Re: [PATCH] perf tools: Fix crash on buildid-list with namespace

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Em Tue, Oct 17, 2017 at 10:29:00PM +0900, Namhyung Kim escreveu:
> Thomas reported that perf buildid-list gets a segfault due to NULL
> pointer 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.

In these cases, next time I suggest you add a Fixes: tag, so that the
stable@kernel.org guys can automatically figure out which kernels need
this fix, in this case:

Fixes: f3b3614a284d ("perf tools: Add PERF_RECORD_NAMESPACES to include namespaces related info")

The script I have for this even adds this CC line:

Cc: Hari Bathini <hbathini@linux.vnet.ibm.com>

I'm adding it,

Thanks!

- Arnaldo
 
>   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=<optimized out>, machines@entry=0x2c6fd18,
>       evlist=<optimized out>, event=event@entry=0x3fffdf00470, sample=0x3ffffffe880, sample@entry=0x3ffffffe888,
>       tool=tool@entry=0x1312968 <build_id.mark_dso_hit_ops>, file_offset=1136) at util/session.c:1287
>   #2  0x00000000010fbf4e in perf_session__deliver_event (file_offset=1136, tool=0x1312968 <build_id.mark_dso_hit_ops>,
>       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=<optimized out>,
>       data_offset=<optimized out>, 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=<optimized out>, force=<optimized out>)
>       at builtin-buildid-list.c:83
>   #7  cmd_buildid_list (argc=<optimized out>, argv=<optimized out>) at builtin-buildid-list.c:115
>   #8  0x00000000010a026c in run_builtin (p=0x1311f78 <commands+24>, argc=argc@entry=2, argv=argv@entry=0x3fffffff3c0)
>       at perf.c:296
>   #9  0x000000000102bc00 in handle_internal_command (argv=<optimized out>, argc=2) at perf.c:348
>   #10 run_argv (argcp=<synthetic pointer>, argv=<synthetic pointer>) at perf.c:392
>   #11 main (argc=<optimized out>, argv=0x3fffffff3c0) at perf.c:536
>   (gdb)
> 
> Fix it by adding a stub event handler for namespace event.
> 
> Reported-and-Tested-by: Thomas-Mich Richter <tmricht@linux.vnet.ibm.com>
> Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> ---
>  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)
> -- 
> 2.14.2