linux-kernel - Re: [linux-next-20130422] Bug in SLAB?

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <0000013e6b90e65e-e0e184d9-7da5-4873-9572-3b40958552e2-000000@email.amazonses.com>
Date:	Fri, 3 May 2013 18:04:18 +0000
From:	Christoph Lameter <cl@...ux.com>
To:	Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>
cc:	glommer@...allels.com, penberg@...nel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [linux-next-20130422] Bug in SLAB?

Enabling various debugging options increases the size of structures and
the subslab handling in SLABs kmem_cache_create will start to fail.


Here is a fix for that:

Subject: Fix bootstrap creation of kmalloc caches

For SLAB the kmalloc caches must be created in ascending sizes
in order for the OFF_SLAB sub-slab cache to work properly.

Create the non power of two caches immediately after the prior power
of two kmalloc cache. Do not create the non power of two caches
before all other caches.

Signed-off-by: Christoph Lamete <cl@...ux.com>

Index: linux/mm/slab_common.c
===================================================================
--- linux.orig/mm/slab_common.c	2013-05-03 11:16:45.764382372 -0500
+++ linux/mm/slab_common.c	2013-05-03 12:59:40.431797020 -0500
@@ -444,18 +444,24 @@ void __init create_kmalloc_caches(unsign
 		for (i = 128 + 8; i <= 192; i += 8)
 			size_index[size_index_elem(i)] = 8;
 	}
-	/* Caches that are not of the two-to-the-power-of size */
-	if (KMALLOC_MIN_SIZE <= 32 && !kmalloc_caches[1])
-		kmalloc_caches[1] = create_kmalloc_cache(NULL, 96, flags);
-
-	if (KMALLOC_MIN_SIZE <= 64 && !kmalloc_caches[2])
-		kmalloc_caches[2] = create_kmalloc_cache(NULL, 192, flags);
-
-	for (i = KMALLOC_SHIFT_LOW; i < KMALLOC_SHIFT_HIGH; i++)
-		if (!kmalloc_caches[i])
+	for (i = KMALLOC_SHIFT_LOW; i < KMALLOC_SHIFT_HIGH; i++) {
+		if (!kmalloc_caches[i]) {
 			kmalloc_caches[i] = create_kmalloc_cache(NULL,
 							1 << i, flags);

+			/*
+			 * Caches that are not of the two-to-the-power-of size.
+			 * These have to be created immediately after the
+			 * earlier power of two caches
+			 */
+			if (KMALLOC_MIN_SIZE <= 32 && !kmalloc_caches[1] && i == 6)
+				kmalloc_caches[1] = create_kmalloc_cache(NULL, 96, flags);
+
+			if (KMALLOC_MIN_SIZE <= 64 && !kmalloc_caches[2] && i == 7)
+				kmalloc_caches[2] = create_kmalloc_cache(NULL, 192, flags);
+		}
+	}
+
 	/* Kmalloc array is now usable */
 	slab_state = UP;

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/