Re: perf_evlist__filter_pollfd() in trace__run()

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

Em Fri, Jan 30, 2015 at 12:16:11PM -0800, Sukadev Bhattiprolu escreveu:
> Arnaldo Carvalho de Melo [acme@kernel.org] wrote:
> | Em Thu, Jan 29, 2015 at 03:55:22PM -0800, Sukadev Bhattiprolu escreveu:
> | > Should there be another check to before reading the mmap again ?
> | 
> | Possibly, checking, but a similar algorithm should be in place for
> | 'record', do you see any problems there? I.e. with 'perf record sleep
> | 1'?
> 
> No, I don't see the failure with perf record in several hundred attempts.
> (both the distro and latest perf-core versions work ok).

Ok, so its a matter of comparing what both are doing, will try.
 
> | > I must add that I don't get the SIGSEGV on recent perf-core and the
> | > system where we get the crash, first runs into the following
> | > errors that we are still looking into (maybe related to "ppc64le"
> | > architecture).
> 
> With recent perf core I did not get the SIGSEGV (or the syscall translation
> failures below) on a different system.
> 
> But on this system, a power KVM guest, I get both errors even with latest 
> perf core (commit c52686f9f88).
> 
> | > 
> | > 	Problems reading syscall 45 information
> | > 	Problems reading syscall 5 information
> | > 	Problems reading syscall 5 information
> | > 	Problems reading syscall 108 information
> | > 	Problems reading syscall 108 information
> | > 	Problems reading syscall 90 information
> | > 	Problems reading syscall 90 information
> | > 	Problems reading syscall 6 information
> | > 
> | > Unlike the SIGSEGV, these errors occur always.
> 
> Most likely this syscall number translation is due to the
> 
> https://fedorahosted.org/audit/browser/trunk/lib/machinetab.h 
> 
> missing this change set 1013, which added support for ppc64le.

We have to improve that message to mention that perhaps a newer
audit-libs package is required.

- Arnaldo