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

Arnaldo Carvalho de Melo
2011-01-10T20:00:58Z

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;