Re: [PATCH 16/35] perf annotate: Add samples into struct annotation_line

[Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>]

Hi Jiri,

This patch seems to be causing segfault with "perf top --stdio".

Steps to reproduce:
1. start "perf top --stdio" in one terminal
2. run some simple workload in another terminal, let it get finished.
3. annotate function from previous workload in perf top (press 'a' 
followed by 's')

Perf will crash with:

   perf: Segmentation fault
   Obtained 8 stack frames.
   ./perf(sighandler_dump_stack+0x3e) [0x4f1b6e]
   /lib64/libc.so.6(+0x36a7f) [0x7ff3aa7e4a7f]
   ./perf() [0x4a27fd]
   ./perf(symbol__annotate+0x199) [0x4a4439]
   ./perf() [0x44e32d]
   ./perf() [0x44f098]
   /lib64/libpthread.so.0(+0x736c) [0x7ff3acee836c]
   /lib64/libc.so.6(clone+0x3e) [0x7ff3aa8bee1e]

Can you please check.

Thanks,
Ravi


On 10/11/2017 08:31 PM, Jiri Olsa wrote:
> Adding samples array into struct annotation_line to
> hold the annotation data. The data are populated in
> the following patches.
>
> Link: http://lkml.kernel.org/n/tip-97yja5m7z9brrcuf2gwr56t2@git.kernel.org
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
>   tools/perf/util/annotate.c |  8 ++++++++
>   tools/perf/util/annotate.h | 17 ++++++++++++-----
>   2 files changed, 20 insertions(+), 5 deletions(-)
>
> diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
> index 8e1e88aab45a..1b5c7d0a53e8 100644
> --- a/tools/perf/util/annotate.c
> +++ b/tools/perf/util/annotate.c
> @@ -901,7 +901,14 @@ static struct annotation_line*
>   annotation_line__new(struct annotate_args *args, size_t privsize)
>   {
>   	struct annotation_line *al;
> +	struct perf_evsel *evsel = args->evsel;
>   	size_t size = privsize + sizeof(*al);
> +	int nr = 1;
> +
> +	if (perf_evsel__is_group_event(evsel))
> +		nr = evsel->nr_members;
> +
> +	size += sizeof(al->samples[0]) * nr;
>
>   	al = zalloc(size);
>   	if (al) {
> @@ -910,6 +917,7 @@ annotation_line__new(struct annotate_args *args, size_t privsize)
>   		al->offset     = args->offset;
>   		al->line       = strdup(args->line);
>   		al->line_nr    = args->line_nr;
> +		al->samples_nr = nr;
>   	}
>
>   	return al;
> diff --git a/tools/perf/util/annotate.h b/tools/perf/util/annotate.h
> index a02a2bf4f2ab..9c722a7e5f6d 100644
> --- a/tools/perf/util/annotate.h
> +++ b/tools/perf/util/annotate.h
> @@ -58,6 +58,16 @@ bool ins__is_fused(struct arch *arch, const char *ins1, const char *ins2);
>
>   struct annotation;
>
> +struct sym_hist_entry {
> +	u64		nr_samples;
> +	u64		period;
> +};
> +
> +struct annotation_data {
> +	double			 percent;
> +	struct sym_hist_entry	 he;
> +};
> +
>   struct annotation_line {
>   	struct list_head	 node;
>   	struct rb_node		 rb_node;
> @@ -67,6 +77,8 @@ struct annotation_line {
>   	float			 ipc;
>   	u64			 cycles;
>   	size_t			 privsize;
> +	int			 samples_nr;
> +	struct annotation_data	 samples[0];
>   };
>
>   struct disasm_line {
> @@ -87,11 +99,6 @@ static inline bool disasm_line__has_offset(const struct disasm_line *dl)
>   	return dl->ops.target.offset_avail;
>   }
>
> -struct sym_hist_entry {
> -	u64		nr_samples;
> -	u64		period;
> -};
> -
>   void disasm_line__free(struct disasm_line *dl);
>   struct annotation_line*
>   annotation_line__next(struct annotation_line *pos, struct list_head *head);