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Message-Id: <20191104212141.041151631@linuxfoundation.org>
Date: Mon, 4 Nov 2019 22:44:14 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Ian Rogers <irogers@...gle.com>,
Arnaldo Carvalho de Melo <acme@...hat.com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Andi Kleen <ak@...ux.intel.com>, Jiri Olsa <jolsa@...hat.com>,
Namhyung Kim <namhyung@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
Stephane Eranian <eranian@...gle.com>,
Wang Nan <wangnan0@...wei.com>, Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.19 061/149] perf tests: Avoid raising SEGV using an obvious NULL dereference
From: Ian Rogers <irogers@...gle.com>
[ Upstream commit e3e2cf3d5b1fe800b032e14c0fdcd9a6fb20cf3b ]
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
Committer testing:
Before:
[root@...co ~]# perf test hooks
55: perf hooks : Ok
[root@...co ~]# perf test -v hooks
55: perf hooks :
--- start ---
test child forked, pid 17092
SIGSEGV is observed as expected, try to recover.
Fatal error (SEGFAULT) in perf hook 'test'
test child finished with 0
---- end ----
perf hooks: Ok
[root@...co ~]#
After:
[root@...co ~]# perf test hooks
55: perf hooks : Ok
[root@...co ~]# perf test -v hooks
55: perf hooks :
--- start ---
test child forked, pid 17909
SIGSEGV is observed as expected, try to recover.
Fatal error (SEGFAULT) in perf hook 'test'
test child finished with 0
---- end ----
perf hooks: Ok
[root@...co ~]#
Fixes: a074865e60ed ("perf tools: Introduce perf hooks")
Signed-off-by: Ian Rogers <irogers@...gle.com>
Tested-by: Arnaldo Carvalho de Melo <acme@...hat.com>
Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Cc: Andi Kleen <ak@...ux.intel.com>
Cc: Jiri Olsa <jolsa@...hat.com>
Cc: Namhyung Kim <namhyung@...nel.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Stephane Eranian <eranian@...gle.com>
Cc: Wang Nan <wangnan0@...wei.com>
Link: http://lore.kernel.org/lkml/20190925195924.152834-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
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 a693bcf017ea2..44c16fd11bf6e 100644
--- a/tools/perf/tests/perf-hooks.c
+++ b/tools/perf/tests/perf-hooks.c
@@ -20,12 +20,11 @@ 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)
--
2.20.1
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