tunnels: do not assume mac header is set in skb_tunnel_check_pmtu()

[mirror_ubuntu-jammy-kernel.git] / mm / util.c

diff --git a/mm/util.c b/mm/util.c
index bacabe446906558f6c3b1d4ff7801d187c64c256..3073de05c2bd42da51cdc82a70b0a048a4ca9f51 100644 (file)
--- a/mm/util.c
+++ b/mm/util.c
@@ -343,6 +343,38 @@ unsigned long randomize_stack_top(unsigned long stack_top)
 #endif
 }
 
+/**
+ * randomize_page - Generate a random, page aligned address
+ * @start:     The smallest acceptable address the caller will take.
+ * @range:     The size of the area, starting at @start, within which the
+ *             random address must fall.
+ *
+ * If @start + @range would overflow, @range is capped.
+ *
+ * NOTE: Historical use of randomize_range, which this replaces, presumed that
+ * @start was already page aligned.  We now align it regardless.
+ *
+ * Return: A page aligned address within [start, start + range).  On error,
+ * @start is returned.
+ */
+unsigned long randomize_page(unsigned long start, unsigned long range)
+{
+       if (!PAGE_ALIGNED(start)) {
+               range -= PAGE_ALIGN(start) - start;
+               start = PAGE_ALIGN(start);
+       }
+
+       if (start > ULONG_MAX - range)
+               range = ULONG_MAX - start;
+
+       range >>= PAGE_SHIFT;
+
+       if (range == 0)
+               return start;
+
+       return start + (get_random_long() % range << PAGE_SHIFT);
+}
+
 #ifdef CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
 unsigned long arch_randomize_brk(struct mm_struct *mm)
 {
@@ -594,8 +626,10 @@ void *kvmalloc_node(size_t size, gfp_t flags, int node)
                return ret;
 
        /* Don't even allow crazy sizes */
-       if (WARN_ON_ONCE(size > INT_MAX))
+       if (unlikely(size > INT_MAX)) {
+               WARN_ON_ONCE(!(flags & __GFP_NOWARN));
                return NULL;
+       }
 
        return __vmalloc_node(size, 1, flags, node,
                        __builtin_return_address(0));