This is a note to let you know that I've just added the patch titled
perf env: Do not return pointers to local variables
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
perf-env-do-not-return-pointers-to-local-variables.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ebcb9464a2ae3a547e97de476575c82ece0e93e2 Mon Sep 17 00:00:00 2001
From: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Date: Mon, 2 Mar 2020 11:23:03 -0300
Subject: perf env: Do not return pointers to local variables
From: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
commit ebcb9464a2ae3a547e97de476575c82ece0e93e2 upstream.
It is possible to return a pointer to a local variable when looking up
the architecture name for the running system and no normalization is
done on that value, i.e. we may end up returning the uts.machine local
variable.
While this doesn't happen on most arches, as normalization takes place,
lets fix this by making that a static variable and optimize it a bit by
not always running uname(), only the first time.
Noticed in fedora rawhide running with:
[perfbuilder@a5ff49d6e6e4 ~]$ gcc --version
gcc (GCC) 10.0.1 20200216 (Red Hat 10.0.1-0.8)
Reported-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
tools/perf/util/env.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/tools/perf/util/env.c
+++ b/tools/perf/util/env.c
@@ -163,11 +163,11 @@ static const char *normalize_arch(char *
const char *perf_env__arch(struct perf_env *env)
{
- struct utsname uts;
char *arch_name;
if (!env || !env->arch) { /* Assume local operation */
- if (uname(&uts) < 0)
+ static struct utsname uts = { .machine[0] = '\0', };
+ if (uts.machine[0] == '\0' && uname(&uts) < 0)
return NULL;
arch_name = uts.machine;
} else
Patches currently in stable-queue which might be from acme@xxxxxxxxxx are
queue-4.19/perf-env-do-not-return-pointers-to-local-variables.patch
