From fbd733b815a5a57d7eb0d904edc49d18fd12df5c Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Fri, 20 Nov 2009 20:51:28 -0200 Subject: [PATCH] perf symbols: Check vmlinux buildid MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit E.g.: [root@doppio linux-2.6-tip]# perf top -v --vmlinux ../build/tip/vmlinux > /dev/null build_id in vmlinux is e96699725a47413a50c231864a8e7a8ced40a31b while expected is 18e7cc53db62a7d35e9d6f6c9ddc23017d38ee9a, ignoring it I.e. perf top was told to use a vmlinux file that is not the one currently running on the machine, it ignores it and falls back to using /proc/kallsyms. This solves many, at first, mysterious results when people have a stale vmlinux file while keeping the default of trying to use the vmlinux file in the current directory in things like 'perf annotate' where the DWARF info is required and thus we can't use just /proc/kallsyms. Modules buildids are already being checked as of the previous changeset in this series, because we are using the default dso__load routine, that will look at a series of places looking for the best file with a matching buildid, starting in the -debuginfo directories. Signed-off-by: Arnaldo Carvalho de Melo Cc: Frédéric Weisbecker Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Paul Mackerras LKML-Reference: <1258757489-5978-5-git-send-email-acme@infradead.org> Signed-off-by: Ingo Molnar --- tools/perf/util/symbol.c | 28 ++++++++++++++++++++++++++-- 1 file changed, 26 insertions(+), 2 deletions(-) diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c index cb086cb..9cf6dbc 100644 --- a/tools/perf/util/symbol.c +++ b/tools/perf/util/symbol.c @@ -1334,13 +1334,37 @@ out_failure: static int dso__load_vmlinux(struct dso *self, struct map *map, const char *vmlinux, symbol_filter_t filter) { - int err, fd = open(vmlinux, O_RDONLY); + int err = -1, fd; - self->loaded = 1; + if (self->has_build_id) { + u8 build_id[BUILD_ID_SIZE]; + + if (filename__read_build_id(vmlinux, build_id, + sizeof(build_id)) < 0) { + pr_debug("No build_id in %s, ignoring it\n", vmlinux); + return -1; + } + if (!dso__build_id_equal(self, build_id)) { + char expected_build_id[BUILD_ID_SIZE * 2 + 1], + vmlinux_build_id[BUILD_ID_SIZE * 2 + 1]; + + build_id__sprintf(self->build_id, + sizeof(self->build_id), + expected_build_id); + build_id__sprintf(build_id, sizeof(build_id), + vmlinux_build_id); + pr_debug("build_id in %s is %s while expected is %s, " + "ignoring it\n", vmlinux, vmlinux_build_id, + expected_build_id); + return -1; + } + } + fd = open(vmlinux, O_RDONLY); if (fd < 0) return -1; + self->loaded = 1; err = dso__load_sym(self, map, self->long_name, fd, filter, 1, 0); close(fd); -- 1.8.2.3