Commit 85c3e4a5 authored by Geert Uytterhoeven's avatar Geert Uytterhoeven Committed by Linus Torvalds
Browse files

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: ad67b74d ("printk: hash addresses printed with %p")
Signed-off-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Acked-by: default avatarChristoph Lameter <cl@linux.com>
Acked-by: default avatarLinus 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c24ad77d

mm/slab.c

+10 −13
Original line number Diff line number Diff line
@@ -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)

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