From 7f0cd23615040b9e53bb4980c986b721cba08bbc Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Tue, 17 Oct 2017 22:29:00 +0900 Subject: [PATCH] perf buildid-list: Fix crash when processing PERF_RECORD_NAMESPACE Thomas reported that 'perf buildid-list' gets a SEGFAULT due to NULL pointer deref when he ran it on a data with namespace events. It was because the buildid_id__mark_dso_hit_ops lacks the namespace event handler and perf_too__fill_default() didn't set it. Program received signal SIGSEGV, Segmentation fault. 0x0000000000000000 in ?? () Missing separate debuginfos, use: dnf debuginfo-install audit-libs-2.7.7-1.fc25.s390x bzip2-libs-1.0.6-21.fc25.s390x elfutils-libelf-0.169-1.fc25.s390x +elfutils-libs-0.169-1.fc25.s390x libcap-ng-0.7.8-1.fc25.s390x numactl-libs-2.0.11-2.ibm.fc25.s390x openssl-libs-1.1.0e-1.1.ibm.fc25.s390x perl-libs-5.24.1-386.fc25.s390x +python-libs-2.7.13-2.fc25.s390x slang-2.3.0-7.fc25.s390x xz-libs-5.2.3-2.fc25.s390x zlib-1.2.8-10.fc25.s390x (gdb) where #0 0x0000000000000000 in ?? () #1 0x00000000010fad6a in machines__deliver_event (machines=, machines@entry=0x2c6fd18, evlist=, event=event@entry=0x3fffdf00470, sample=0x3ffffffe880, sample@entry=0x3ffffffe888, tool=tool@entry=0x1312968 , file_offset=1136) at util/session.c:1287 #2 0x00000000010fbf4e in perf_session__deliver_event (file_offset=1136, tool=0x1312968 , sample=0x3ffffffe888, event=0x3fffdf00470, session=0x2c6fc30) at util/session.c:1340 #3 perf_session__process_event (session=0x2c6fc30, session@entry=0x0, event=event@entry=0x3fffdf00470, file_offset=file_offset@entry=1136) at util/session.c:1522 #4 0x00000000010fddde in __perf_session__process_events (file_size=11880, data_size=, data_offset=, session=0x0) at util/session.c:1899 #5 perf_session__process_events (session=0x0, session@entry=0x2c6fc30) at util/session.c:1953 #6 0x000000000103b2ac in perf_session__list_build_ids (with_hits=, force=) at builtin-buildid-list.c:83 #7 cmd_buildid_list (argc=, argv=) at builtin-buildid-list.c:115 #8 0x00000000010a026c in run_builtin (p=0x1311f78 , argc=argc@entry=2, argv=argv@entry=0x3fffffff3c0) at perf.c:296 #9 0x000000000102bc00 in handle_internal_command (argv=, argc=2) at perf.c:348 #10 run_argv (argcp=, argv=) at perf.c:392 #11 main (argc=, argv=0x3fffffff3c0) at perf.c:536 (gdb) Fix it by adding a stub event handler for namespace event. Committer testing: Further clarifying, plain using 'perf buildid-list' will not end up in a SEGFAULT when processing a perf.data file with namespace info: # perf record -a --namespaces sleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 2.024 MB perf.data (1058 samples) ] # perf buildid-list | wc -l 38 # perf buildid-list | head -5 e2a171c7b905826fc8494f0711ba76ab6abbd604 /lib/modules/4.14.0-rc3+/build/vmlinux 874840a02d8f8a31cedd605d0b8653145472ced3 /lib/modules/4.14.0-rc3+/kernel/arch/x86/kvm/kvm-intel.ko ea7223776730cd8a22f320040aae4d54312984bc /lib/modules/4.14.0-rc3+/kernel/drivers/gpu/drm/i915/i915.ko 5961535e6732a8edb7f22b3f148bb2fa2e0be4b9 /lib/modules/4.14.0-rc3+/kernel/drivers/gpu/drm/drm.ko f045f54aa78cf1931cc893f78b6cbc52c72a8cb1 /usr/lib64/libc-2.25.so # It is only when one asks for checking what of those entries actually had samples, i.e. when we use either -H or --with-hits, that we will process all the PERF_RECORD_ events, and since tools/perf/builtin-buildid-list.c neither explicitely set a perf_tool.namespaces() callback nor the default stub was set that we end up, when processing a PERF_RECORD_NAMESPACE record, causing a SEGFAULT: # perf buildid-list -H Segmentation fault (core dumped) ^C # Reported-and-Tested-by: Thomas-Mich Richter Signed-off-by: Namhyung Kim Tested-by: Arnaldo Carvalho de Melo Cc: Hari Bathini Cc: Hendrik Brueckner Cc: Jiri Olsa Cc: Peter Zijlstra Cc: Thomas-Mich Richter Fixes: f3b3614a284d ("perf tools: Add PERF_RECORD_NAMESPACES to include namespaces related info") Link: http://lkml.kernel.org/r/20171017132900.11043-1-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/session.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c index a7ebd9fe8e40..76ab0709a20c 100644 --- a/tools/perf/util/session.c +++ b/tools/perf/util/session.c @@ -374,6 +374,8 @@ void perf_tool__fill_defaults(struct perf_tool *tool) tool->mmap2 = process_event_stub; if (tool->comm == NULL) tool->comm = process_event_stub; + if (tool->namespaces == NULL) + tool->namespaces = process_event_stub; if (tool->fork == NULL) tool->fork = process_event_stub; if (tool->exit == NULL)