ping ? On 2015年06月19日 16:57, Li Zhang wrote:
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 <[email protected]> --- v3 -> v2: * Add checking symbol files when user specify these files. * Report an error to users when open fails. Suggested by Sukar v2 -> v1: * Report one useful message to users about the access permision, then go back to the tools. Suggested by Arnaldo Carvalho de Melo. tools/perf/builtin-report.c | 11 +++++++++++ tools/perf/util/symbol.c | 5 ++++- 2 files changed, 15 insertions(+), 1 deletion(-) diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c index 476cdf7..1c353b1 100644 --- a/tools/perf/builtin-report.c +++ b/tools/perf/builtin-report.c @@ -731,6 +731,17 @@ 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 201f6c4c..46aa93d 100644 --- a/tools/perf/util/symbol.c +++ b/tools/perf/util/symbol.c @@ -1126,8 +1126,11 @@ 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,
-- Li Zhang IBM China Linux Technology Centre -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
