perf record: Fix filemap pathname parsing in /proc/pid/maps

Looking backward for the first space from the end of a line in
/proc/pid/maps does not find the start of the pathname of the mapped
file if it contains a space.

Since the only slashes we have in this file occur in the (absolute!)
pathname column of file mappings, looking for the first slash in a
line is a safe method to find the name.
Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Cc: Stefani Seibold <stefani@seibold.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20090624190835.GA25548@cmpxchg.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

tools/perf/builtin-record.c

@@ -306,12 +306,11 @@ static void pid_synthesize_mmap_samples(pid_t pid)
 			continue;
 		pbf += n + 3;
 		if (*pbf == 'x') { /* vm_exec */
-			char *execname = strrchr(bf, ' ');
+			char *execname = strchr(bf, '/');
 
-			if (execname == NULL || execname[1] != '/')
+			if (execname == NULL)
 				continue;
 
-			execname += 1;
 			size = strlen(execname);
 			execname[size - 1] = '\0'; /* Remove \n */
 			memcpy(mmap_ev.filename, execname, size);