perf report: null ptr dereference in utils/env.c

perf report: null ptr dereference in utils/env.c

[Odzioba, Lukasz]

Hi,
Am I the only one getting segfaults in perf report (4.8-rc8/4.9rc-1)?
It happens simply when I try to exit it.

Program received signal SIGSEGV, Segmentation fault.
perf_env__exit (env=env@entry=0x1fc4d00) at util/env.c:25
(...)
(gdb) list
(...)

24              for (i = 0; i < env->nr_numa_nodes; i++)
25                      cpu_map__put(env->numa_nodes[i].map);
26              zfree(&env->numa_nodes);
 
 (gdb) print env->nr_numa_nodes
$1 = 2
 (gdb) print env->numa_nodes
$2 = (struct numa_node *) 0x0    

This line was introduced in the following patch:
https://patchwork.kernel.org/patch/9213995/

Thanks,
Lukas

Re: perf report: null ptr dereference in utils/env.c

[Jiri Olsa]

On Tue, Oct 18, 2016 at 04:13:45PM +0000, Odzioba, Lukasz wrote:
> Hi,
> Am I the only one getting segfaults in perf report (4.8-rc8/4.9rc-1)?
> It happens simply when I try to exit it.
> 
> Program received signal SIGSEGV, Segmentation fault.
> perf_env__exit (env=env@entry=0x1fc4d00) at util/env.c:25
> (...)
> (gdb) list
> (...)
> 
> 24              for (i = 0; i < env->nr_numa_nodes; i++)
> 25                      cpu_map__put(env->numa_nodes[i].map);
> 26              zfree(&env->numa_nodes);
>  
>  (gdb) print env->nr_numa_nodes
> $1 = 2
>  (gdb) print env->numa_nodes
> $2 = (struct numa_node *) 0x0    
> 
> This line was introduced in the following patch:
> https://patchwork.kernel.org/patch/9213995/

could you please try with Arnaldo's current perf/urgent branch
that has following patch:
  f957a5308dbb perf header: Set nr_numa_nodes only when we parsed all the data

is that ppc machine? how did you generate the perf.data?

thanks,
jirka

RE: perf report: null ptr dereference in utils/env.c

[Odzioba, Lukasz]

On Wednesday, October 19, 2016 12:04 AM, Jiri Olsa wrote:
> could you please try with Arnaldo's current perf/urgent branch
> that has following patch:
> f957a5308dbb perf header: Set nr_numa_nodes only when we parsed all the data
>
> is that ppc machine? how did you generate the perf.data?

It does make the problem go away.

x86_64, generated by:
# perf record -- ls
# perf report

Thanks for help,
Lukas

Re: perf report: null ptr dereference in utils/env.c

[Jiri Olsa]

On Wed, Oct 19, 2016 at 08:29:41AM +0000, Odzioba, Lukasz wrote:
> On Wednesday, October 19, 2016 12:04 AM, Jiri Olsa wrote:
> > could you please try with Arnaldo's current perf/urgent branch
> > that has following patch:
> > f957a5308dbb perf header: Set nr_numa_nodes only when we parsed all the data
> >
> > is that ppc machine? how did you generate the perf.data?
> 
> It does make the problem go away.
> 
> x86_64, generated by:
> # perf record -- ls
> # perf report

hum, I still can't reproduce this.. could you please send
me your kernel's config file?

thanks,
jirka