Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758026Ab3FTQ7v (ORCPT ); Thu, 20 Jun 2013 12:59:51 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:56847 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757862Ab3FTQ7t (ORCPT ); Thu, 20 Jun 2013 12:59:49 -0400 Message-ID: <51C334FA.6080604@gmail.com> Date: Fri, 21 Jun 2013 00:59:38 +0800 From: Zhang Yanfei User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:10.0.5) Gecko/20120607 Thunderbird/10.0.5 MIME-Version: 1.0 To: Ghennadi Procopciuc CC: akpm@linux-foundation.org, js1304@gmail.com, rientjes@google.com, minchan@kernel.org, kosaki.motohiro@jp.fujitsu.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Daniel Baluta Subject: Re: [PATCH] mm: fix overflow in alloc_vmap_area References: <1371741150-10861-1-git-send-email-unix140@gmail.com> In-Reply-To: <1371741150-10861-1-git-send-email-unix140@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6017 Lines: 152 On 06/20/2013 11:12 PM, Ghennadi Procopciuc wrote: > Inserting the following kernel module: > > > > static int simple_test_init(void) > { > size_t i, j; > void *address; > > for (i = 0 * MB; i< 60 * MB; i += 1 * MB) { > for (j = i; j< i + 1 * MB; j += KB) { > address = vmalloc(j); > vfree(address); > } > } > > return 0; > } > > > > triggers BUG at mm/vmalloc.c:310 on a x86 machine: > > [ 95.218283] Kernel BUG at c1126cdb [verbose debug info unavailable] > [ 95.218306] invalid opcode: 0000 [#1] SMP > [ 95.218324] Modules linked in: lkma_test(OF+) > [ 95.218559] Pid: 2419, comm: insmod Tainted: GF O 3.9.0+ #57 Hewlett-Packard HP Compaq 8200 Elite CMT PC/1494 > [ 95.218597] EIP: 0060:[] EFLAGS: 00010207 CPU: 3 > [ 95.218617] EIP is at __insert_vmap_area+0xfb/0x100 > [ 95.218635] EAX: f85dc000 EBX: ef05cac0 ECX: f7be08c4 EDX: 00000007 > [ 95.218657] ESI: f2ed044c EDI: c1a220b8 EBP: f027bd34 ESP: f027bd14 > [ 95.218680] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 > [ 95.218699] CR0: 80050033 CR2: b5995118 CR3: 30364000 CR4: 000407f0 > [ 95.218721] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 > [ 95.218743] DR6: ffff0ff0 DR7: 00000400 > [ 95.218758] Process insmod (pid: 2419, ti=f027a000 task=efe64010 task.ti=f027a000) > [ 95.218784] Stack: > [ 95.218792] c177b964 fecfb000 f85e2000 00000000 f85dc000 ffbfe000 f02da1c0 0007f000 > [ 95.218829] f027bd7c c112802d c177b9b0 fecfb000 01305000 ffbfe000 00000001 ef05cac0 > [ 95.218866] 00000000 00000000 f83fe000 01304fff f83fe000 ffffffff 01305000 ef05c500 > [ 95.218903] Call Trace: > [ 95.218915] [] ? 0xf85e1fff > [ 95.218930] [] ? 0xf85dbfff > [ 95.218945] [] alloc_vmap_area.isra.16+0x1bd/0x2f0 > [ 95.218967] [] __get_vm_area_node.isra.17+0x8f/0x130 > [ 95.218988] [] __vmalloc_node_range+0x57/0x200 > [ 95.219009] [] ? lkma_test_init+0x45/0x70 [lkma_test] > [ 95.219031] [] __vmalloc_node+0x62/0x70 > [ 95.219049] [] ? lkma_test_init+0x45/0x70 [lkma_test] > [ 95.219071] [] vmalloc+0x38/0x40 > [ 95.219087] [] ? lkma_test_init+0x45/0x70 [lkma_test] > [ 95.219109] [] lkma_test_init+0x45/0x70 [lkma_test] > [ 95.219131] [] ? kzalloc+0x10/0x10 [lkma_test] > [ 95.219151] [] do_one_initcall+0x112/0x160 > [ 95.219171] [] ? set_section_ro_nx+0x54/0x59 > [ 95.219190] [] load_module+0x1d79/0x2660 > [ 95.219209] [] ? create_object+0x19d/0x280 > [ 95.219230] [] sys_init_module+0x78/0xb0 > [ 95.219250] [] sysenter_do_call+0x12/0x22 > [ 95.219268] Code: 39 03 73 0c 8b 3f 89 f0 83 c7 08 e9 3d ff ff ff 8b 46 f4 39 43 04 76 13 8b 3f 89 f0 83 c7 04 e9 29 ff ff ff e8 fb 1b 4a 00 eb ab<0f> 0b 8d 76 00 55 89 e5 56 53 66 66 66 66 90 83 60 0c df 89 c6 > [ 95.219415] EIP: [] __insert_vmap_area+0xfb/0x100 SS:ESP 0068:f027bd14 > [ 95.228313] ---[ end trace e0a1efb2acb97c98 ]--- > > A printk placed in __insert_vmap_area will show: > > [ 95.218256] va->va_start=0xfecfb000 tmp_va->va_end=0xf85e2000 va->va_end=0 tmp_va->va_start=0xf85dc000 > > and another one, before sum operation in alloc_vmap_area: > > [ 95.218204] addr = 0xfecfb000 size = 19943424 vend = 0xffbfe000 > > If after addition the result is smaller than one of the arguments, > then an overflow occurred. In our case there is an obvious overflow. > > Signed-off-by: Ghennadi Procopciuc > Cc: Daniel Baluta > > --- > Don't know if this is the right solution, but the bug happens for me in > 3.10-rc6 and 3.9. Hello Ghennadi, Could you please try the below patch to see if it is ok? The patch is based on today's linus' tree. ------------------------------------------------------ >From d513596c298cb90b6d4defa7a6e839ca2f9467c8 Mon Sep 17 00:00:00 2001 From: Zhang Yanfei Date: Fri, 21 Jun 2013 00:37:56 +0800 Subject: [PATCH] mm, vmalloc: Fix a potential overflow bug in alloc_vmap_area When searching a vmap area in the vmalloc space, we use (addr + size - 1) to check if the value is less than addr, which is an overflow. But we assign (addr + size) to vmap_area->va_end. So if we come across the below case: (addr + size - 1) : not overflow (addr + size) : overflow we will assign an overflow value (e.g 0) to vmap_area->va_end, And this will trigger BUG in __insert_vmap_area, causing system panic. So using (addr + size) to check the overflow should be the correct behaviour, not (addr + size - 1). Reported-by: Ghennadi Procopciuc Signed-off-by: Zhang Yanfei --- mm/vmalloc.c | 6 +++--- 1 files changed, 3 insertions(+), 3 deletions(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index d365724..d456560 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -388,12 +388,12 @@ nocache: addr = ALIGN(first->va_end, align); if (addr < vstart) goto nocache; - if (addr + size - 1 < addr) + if (addr + size < addr) goto overflow; } else { addr = ALIGN(vstart, align); - if (addr + size - 1 < addr) + if (addr + size < addr) goto overflow; n = vmap_area_root.rb_node; @@ -420,7 +420,7 @@ nocache: if (addr + cached_hole_size < first->va_start) cached_hole_size = first->va_start - addr; addr = ALIGN(first->va_end, align); - if (addr + size - 1 < addr) + if (addr + size < addr) goto overflow; if (list_is_last(&first->list, &vmap_area_list)) -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/