perf report: Fix kernel symbol resolution

kallsyms have just the symbol start, so we need to read two lines
to get the len.

[ Impact: fix incorrect kernel symbol display in perf report ]

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: John Kacur <jkacur@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 21 insertions, 5 deletions

diff --git a/Documentation/perf_counter/builtin-report.c b/Documentation/perf_counter/builtin-report.c
index 697f960495fc..b19b893d4ff5 100644
--- a/Documentation/perf_counter/builtin-report.c
+++ b/Documentation/perf_counter/builtin-report.c
@@ -360,9 +360,17 @@ static int load_kallsyms(void)
         char *line = NULL;
         size_t n;
 
+        if (getline(&line, &n, file) < 0 || !line)
+                goto out_delete_dso;
+
+        unsigned long long previous_start;
+        char c, previous_symbf[4096];
+        if (sscanf(line, "%llx %c %s", &previous_start, &c, previous_symbf) != 3)
+                goto out_delete_line;
+
         while (!feof(file)) {
                 unsigned long long start;
-                char c, symbf[4096];
+                char symbf[4096];
 
                 if (getline(&line, &n, file) < 0)
                         break;
@@ -371,12 +379,18 @@ static int load_kallsyms(void)
                         goto out_delete_dso;
 
                 if (sscanf(line, "%llx %c %s", &start, &c, symbf) == 3) {
-                        struct symbol *sym = symbol__new(start, 0x1000000, symbf);
+                        if (start > previous_start) {
+                                struct symbol *sym = symbol__new(previous_start,
+                                                                 start - previous_start,
+                                                                 previous_symbf);
 
-                        if (sym == NULL)
-                                goto out_delete_dso;
+                                if (sym == NULL)
+                                        goto out_delete_dso;
 
-                        dso__insert_symbol(kernel_dso, sym);
+                                dso__insert_symbol(kernel_dso, sym);
+                                previous_start = start;
+                                strcpy(previous_symbf, symbf);
+                        }
                 }
         }
 
@@ -385,6 +399,8 @@ static int load_kallsyms(void)
         fclose(file);
         return 0;
 
+out_delete_line:
+        free(line);
 out_delete_dso:
         dso__delete(kernel_dso);
         return -1;