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

[Arnaldo Carvalho de Melo <acme@ghostprotocols.net>]

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;