mm/slab.c: do not hash pointers when debugging slab

If CONFIG_DEBUG_SLAB/CONFIG_DEBUG_SLAB_LEAK are enabled, the slab code
prints extra debug information when e.g.  corruption is detected.  This
includes pointers, which are not very useful when hashed.

Fix this by using %px to print unhashed pointers instead where it makes
sense, and by removing the printing of a last user pointer referring to
code.

[geert+renesas@glider.be: v2]
Link: http://lkml.kernel.org/r/1513179267-2509-1-git-send-email-geert+renesas@glider.be
Link: http://lkml.kernel.org/r/1512641861-5113-1-git-send-email-geert+renesas@glider.be
Fixes: ad67b74d2469d9b8 ("printk: hash addresses printed with %p")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: "Tobin C . Harding" <me@tobin.cc>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/slab.c b/mm/slab.c
index 183e996dde5ff37a8881e9c223a348de947bf890..4e51ef954026bd15e5bef41167459970976faab0 100644 (file)
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1584,11 +1584,8 @@ static void print_objinfo(struct kmem_cache *cachep, void *objp, int lines)
                       *dbg_redzone2(cachep, objp));
        }
 
-       if (cachep->flags & SLAB_STORE_USER) {
-               pr_err("Last user: [<%p>](%pSR)\n",
-                      *dbg_userword(cachep, objp),
-                      *dbg_userword(cachep, objp));
-       }
+       if (cachep->flags & SLAB_STORE_USER)
+               pr_err("Last user: (%pSR)\n", *dbg_userword(cachep, objp));
        realobj = (char *)objp + obj_offset(cachep);
        size = cachep->object_size;
        for (i = 0; i < size && lines; i += 16, lines--) {
@@ -1621,7 +1618,7 @@ static void check_poison_obj(struct kmem_cache *cachep, void *objp)
                        /* Mismatch ! */
                        /* Print header */
                        if (lines == 0) {
-                               pr_err("Slab corruption (%s): %s start=%p, len=%d\n",
+                               pr_err("Slab corruption (%s): %s start=%px, len=%d\n",
                                       print_tainted(), cachep->name,
                                       realobj, size);
                                print_objinfo(cachep, objp, 0);
@@ -1650,13 +1647,13 @@ static void check_poison_obj(struct kmem_cache *cachep, void *objp)
                if (objnr) {
                        objp = index_to_obj(cachep, page, objnr - 1);
                        realobj = (char *)objp + obj_offset(cachep);
-                       pr_err("Prev obj: start=%p, len=%d\n", realobj, size);
+                       pr_err("Prev obj: start=%px, len=%d\n", realobj, size);
                        print_objinfo(cachep, objp, 2);
                }
                if (objnr + 1 < cachep->num) {
                        objp = index_to_obj(cachep, page, objnr + 1);
                        realobj = (char *)objp + obj_offset(cachep);
-                       pr_err("Next obj: start=%p, len=%d\n", realobj, size);
+                       pr_err("Next obj: start=%px, len=%d\n", realobj, size);
                        print_objinfo(cachep, objp, 2);
                }
        }
@@ -2608,7 +2605,7 @@ static void slab_put_obj(struct kmem_cache *cachep,
        /* Verify double free bug */
        for (i = page->active; i < cachep->num; i++) {
                if (get_free_obj(page, i) == objnr) {
-                       pr_err("slab: double free detected in cache '%s', objp %p\n",
+                       pr_err("slab: double free detected in cache '%s', objp %px\n",
                               cachep->name, objp);
                        BUG();
                }
@@ -2772,7 +2769,7 @@ static inline void verify_redzone_free(struct kmem_cache *cache, void *obj)
        else
                slab_error(cache, "memory outside object was overwritten");
 
-       pr_err("%p: redzone 1:0x%llx, redzone 2:0x%llx\n",
+       pr_err("%px: redzone 1:0x%llx, redzone 2:0x%llx\n",
               obj, redzone1, redzone2);
 }
 
@@ -3078,7 +3075,7 @@ static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
                if (*dbg_redzone1(cachep, objp) != RED_INACTIVE ||
                                *dbg_redzone2(cachep, objp) != RED_INACTIVE) {
                        slab_error(cachep, "double free, or memory outside object was overwritten");
-                       pr_err("%p: redzone 1:0x%llx, redzone 2:0x%llx\n",
+                       pr_err("%px: redzone 1:0x%llx, redzone 2:0x%llx\n",
                               objp, *dbg_redzone1(cachep, objp),
                               *dbg_redzone2(cachep, objp));
                }
@@ -3091,7 +3088,7 @@ static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
                cachep->ctor(objp);
        if (ARCH_SLAB_MINALIGN &&
            ((unsigned long)objp & (ARCH_SLAB_MINALIGN-1))) {
-               pr_err("0x%p: not aligned to ARCH_SLAB_MINALIGN=%d\n",
+               pr_err("0x%px: not aligned to ARCH_SLAB_MINALIGN=%d\n",
                       objp, (int)ARCH_SLAB_MINALIGN);
        }
        return objp;
@@ -4283,7 +4280,7 @@ static void show_symbol(struct seq_file *m, unsigned long address)
                return;
        }
 #endif
-       seq_printf(m, "%p", (void *)address);
+       seq_printf(m, "%px", (void *)address);
 }
 
 static int leaks_show(struct seq_file *m, void *p)