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| author | Li Zhang <zhlcindy@linux.vnet.ibm.com> | 2015-06-19 11:57:33 +0300 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2015-06-26 18:11:53 +0300 |
| commit | 36c8bb56a9f718a9a5f35d1834ca9dcec95deb4a (patch) | |
| tree | ca03e7f2fa83e2401af8f1c773c297baae2115b7 /tools/perf/util | |
| parent | 32b8af82e3708bc19af75c31fa773a98449f0edc (diff) | |
| download | linux-36c8bb56a9f718a9a5f35d1834ca9dcec95deb4a.tar.xz | |
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/perf/util')
| -rw-r--r-- | tools/perf/util/symbol.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c index 504f2d73b7ee..48b588c6951a 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, |