Don't assume a default (currently 15) value for preloaded klds when

loading hwpmc, but calculate at runtime and allocate the necessary space.
Also the current logic is wrong as it can lead to an endless loop.

Sponsored by:   Sandvine Incorporated
Reported by:    Ryan Stone <rstone at sandvine dot com>
Tested by:      Giovanni Trematerra
                <giovanni dot trematerra at gmail dot com>
Approved by:	re (kib)

1 files changed, 19 insertions, 39 deletions

diff --git a/sys/kern/kern_linker.c b/sys/kern/kern_linker.c
index fbfd6cf..9775059 100644
--- a/sys/kern/kern_linker.c
+++ b/sys/kern/kern_linker.c
@@ -1927,61 +1927,41 @@ linker_basename(const char *path)
 }
 
 #ifdef HWPMC_HOOKS
-
-struct hwpmc_context {
-	int	nobjects;
-	int	nmappings;
-	struct pmckern_map_in *kobase;
-};
-
-static int
-linker_hwpmc_list_object(linker_file_t lf, void *arg)
-{
-	struct hwpmc_context *hc;
-
-	hc = arg;
-
-	/* If we run out of mappings, fail. */
-	if (hc->nobjects >= hc->nmappings)
-		return (1);
-
-	/* Save the info for this linker file. */
-	hc->kobase[hc->nobjects].pm_file = lf->filename;
-	hc->kobase[hc->nobjects].pm_address = (uintptr_t)lf->address;
-	hc->nobjects++;
-	return (0);
-}
-
 /*
  * Inform hwpmc about the set of kernel modules currently loaded.
  */
 void *
 linker_hwpmc_list_objects(void)
 {
-	struct hwpmc_context hc;
+	linker_file_t lf;
+	struct pmckern_map_in *kobase;
+	int i, nmappings;
 
-	hc.nmappings = 15;	/* a reasonable default */
+	nmappings = 0;
+	KLD_LOCK();
+	TAILQ_FOREACH(lf, &linker_files, link)
+		nmappings++;
 
- retry:
-	/* allocate nmappings+1 entries */
-	hc.kobase = malloc((hc.nmappings + 1) * sizeof(struct pmckern_map_in),
+	/* Allocate nmappings + 1 entries. */
+	kobase = malloc((nmappings + 1) * sizeof(struct pmckern_map_in),
 	    M_LINKER, M_WAITOK | M_ZERO);
+	i = 0;
+	TAILQ_FOREACH(lf, &linker_files, link) {
 
-	hc.nobjects = 0;
-	if (linker_file_foreach(linker_hwpmc_list_object, &hc) != 0) {
-		hc.nmappings = hc.nobjects;
-		free(hc.kobase, M_LINKER);
-		goto retry;
+		/* Save the info for this linker file. */
+		kobase[i].pm_file = lf->filename;
+		kobase[i].pm_address = (uintptr_t)lf->address;
+		i++;
 	}
+	KLD_UNLOCK();
 
-	KASSERT(hc.nobjects > 0, ("linker_hpwmc_list_objects: no kernel "
-		"objects?"));
+	KASSERT(i > 0, ("linker_hpwmc_list_objects: no kernel objects?"));
 
 	/* The last entry of the malloced area comprises of all zeros. */
-	KASSERT(hc.kobase[hc.nobjects].pm_file == NULL,
+	KASSERT(kobase[i].pm_file == NULL,
 	    ("linker_hwpmc_list_objects: last object not NULL"));
 
-	return ((void *)hc.kobase);
+	return ((void *)kobase);
 }
 #endif