linux-kernel - Re: [patch 00/26] Current slab allocator / SLUB patch queue

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: <Pine.LNX.4.64.0706180936280.4751@schroedinger.engr.sgi.com>
Date:	Mon, 18 Jun 2007 09:46:11 -0700 (PDT)
From:	Christoph Lameter <clameter@....com>
To:	Michal Piotrowski <michal.k.k.piotrowski@...il.com>
cc:	akpm@...ux-foundation.org, linux-kernel@...r.kernel.org,
	linux-mm@...ck.org, Pekka Enberg <penberg@...helsinki.fi>,
	suresh.b.siddha@...el.com
Subject: Re: [patch 00/26] Current slab allocator / SLUB patch queue

On Mon, 18 Jun 2007, Michal Piotrowski wrote:

> Result:
> 
> [  212.247759] WARNING: at lib/vsprintf.c:280 vsnprintf()
> [  212.253263]  [<c04052ad>] dump_trace+0x63/0x1eb
> [  212.259042]  [<c040544f>] show_trace_log_lvl+0x1a/0x2f
> [  212.266672]  [<c040608d>] show_trace+0x12/0x14
> [  212.271622]  [<c04060a5>] dump_stack+0x16/0x18
> [  212.276663]  [<c050d512>] vsnprintf+0x6b/0x48c
> [  212.281325]  [<c050d9f0>] scnprintf+0x20/0x2d
> [  212.286707]  [<c0508dbc>] bitmap_scnlistprintf+0xa8/0xec
> [  212.292508]  [<c0480d40>] list_locations+0x24c/0x2a2
> [  212.298241]  [<c0480dde>] alloc_calls_show+0x1f/0x26
> [  212.303459]  [<c047e72e>] slab_attr_show+0x1c/0x20
> [  212.309469]  [<c04c1cf9>] sysfs_read_file+0x94/0x105
> [  212.315519]  [<c0485933>] vfs_read+0xcf/0x158
> [  212.320215]  [<c0485d99>] sys_read+0x3d/0x72
> [  212.327539]  [<c040420c>] syscall_call+0x7/0xb
> [  212.332203]  [<b7f74410>] 0xb7f74410
> [  212.336229]  =======================
> 
> Unfortunately, I don't know which file was cat'ed

The dump shows that it was alloc_calls. But the issue is not related to 
this patchset.

Looks like we overflowed the buffer available for /sys output. The calls 
in list_location to format cpulist and node lists attempt to allow very
long lists by trying to calculate how many bytes are remaining in the 
page. If we are beyond the space left over by them then we may pass a
negative size to the scn_printf functions.

So we need to check first if there are enough bytes remaining before
doing the calculation of how many remaining bytes can be used to
format these lists.

Does this patch fix the issue?

Index: linux-2.6.22-rc4-mm2/mm/slub.c
===================================================================
--- linux-2.6.22-rc4-mm2.orig/mm/slub.c	2007-06-18 09:37:41.000000000 -0700
+++ linux-2.6.22-rc4-mm2/mm/slub.c	2007-06-18 09:44:38.000000000 -0700
@@ -3649,13 +3649,15 @@ static int list_locations(struct kmem_ca
 			n += sprintf(buf + n, " pid=%ld",
 				l->min_pid);
 
-		if (num_online_cpus() > 1 && !cpus_empty(l->cpus)) {
+		if (num_online_cpus() > 1 && !cpus_empty(l->cpus) &&
+				n < PAGE_SIZE - n - 57) {
 			n += sprintf(buf + n, " cpus=");
 			n += cpulist_scnprintf(buf + n, PAGE_SIZE - n - 50,
 					l->cpus);
 		}
 
-		if (num_online_nodes() > 1 && !nodes_empty(l->nodes)) {
+		if (num_online_nodes() > 1 && !nodes_empty(l->nodes) &&
+				n < PAGE_SIZE - n - 57) {
 			n += sprintf(buf + n, " nodes=");
 			n += nodelist_scnprintf(buf + n, PAGE_SIZE - n - 50,
 					l->nodes);





-
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/