Subject: Patch "perf event: Check ref_reloc_sym before using it" has been added to the 4.9-stable tree

From: <[email-masked]>
Date: Wed, 25 Nov 2020 12:48:22 +0100

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

    perf event: Check ref_reloc_sym before using it

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-event-check-ref_reloc_sym-before-using-it.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-masked]> know about it.

>From e9a6882f267a8105461066e3ea6b4b6b9be1b807 Mon Sep 17 00:00:00 2001
From: Igor Lubashev <[email-masked]>
Date: Mon, 26 Aug 2019 21:39:12 -0400
Subject: perf event: Check ref_reloc_sym before using it

From: Igor Lubashev <[email-masked]>

commit e9a6882f267a8105461066e3ea6b4b6b9be1b807 upstream.

Check for ref_reloc_sym before using it instead of checking
symbol_conf.kptr_restrict and relying solely on that check.

Reported-by: Mathieu Poirier <[email-masked]>
Signed-off-by: Igor Lubashev <[email-masked]>
Tested-by: Mathieu Poirier <[email-masked]>
Cc: Alexander Shishkin <[email-masked]>
Cc: Alexey Budankov <[email-masked]>
Cc: James Morris <[email-masked]>
Cc: Jiri Olsa <[email-masked]>
Cc: Namhyung Kim <[email-masked]>
Cc: Peter Zijlstra <[email-masked]>
Cc: Suzuki Poulouse <[email-masked]>
Cc: [email-masked]
Link: http://lkml.kernel.org/r/[email-masked]
Signed-off-by: Arnaldo Carvalho de Melo <[email-masked]>
Cc: Alexander Dahl <[email-masked]>
Signed-off-by: Greg Kroah-Hartman <[email-masked]>

---
 tools/perf/util/event.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

--- a/tools/perf/util/event.c
+++ b/tools/perf/util/event.c
@@ -682,11 +682,13 @@ int perf_event__synthesize_kernel_mmap(s
 	int err;
 	union perf_event *event;
 
-	if (symbol_conf.kptr_restrict)
-		return -1;
 	if (map == NULL)
 		return -1;
 
+	kmap = map__kmap(map);
+	if (!kmap->ref_reloc_sym)
+		return -1;
+
 	/*
 	 * We should get this from /sys/kernel/sections/.text, but till that is
 	 * available use this, and after it is use this as a fallback for older
@@ -710,7 +712,6 @@ int perf_event__synthesize_kernel_mmap(s
 		event->header.misc = PERF_RECORD_MISC_GUEST_KERNEL;
 	}
 
-	kmap = map__kmap(map);
 	size = snprintf(event->mmap.filename, sizeof(event->mmap.filename),
 			"%s%s", mmap_name, kmap->ref_reloc_sym->name) + 1;
 	size = PERF_ALIGN(size, sizeof(u64));

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

queue-4.9/perf-event-check-ref_reloc_sym-before-using-it.patch

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