Patch "perf diff: Fix segfault on 'perf diff -o N' option" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

perf diff: Fix segfault on 'perf diff -o N' option

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
perf-diff-fix-segfault-on-perf-diff-o-n-option.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Namhyung Kim <[email protected]>
Date: Wed, 18 Jan 2017 14:14:56 +0900
Subject: perf diff: Fix segfault on 'perf diff -o N' option

From: Namhyung Kim <[email protected]>

commit 8381cdd0e32dd748bd34ca3ace476949948bd793 upstream.

The -o/--order option is to select column number to sort a diff result.

It does the job by adding a hpp field at the beginning of the sort list. But it should not be added to the output field list as it has no callbacks required by a output field.

During the setup_sorting(), the perf_hpp__setup_output_field() appends the given sort keys to the output field if it's not there already.

Originally it was checked by fmt->list being non-empty. But commit 3f931f2c4274 ("perf hists: Make hpp setup function generic") changed it to check the ->equal callback.

Anyways, we don't need to add the pseudo hpp field to the output field list since it won't be used for output. So just skip fields if they have no ->color or ->entry callbacks.

---
 tools/perf/ui/hist.c |    4 ++++
 1 file changed, 4 insertions(+)

@@ -566,6 +566,10 @@ void perf_hpp__setup_output_field(struct
 	perf_hpp_list__for_each_sort_list(list, fmt) {
 		struct perf_hpp_fmt *pos;
 
+		/* skip sort-only fields ("sort_compute" in perf diff) */
+		if (!fmt->entry && !fmt->color)
+			continue;
+
 		perf_hpp_list__for_each_format(list, pos) {
 			if (fmt_equal(fmt, pos))
 				goto next;

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/perf-diff-fix-segfault-on-perf-diff-o-n-option.patch queue-4.9/perf-diff-fix-o-order-option-behavior-again.patch