Re: [PATCH] perf report: Fix segfault with '-F phys_daddr'

[Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>]

Em Tue, Nov 12, 2019 at 11:19:46AM +0530, Ravi Bangoria escreveu:
> If perf.data file is not recorded with mem-info, adding 'phys_daddr'
> to output field in perf report results in segfault. Fix that.
> 
> Before:
>   $ ./perf record ls
>   $ ./perf report -F +phys_daddr
>   Segmentation fault (core dumped)
> 
> After:
>   $ ./perf report -F +phys_daddr
>   Samples: 11  of event 'cycles:u', Event count (approx.): 1485821
>   Overhead  Data Physical Address  Command  Shared Object  Symbol
>     22.57%  [.] 0000000000000000   ls       libc-2.29.so   [.] __strcoll_l
>     21.87%  [.] 0000000000000000   ls       ld-2.29.so     [.] _dl_relocate_object
>     ...

Shouldn't we instead just bail out and state that this isn't possible
and leave the user wondering why what was asked isn't presented?

- Arnaldo
 
> Fixes: 8780fb25ab06 ("perf sort: Add sort option for physical address")
> Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
> ---
>  tools/perf/util/sort.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/perf/util/sort.c b/tools/perf/util/sort.c
> index 43d1d410854a..c2430676e569 100644
> --- a/tools/perf/util/sort.c
> +++ b/tools/perf/util/sort.c
> @@ -1413,7 +1413,7 @@ static int hist_entry__phys_daddr_snprintf(struct hist_entry *he, char *bf,
>  	size_t ret = 0;
>  	size_t len = BITS_PER_LONG / 4;
>  
> -	addr = he->mem_info->daddr.phys_addr;
> +	addr = he->mem_info ? he->mem_info->daddr.phys_addr : 0;
>  
>  	ret += repsep_snprintf(bf + ret, size - ret, "[%c] ", he->level);
>  
> -- 
> 2.21.0

-- 

- Arnaldo