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authorLi Zhang <zhlcindy@linux.vnet.ibm.com>2015-06-19 16:57:33 +0800
committerArnaldo Carvalho de Melo <acme@redhat.com>2015-06-26 12:11:53 -0300
commit36c8bb56a9f718a9a5f35d1834ca9dcec95deb4a (patch)
treeca03e7f2fa83e2401af8f1c773c297baae2115b7 /tools
parent32b8af82e3708bc19af75c31fa773a98449f0edc (diff)
downloadop-kernel-dev-36c8bb56a9f718a9a5f35d1834ca9dcec95deb4a.zip
op-kernel-dev-36c8bb56a9f718a9a5f35d1834ca9dcec95deb4a.tar.gz
perf symbols: Check access permission when reading symbol files
There 2 problems when reading symbols files: * It doesn't report any errors even if when users specify symbol files which don't exist with --kallsyms or --vmlinux. The result just shows the address without symbols, which is not what is expected. So it's better to report errors and exit the program. * When using command perf report --kallsyms=/proc/kallsyms with a non-root user, symbols are resolved. Then select one symbol and annotate it, it reports the error as the following: Can't annotate __clear_user: No vmlinux file with build id xxx was found. The problem is caused by reading /proc/kcore without access permission. /proc/kcore requires CAP_SYS_RAWIO capability to access, so it needs to change access permission to allow a specific user to read /proc/kcore or use root to execute the perf command. This patch is to report errors when symbol files specified by users don't exist. And check access permission of /proc/kcore when reading it. Signed-off-by: Li Zhang <zhlcindy@linux.vnet.ibm.com> Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/1434704253-2632-1-git-send-email-zhlcindy@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools')
-rw-r--r--tools/perf/builtin-report.c11
-rw-r--r--tools/perf/util/symbol.c5
2 files changed, 15 insertions, 1 deletions
diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index 32626ea..348bed4 100644
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -742,6 +742,17 @@ int cmd_report(int argc, const char **argv, const char *prefix __maybe_unused)
argc = parse_options(argc, argv, options, report_usage, 0);
+ if (symbol_conf.vmlinux_name &&
+ access(symbol_conf.vmlinux_name, R_OK)) {
+ pr_err("Invalid file: %s\n", symbol_conf.vmlinux_name);
+ return -EINVAL;
+ }
+ if (symbol_conf.kallsyms_name &&
+ access(symbol_conf.kallsyms_name, R_OK)) {
+ pr_err("Invalid file: %s\n", symbol_conf.kallsyms_name);
+ return -EINVAL;
+ }
+
if (report.use_stdio)
use_browser = 0;
else if (report.use_tui)
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 504f2d7..48b588c 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -1132,8 +1132,11 @@ static int dso__load_kcore(struct dso *dso, struct map *map,
INIT_LIST_HEAD(&md.maps);
fd = open(kcore_filename, O_RDONLY);
- if (fd < 0)
+ if (fd < 0) {
+ pr_err("%s requires CAP_SYS_RAWIO capability to access.\n",
+ kcore_filename);
return -EINVAL;
+ }
/* Read new maps into temporary lists */
err = file__read_maps(fd, md.type == MAP__FUNCTION, kcore_mapfn, &md,
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