Re: perf: commit 55b4462 causes perf record to hang

Thomas Gleixner
2011-01-11T08:29:02Z

On Mon, 10 Jan 2011, Arnaldo Carvalho de Melo wrote:

> Em Mon, Jan 10, 2011 at 11:47:43AM -0700, David Ahern escreveu:
> > With latest version of perf-core branch, a variant of perf record hangs:
> > # /tmp/build-perf/perf record -v -e cs -fo /tmp/perf.data -- sleep 1
> > [ perf record: Captured and wrote 0.003 MB /tmp/perf.data (~120 samples) ]
> >
> > It sits there forever. Back trace is:
> >
> > (gdb) bt
> > #0 0x0000000000447658 in __perf_session__process_events (session=0xab9500, data_offset=208, data_size=2896, file_size=3104, ops=0x685580) at util/session.c:1006
> > #1 0x00000000004107dd in process_buildids () at builtin-record.c:466
> > #2 0x000000000041084d in atexit_header () at builtin-record.c:477
>
> > git bisect traced the hang to
> >
> > commit 55b44629f599a2305265ae9c77f9d9bcfd6ddc17
> > Author: Thomas Gleixner <tglx@linutronix.de>
> > Date: Tue Nov 30 17:49:46 2010 +0000
>
> Can you try with this patch, not reverting tglx's patch?
>
> diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
> index 6fb4694..313dac2 100644
> --- a/tools/perf/util/session.c
> +++ b/tools/perf/util/session.c
> @@ -1007,7 +1007,7 @@ more:
> if (size == 0)
> size = 8;
>
> - if (head + event->header.size >= mmap_size) {
> + if (head + event->header.size > mmap_size) {
> if (mmaps[map_idx]) {
> munmap(mmaps[map_idx], mmap_size);
> mmaps[map_idx] = NULL;
>

/me feels stupid

tglx