Patch "perf annotate: Fix a bug following symbolic link of a build-id file" 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 annotate: Fix a bug following symbolic link of a build-id file

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-annotate-fix-a-bug-following-symbolic-link-of-a-build-id-file.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: Taeung Song <[email protected]>
Date: Mon, 27 Mar 2017 16:10:36 +0900
Subject: perf annotate: Fix a bug following symbolic link of a build-id file

From: Taeung Song <[email protected]>

[ Upstream commit 6ebd2547dd24daf95a21b2bc59931de8502afcc3 ]

It is wrong way to read link name from a build-id file. Because a build-id file is not anymore a symbolic link but build-id directory of it is symbolic link, so fix it.

For example, if build-id file name gotten from
dso__build_id_filename() is as below,

/root/.debug/.build-id/4f/75c7d197c951659d1c1b8b5fd49bcdf8f3f8b1/elf

To correctly read link name of build-id, use the build-id dir path that is a symbolic link, instead of the above build-id file name like below.

/root/.debug/.build-id/4f/75c7d197c951659d1c1b8b5fd49bcdf8f3f8b1

---
 tools/perf/util/annotate.c |   10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

@@ -1250,6 +1250,7 @@ static int dso__disassemble_filename(str
 {
 	char linkname[PATH_MAX];
 	char *build_id_filename;
+	char *build_id_path = NULL;
 
 	if (dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS &&
 	    !dso__is_kcore(dso))

@@ -1265,8 +1266,14 @@ static int dso__disassemble_filename(str
 		goto fallback;
 	}
 
+	build_id_path = strdup(filename);
+	if (!build_id_path)
+		return -1;
+
+	dirname(build_id_path);
+
 	if (dso__is_kcore(dso) ||
-	    readlink(filename, linkname, sizeof(linkname)) < 0 ||
+	    readlink(build_id_path, linkname, sizeof(linkname)) < 0 ||
 	    strstr(linkname, DSO__NAME_KALLSYMS) ||
 	    access(filename, R_OK)) {
 fallback:

@@ -1278,6 +1285,7 @@ fallback:
 		__symbol__join_symfs(filename, filename_size, dso->long_name);
 	}
 
+	free(build_id_path);
 	return 0;
 }
 

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

queue-4.9/perf-annotate-fix-a-bug-following-symbolic-link-of-a-build-id-file.patch