Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932126AbZJLMXf (ORCPT ); Mon, 12 Oct 2009 08:23:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755391AbZJLMXe (ORCPT ); Mon, 12 Oct 2009 08:23:34 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:51363 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753943AbZJLMXd (ORCPT ); Mon, 12 Oct 2009 08:23:33 -0400 Date: Mon, 12 Oct 2009 14:22:45 +0200 From: Ingo Molnar To: Alan Cox Cc: Linus Torvalds , Greg KH , Linux Kernel Mailing List Subject: Re: [crash] NULL pointer dereference at IP: [] uart_close+0x2a/0x1e4 Message-ID: <20091012122245.GA22088@elte.hu> References: <20091012080511.GA22607@elte.hu> <20091012091954.GA31171@elte.hu> <20091012092713.GA32647@elte.hu> <20091012112504.GA10002@elte.hu> <20091012124501.3c1ac94f@lxorguk.ukuu.org.uk> <20091012115549.GA13987@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20091012115549.GA13987@elte.hu> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.5 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3295 Lines: 70 * Ingo Molnar wrote: > > so uart_close takes the wrong lock. I've checked the rest of the > > patch for the same error and I don't see any other screwups. > > Cool! This very much looks like something that could fix both problems. > I've started testing your fix. Unfortunately it does not solve the problem, i still get: BUG: unable to handle kernel NULL pointer dereference at 0000000000000240 IP: [] uart_close+0x24/0x1e5 PGD 77166067 PUD 77171067 PMD 0 Oops: 0000 [#1] DEBUG_PAGEALLOC last sysfs file: CPU 0 Modules linked in: Pid: 1107, comm: hwclock Not tainted 2.6.32-rc4-tip #8185 System Product Name RIP: 0010:[] [] uart_close+0x24/0x1e5 RSP: 0018:ffff8800770e9b98 EFLAGS: 00010246 RAX: ffffffff812ea1f1 RBX: ffff88007df80000 RCX: 0000000000000000 RDX: ffff88007aaa7900 RSI: ffff88007df80000 RDI: ffff88007b3eb000 RBP: ffff8800770e9bb8 R08: ffff88007a62cd80 R09: ffff88007a62c600 R10: 0000000000000246 R11: ffffffff812c1ed9 R12: 0000000000000000 R13: ffff88007b3eb000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007fc1bae596f0(0000) GS:ffffffff81b38000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000000000000240 CR3: 0000000077187000 CR4: 00000000000026f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process hwclock (pid: 1107, threadinfo ffff8800770e8000, task ffff88007a62c600) Stack: ffff88007b3eb000 0000000000000000 00000000fffffffa 0000000000000000 <0> ffff8800770e9c98 ffffffff812c3ece ffff8800770e9bf8 0000000000000246 <0> ffff88007aab8150 ffff88007aab8000 ffff88007b3eb000 ffffffff81d57560 Call Trace: [] tty_release_dev+0x1ca/0x4d8 [] ? mutex_unlock+0xe/0x10 [] ? _spin_unlock+0x2b/0x2f [] tty_open+0x33f/0x41d [] chrdev_open+0x179/0x19a [] __dentry_open+0x1cf/0x2f9 [] ? chrdev_open+0x0/0x19a [] nameidata_to_filp+0x45/0x56 [] do_filp_open+0x58a/0xa39 [] ? native_sched_clock+0x3b/0x52 [] ? sched_clock+0x17/0x1b [] ? cpu_clock+0x41/0x5b [] ? alloc_fd+0x110/0x11f [] ? _spin_unlock+0x2b/0x2f [] ? alloc_fd+0x110/0x11f [] do_sys_open+0x62/0x109 [] sys_open+0x20/0x22 [] system_call_fastpath+0x16/0x1b Code: 5d 41 5e 41 5f c9 c3 55 48 89 e5 41 56 41 55 41 54 53 0f 1f 44 00 00 f6 05 53 29 55 01 08 4c 8b a7 28 04 00 00 49 89 fd 48 89 f3 <4d> 8b b4 24 40 02 00 00 74 16 f6 05 3c 29 55 01 40 74 0d 80 3d RIP [] uart_close+0x24/0x1e5 RSP CR2: 0000000000000240 ---[ end trace a06c2589766a51bf ]--- I still think it's a break-through - you found one bug in the patch already, which means that there could be more in there ;-) Ingo -- 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/