using an obvious null dereference Arnaldo Carvalho de Melo
2019-10-07 14:49 ` [tip: perf/urgent] perf tests: Avoid raising SEGV using an obvious NULL dereference tip-bot2 for Ian Rogers
2019-09-26 15:18 ` [PATCH 1/2] Make _FORTIFY_SOURCE defines dependent on the feature Arnaldo Carvalho de Melo
2019-10-07 14:49 ` [tip: perf/urgent] libsubcmd: " tip-bot2 for Ian Rogers
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