Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759439AbXHKRAw (ORCPT ); Sat, 11 Aug 2007 13:00:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753667AbXHKRAp (ORCPT ); Sat, 11 Aug 2007 13:00:45 -0400 Received: from smtp2.linux-foundation.org ([207.189.120.14]:36484 "EHLO smtp2.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753077AbXHKRAo (ORCPT ); Sat, 11 Aug 2007 13:00:44 -0400 Date: Sat, 11 Aug 2007 10:00:15 -0700 From: Andrew Morton To: "Balbir Singh" Cc: linux-kernel , WU Fengguang Subject: Re: [BUGFIX] NULL pointer dereference in __vm_enough_memory() Message-Id: <20070811100015.2417788e.akpm@linux-foundation.org> In-Reply-To: <661de9470708110730r1267bdfdp1e76546e11b64f78@mail.gmail.com> References: <386838491.27058@ustc.edu.cn> <661de9470708110730r1267bdfdp1e76546e11b64f78@mail.gmail.com> X-Mailer: Sylpheed 2.4.1 (GTK+ 2.8.17; x86_64-unknown-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4309 Lines: 91 On Sat, 11 Aug 2007 20:00:12 +0530 "Balbir Singh" wrote: > On 8/11/07, Fengguang Wu wrote: hm, both people who replied to this removed Fengguang from cc. Disagreement between headers and MUAs, perhaps? > > Andrew, > > > > I'm not sure if this patch is the right fix for the bug. But it do > > stops the oops message. The bug also happens in 2.6.23-rc1-mm2/2.6.23-rc2-mm2. > > I'm running debian/sid. The .config is attached. > > > > > > Unable to handle kernel NULL pointer dereference at 0000000000000138 RIP > > [] __vm_enough_memory+0x76/0x120 > > PGD 7cd84067 PUD 7d9c3067 PMD 0 > > Oops: 0000 [2] SMP > > CPU 1 > > Modules linked in: eeprom lm85 hwmon_vid i2c_core tun fuse kvm snd_hda_intel snd_pcm_oss snd_mixer_oss snd_pcm snd_timer sg snd soundcore sr_mod cdrom snd_page_alloc pcspkr evdev button raid0 usbhid sd_mod uhci_hcd ehci_hcd ata_piix ahci ohci1394 ieee1394 thermal processor fan > > Pid: 4305, comm: khelper Tainted: G D 2.6.23-rc2 #9 > > RIP: 0010:[] [] __vm_enough_memory+0x76/0x120 > > RSP: 0000:ffff81007a3d1d30 EFLAGS: 00010206 > > RAX: 0000000000000000 RBX: 0000000000000001 RCX: 000000000003e142 > > RDX: 00000000000004f4 RSI: 0000000000000001 RDI: 0000000000000001 > > RBP: ffff81007a3d1d40 R08: ffff81007a3d1d78 R09: 0000000000000000 > > R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 > > R13: 0000000000000000 R14: ffff81007d0c0188 R15: ffff81007d577b18 > > FS: 0000000000000000(0000) GS:ffff81007efa11d0(0000) knlGS:0000000000000000 > > CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b > > CR2: 0000000000000138 CR3: 000000003799b000 CR4: 00000000000006e0 > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 > > Process khelper (pid: 4305, threadinfo ffff81007a3d0000, task ffff81007a30acc0) > > Stack: 0000000000000001 ffff81007d577b18 ffff81007a3d1d60 ffffffff811297ff > > 0000000000000001 ffff810037c84bb8 ffff81007a3d1da0 ffffffff81092532 > > ffff81007d0c0188 0000000000000000 ffff81007d577b20 0000000000000000 > > Call Trace: > > [] cap_vm_enough_memory+0x2f/0x40 > > [] insert_vm_struct+0xa2/0xb0 > > [] bprm_mm_init+0x11e/0x1b0 > > [] do_execve+0x81/0x220 > > [] __call_usermodehelper+0x0/0x90 > > [] sys_execve+0x46/0xb0 > > [] __call_usermodehelper+0x0/0x90 > > [] kernel_execve+0x64/0xd0 > > [] __call_usermodehelper+0x0/0x90 > > [] ____call_usermodehelper+0x174/0x190 > > [] child_rip+0xa/0x12 > > [] schedule_tail+0x78/0x100 > > [] restore_args+0x0/0x30 > > [] ____call_usermodehelper+0x0/0x190 > > [] child_rip+0x0/0x12 > > > > > > Code: 48 8b 80 38 01 00 00 48 c1 e8 05 48 29 c1 48 39 ca 0f 8c 89 > > RIP [] __vm_enough_memory+0x76/0x120 > > RSP > > CR2: 0000000000000138 > > > > Signed-off-by: Fengguang Wu > > --- > > mm/mmap.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > --- linux-2.6.23-rc2-mm2.orig/mm/mmap.c > > +++ linux-2.6.23-rc2-mm2/mm/mmap.c > > @@ -166,7 +166,8 @@ int __vm_enough_memory(long pages, int c > > > > /* Don't let a single process grow too big: > > leave 3% of the size of this process for other processes */ > > - allowed -= current->mm->total_vm / 32; > > + if (current->mm) > > + allowed -= current->mm->total_vm / 32; > > > > /* > > * cast `allowed' as a signed long because vm_committed_space > > > > > > Shouldn't we just not stop vm accounting for kernel threads? > Could be. It'd help heaps if we knew which patch in -mm caused this, but from a quick peek it seems to me that mainline should be vulnerable as well. - 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/