linux-kernel - [PATCH 2/9] perf tools: /proc/kcore requires CAP_SYS

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Fri, 21 Aug 2015 13:10:46 -0300
From:	Arnaldo Carvalho de Melo <acme@...nel.org>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	linux-kernel@...r.kernel.org,
	Adrian Hunter <adrian.hunter@...el.com>,
	Jiri Olsa <jolsa@...hat.com>,
	Li Zhang <zhlcindy@...ux.vnet.ibm.com>,
	Sukadev Bhattiprolu <sukadev@...ux.vnet.ibm.com>,
	Arnaldo Carvalho de Melo <acme@...hat.com>
Subject: [PATCH 2/9] perf tools: /proc/kcore requires CAP_SYS_RAWIO message too noisy

From: Adrian Hunter <adrian.hunter@...el.com>

The "/proc/kcore requires CAP_SYS_RAWIO" message comes up all the time
for 'perf script' if vmlinux is not found and the user isn't root, even
when the kernel is not being traced and even though the message is only
really relevant for annotation.

Change it to pr_debug and instead put a note in the message displayed if
annotation is not possible.

Also, the file being accessed might not be /proc/kcore.  Tools can be
directed to a different location using the --kallsyms option in which
case kcore is expected to be in the same directory.  Adjust the message
so it is not misleading in that case.

Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
Cc: Jiri Olsa <jolsa@...hat.com>
Cc: Li Zhang <zhlcindy@...ux.vnet.ibm.com>
Cc: Sukadev Bhattiprolu <sukadev@...ux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1440065260-8802-1-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
 tools/perf/util/annotate.c | 1 +
 tools/perf/util/symbol.c   | 4 ++--
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
index 8a18347709e1..d1eece70b84d 100644
--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -1126,6 +1126,7 @@ fallback:
 		dso->annotate_warned = 1;
 		pr_err("Can't annotate %s:\n\n"
 		       "No vmlinux file%s\nwas found in the path.\n\n"
+		       "Note that annotation using /proc/kcore requires CAP_SYS_RAWIO capability.\n\n"
 		       "Please use:\n\n"
 		       "  perf buildid-cache -vu vmlinux\n\n"
 		       "or:\n\n"
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 725640fd7cd8..42e98ab5a9bb 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -1138,8 +1138,8 @@ static int dso__load_kcore(struct dso *dso, struct map *map,
 
 	fd = open(kcore_filename, O_RDONLY);
 	if (fd < 0) {
-		pr_err("%s requires CAP_SYS_RAWIO capability to access.\n",
-			kcore_filename);
+		pr_debug("Failed to open %s. Note /proc/kcore requires CAP_SYS_RAWIO capability to access.\n",
+			 kcore_filename);
 		return -EINVAL;
 	}
 
-- 
2.1.0

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/