1 files changed, 49 insertions, 1 deletions

diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c
index 6a7e273a514a..f1479eeef7da 100644
--- a/tools/perf/util/build-id.c
+++ b/tools/perf/util/build-id.c
@@ -166,6 +166,50 @@ char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size)
         return build_id__filename(build_id_hex, bf, size);
 }
 
+bool dso__build_id_is_kmod(const struct dso *dso, char *bf, size_t size)
+{
+        char *id_name, *ch;
+        struct stat sb;
+
+        id_name = dso__build_id_filename(dso, bf, size);
+        if (!id_name)
+                goto err;
+        if (access(id_name, F_OK))
+                goto err;
+        if (lstat(id_name, &sb) == -1)
+                goto err;
+        if ((size_t)sb.st_size > size - 1)
+                goto err;
+        if (readlink(id_name, bf, size - 1) < 0)
+                goto err;
+
+        bf[sb.st_size] = '\0';
+
+        /*
+         * link should be:
+         * ../../lib/modules/4.4.0-rc4/kernel/net/ipv4/netfilter/nf_nat_ipv4.ko/a09fe3eb3147dafa4e3b31dbd6257e4d696bdc92
+         */
+        ch = strrchr(bf, '/');
+        if (!ch)
+                goto err;
+        if (ch - 3 < bf)
+                goto err;
+
+        return strncmp(".ko", ch - 3, 3) == 0;
+err:
+        /*
+         * If dso__build_id_filename work, get id_name again,
+         * because id_name points to bf and is broken.
+         */
+        if (id_name)
+                id_name = dso__build_id_filename(dso, bf, size);
+        pr_err("Invalid build id: %s\n", id_name ? :
+                                         dso->long_name ? :
+                                         dso->short_name ? :
+                                         "[unknown]");
+        return false;
+}
+
 #define dsos__for_each_with_build_id(pos, head) \
         list_for_each_entry(pos, head, node)    \
                 if (!pos->has_build_id)         \
@@ -211,6 +255,7 @@ static int machine__write_buildid_table(struct machine *machine, int fd)
         dsos__for_each_with_build_id(pos, &machine->dsos.head) {
                 const char *name;
                 size_t name_len;
+                bool in_kernel = false;
 
                 if (!pos->hit)
                         continue;
@@ -227,8 +272,11 @@ static int machine__write_buildid_table(struct machine *machine, int fd)
                         name_len = pos->long_name_len + 1;
                 }
 
+                in_kernel = pos->kernel ||
+                                is_kernel_module(name,
+                                        PERF_RECORD_MISC_CPUMODE_UNKNOWN);
                 err = write_buildid(name, name_len, pos->build_id, machine->pid,
-                                    pos->kernel ? kmisc : umisc, fd);
+                                    in_kernel ? kmisc : umisc, fd);
                 if (err)
                         break;
         }