Commit-ID: 1deec1bd96ccd8beb04d2112a6d12fe20505c3a6 Gitweb: http://git.kernel.org/tip/1deec1bd96ccd8beb04d2112a6d12fe20505c3a6 Author: Namhyung Kim <namhy...@kernel.org> AuthorDate: Wed, 31 May 2017 21:01:03 +0900 Committer: Arnaldo Carvalho de Melo <a...@redhat.com> CommitDate: Mon, 5 Jun 2017 14:16:49 -0300
perf header: Set proper module name when build-id event found When perf processes build-id event, it creates DSOs with the build-id. But it didn't set the module short name (like '[module-name]') so when processing a kernel mmap event of the module, it cannot found the DSO as it only checks the short names. That leads for perf to create a same DSO without the build-id info and it'll lookup the system path even if the DSO is already in the build-id cache. After kernel was updated, perf cannot find the DSO and cannot show symbols in it anymore. You can see this if you have an old data file (w/ old kernel version): $ perf report -i perf.data.old -v |& grep scsi_mod build id event received for /lib/modules/3.19.2-1-ARCH/kernel/drivers/scsi/scsi_mod.ko.gz : cafe1ce6ca13a98a5d9ed3425cde249e57a27fc1 Failed to open /lib/modules/3.19.2-1-ARCH/kernel/drivers/scsi/scsi_mod.ko.gz, continuing without symbols ... The second message didn't show the build-id. With this patch: $ perf report -i perf.data.old -v |& grep scsi_mod build id event received for /lib/modules/3.19.2-1-ARCH/kernel/drivers/scsi/scsi_mod.ko.gz: cafe1ce6ca13a98a5d9ed3425cde249e57a27fc1 /lib/modules/3.19.2-1-ARCH/kernel/drivers/scsi/scsi_mod.ko.gz with build id cafe1ce6ca13a98a5d9ed3425cde249e57a27fc1 not found, continuing without symbols ... Now it shows the build-id but still cannot load the symbol table. This is a different problem which will be fixed in the next patch. Signed-off-by: Namhyung Kim <namhy...@kernel.org> Acked-by: Jiri Olsa <jo...@kernel.org> Cc: Andi Kleen <a...@firstfloor.org> Cc: David Ahern <dsah...@gmail.com> Cc: Peter Zijlstra <a.p.zijls...@chello.nl> Cc: kernel-t...@lge.com Link: http://lkml.kernel.org/r/20170531120105.21731-1-namhy...@kernel.org [ Fix the build on older compilers (debian <= 8, fedora <= 21, etc) wrt kmod_path var init ] Signed-off-by: Arnaldo Carvalho de Melo <a...@redhat.com> --- tools/perf/util/header.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c index 314a071..c40a4d8 100644 --- a/tools/perf/util/header.c +++ b/tools/perf/util/header.c @@ -1469,8 +1469,16 @@ static int __event_process_build_id(struct build_id_event *bev, dso__set_build_id(dso, &bev->build_id); - if (!is_kernel_module(filename, cpumode)) - dso->kernel = dso_type; + if (dso_type != DSO_TYPE_USER) { + struct kmod_path m = { .name = NULL, }; + + if (!kmod_path__parse_name(&m, filename) && m.kmod) + dso__set_short_name(dso, strdup(m.name), true); + else + dso->kernel = dso_type; + + free(m.name); + } build_id__sprintf(dso->build_id, sizeof(dso->build_id), sbuild_id);
