1 files changed, 43 insertions, 0 deletions

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index aac34c2a410b..c42872ed82ac 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -326,6 +326,7 @@ EXPORT_SYMBOL(vmalloc_to_pfn);
 /*** Global kva allocator ***/
 
 #define DEBUG_AUGMENT_PROPAGATE_CHECK 0
+#define DEBUG_AUGMENT_LOWEST_MATCH_CHECK 0
 
 #define VM_LAZY_FREE    0x02
 #define VM_VM_AREA      0x04
@@ -834,6 +835,44 @@ find_vmap_lowest_match(unsigned long size,
         return NULL;
 }
 
+#if DEBUG_AUGMENT_LOWEST_MATCH_CHECK
+#include <linux/random.h>
+
+static struct vmap_area *
+find_vmap_lowest_linear_match(unsigned long size,
+        unsigned long align, unsigned long vstart)
+{
+        struct vmap_area *va;
+
+        list_for_each_entry(va, &free_vmap_area_list, list) {
+                if (!is_within_this_va(va, size, align, vstart))
+                        continue;
+
+                return va;
+        }
+
+        return NULL;
+}
+
+static void
+find_vmap_lowest_match_check(unsigned long size)
+{
+        struct vmap_area *va_1, *va_2;
+        unsigned long vstart;
+        unsigned int rnd;
+
+        get_random_bytes(&rnd, sizeof(rnd));
+        vstart = VMALLOC_START + rnd;
+
+        va_1 = find_vmap_lowest_match(size, 1, vstart);
+        va_2 = find_vmap_lowest_linear_match(size, 1, vstart);
+
+        if (va_1 != va_2)
+                pr_emerg("not lowest: t: 0x%p, l: 0x%p, v: 0x%lx\n",
+                        va_1, va_2, vstart);
+}
+#endif
+
 enum fit_type {
         NOTHING_FIT = 0,
         FL_FIT_TYPE = 1,        /* full fit */
@@ -976,6 +1015,10 @@ __alloc_vmap_area(unsigned long size, unsigned long align,
         if (ret)
                 return vend;
 
+#if DEBUG_AUGMENT_LOWEST_MATCH_CHECK
+        find_vmap_lowest_match_check(size);
+#endif
+
         return nva_start_addr;
 }