From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756378AbZFPWDg (ORCPT ); Tue, 16 Jun 2009 18:03:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753250AbZFPWD3 (ORCPT ); Tue, 16 Jun 2009 18:03:29 -0400 Received: from kroah.org ([198.145.64.141]:41742 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751666AbZFPWD2 (ORCPT ); Tue, 16 Jun 2009 18:03:28 -0400 Date: Tue, 16 Jun 2009 14:59:08 -0700 From: Greg KH To: Steven Noonan Cc: Michal Januszewski , Linux Kernel Mailing List Subject: Re: [BISECTED] uvesafb broken on 2.6.30 (v86d segfault) Message-ID: <20090616215908.GA4390@kroah.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.19 (2009-01-05) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 16, 2009 at 02:35:27PM -0700, Steven Noonan wrote: > I noticed that v86d segfaults on the final v2.6.30 release (breaking > uvesafb), but doesn't on the current master (v2.6.30-3392-g44b7532) > nor on v2.6.29.x. I originally tried to git-bisect v2.6.29 and > v2.6.30-rc1 (the first tag to contain the problem), but I ran into > multiple kernels that would either not compile or would simply panic > on boot. > > So instead, I did a 'git bisect' on commits between tags 'v2.6.30' and > commit-ish '44b7532' to find the commit that _corrected_ the problem > (reversing the 'good'/'bad' logic of git-bisect to do the task). > > First, here's the relevant dmesg output for broken kernels: > > [ 1.770858] general protection fault: 0000 [#1] SMP > [ 1.771080] last sysfs file: > [ 1.771163] Modules linked in: > [ 1.771287] > [ 1.771287] Pid: 531, comm: v86d Not tainted (2.6.30 #1) HP > Pavilion dv5000 (ES933AS#ABA) > [ 1.771287] EIP: 0060:[] EFLAGS: 00013286 CPU: 0 > [ 1.771287] EIP is at lockdep_sys_exit+0x7/0xa0 > [ 1.771287] EAX: 00000000 EBX: 00000000 ECX: 00000000 EDX: f73e0000 > [ 1.771287] ESI: c3d9e800 EDI: f73e1ed4 EBP: f73e1ec0 ESP: f73e1eac > [ 1.771287] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 > [ 1.771287] Process v86d (pid: 531, ti=f73e0000 task=f73fe9c0 > task.ti=f73e0000) > [ 1.771287] Stack: > [ 1.771287] f73e1f00 674c2f57 f73e1fb4 f73fe9c0 00000000 f73e0000 > c10334c4 f73e0000 > [ 1.771287] 00000000 00000000 00000000 00000000 00000000 00000000 > 00000000 00000000 > [ 1.771287] 00004f00 00000000 00000000 00000000 00000000 00000000 > 0000100a 0000c000 > [ 1.771287] Call Trace: > [ 1.771287] [] ? resume_userspace+0x8/0x28 > [ 1.771287] [] ? syscall_call+0x7/0xb > [ 1.771287] [] ? proc_taint+0xab/0x140 > [ 1.771287] Code: 04 24 00 4a b6 c1 e8 69 77 7e 00 85 f6 0f 8e 57 > ff ff ff eb a5 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90 90 55 89 e5 > 53 83 ec 10 <65> a1 14 00 00 00 89 45 f8 31 c0 64 8b 1d 20 20 ee c1 8b > 83 b0 > [ 1.771287] EIP: [] lockdep_sys_exit+0x7/0xa0 SS:ESP 0068:f73e1eac > [ 1.779083] ---[ end trace e93713a9d40cd06c ]--- > [ 6.777823] uvesafb: Getting VBE info block failed (eax=0x4f00, err=1) > [ 6.777924] uvesafb: vbe_init() failed with -22 > [ 6.778031] uvesafb: probe of uvesafb.0 failed with error -22 > > > > Michal (uvesafb creator) suggested that I try disabling lockdep to see > what happens. Doing so changes the dmesg output to this: > > [ 1.648494] general protection fault: 0000 [#1] SMP > [ 1.648695] last sysfs file: > [ 1.648771] Modules linked in: > [ 1.648903] > [ 1.648979] Pid: 529, comm: v86d Not tainted (2.6.30 #1) HP > Pavilion dv5000 (ES933AS#ABA) > [ 1.649086] EIP: 0060:[] EFLAGS: 00013082 CPU: 0 > [ 1.649176] EIP is at trace_hardirqs_off_caller+0xb/0x110 > [ 1.649261] EAX: c1033242 EBX: c1033242 ECX: 00000000 EDX: f684a000 > [ 1.649346] ESI: c2f54640 EDI: f684bed4 EBP: f684bebc ESP: f684be98 > [ 1.649381] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 > [ 1.649381] Process v86d (pid: 529, ti=f684a000 task=f7103ed0 > task.ti=f684a000) > [ 1.649381] Stack: > [ 1.649381] f684bed4 f684bec0 c1057457 f684bec0 f7103ed0 f684bf00 > 00000000 f684bfb4 > [ 1.649381] f7103ed0 f684a000 c148d5e4 f684a000 00000000 00000000 > c1033242 00000000 > [ 1.649381] 00000000 00000000 00000000 00000000 00000000 00004f00 > 00000000 00000000 > [ 1.649381] Call Trace: > [ 1.649381] [] ? do_sys_vm86+0x1b7/0x390 > [ 1.649381] [] ? trace_hardirqs_off_thunk+0xc/0x18 > [ 1.649381] [] ? resume_userspace+0x6/0x1c > [ 1.649381] [] ? syscall_call+0x7/0xb > [ 1.649381] [] ? do_sysctl+0x2db/0x3a0 > [ 1.649381] Code: c0 a3 f4 d1 de c1 31 c0 8b 55 fc 65 33 15 14 00 > 00 00 75 02 c9 c3 e8 05 8b f7 ff 90 8d 74 26 00 55 89 e5 83 ec 24 89 > 5d f4 89 c3 <65> a1 14 00 00 00 89 45 f0 31 c0 f6 05 f8 d1 de c1 02 89 > 75 f8 > [ 1.649381] EIP: [] trace_hardirqs_off_caller+0xb/0x110 > SS:ESP 0068:f684be98 > [ 1.649381] ---[ end trace e93713a9d40cd06c ]--- > [ 6.655118] uvesafb: Getting VBE info block failed (eax=0x4f00, err=1) > [ 6.655208] uvesafb: vbe_init() failed with -22 > [ 6.655299] uvesafb: probe of uvesafb.0 failed with error -22 > > > > Here's the bisection log (remember to mentally reverse 'bad' and 'good'): > > # bad: [45e3e1935e2857c54783291107d33323b3ef33c8] Merge branch > 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild-next > # good: [07a2039b8eb0af4ff464efd3dfd95de5c02648c6] Linux 2.6.30 > git bisect start 'HEAD' 'v2.6.30' > # bad: [8a1ca8cedd108c8e76a6ab34079d0bbb4f244799] Merge branch > 'perfcounters-for-linus' of > git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip > git bisect bad 8a1ca8cedd108c8e76a6ab34079d0bbb4f244799 > # bad: [6cd8e300b49332eb9eeda45816c711c198d31505] Merge branch > 'kvm-updates/2.6.31' of git://git.kernel.org/pub/scm/virt/kvm/kvm > git bisect bad 6cd8e300b49332eb9eeda45816c711c198d31505 > # bad: [73fbad283cfbbcf02939bdbda31fc4a30e729cca] Merge branch 'next' > into for-linus > git bisect bad 73fbad283cfbbcf02939bdbda31fc4a30e729cca > # good: [bb7762961d3ce745688e9050e914c1d3f980268d] Merge branch > 'x86-mm-for-linus' of > git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip > git bisect good bb7762961d3ce745688e9050e914c1d3f980268d > # bad: [75063600fd7b27fe447112c27997f100b9e2f99b] Merge branch > 'futexes-for-linus' of > git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip > git bisect bad 75063600fd7b27fe447112c27997f100b9e2f99b > # good: [6b2e8523df148c15ea5abf13075026fb8bdb3f86] xen: reserve Xen > start_info rather than e820 reserving > git bisect good 6b2e8523df148c15ea5abf13075026fb8bdb3f86 > # bad: [be15f9d63b97da0065187696962331de6cd9de9e] Merge branch > 'x86-xen-for-linus' of > git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip > git bisect bad be15f9d63b97da0065187696962331de6cd9de9e > # good: [bec706838ec2f9c8c2b99e88a1270d7cba159b06] Merge branch > 'x86-setup-for-linus' of > git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip > git bisect good bec706838ec2f9c8c2b99e88a1270d7cba159b06 > # bad: [0b8c3d5ab000c22889af7f9409799a6cdc31a2b2] x86: Clear TS in > irq_ts_save() when in an atomic section > git bisect bad 0b8c3d5ab000c22889af7f9409799a6cdc31a2b2 > # bad: [3aa6b186f86c5d06d6d92d14311ffed51f091f40] x86: Fix non-lazy GS > handling in sys_vm86() > git bisect bad 3aa6b186f86c5d06d6d92d14311ffed51f091f40 > # good: [4a4aca641bc4598e77b866804f47c651ec4a764d] x86: Add quirk for > reboot stalls on a Dell Optiplex 360 > git bisect good 4a4aca641bc4598e77b866804f47c651ec4a764d > > > > And here's the commit that fixes the problem: > > commit 3aa6b186f86c5d06d6d92d14311ffed51f091f40 > Author: Lubomir Rintel > Date: Sun Jun 7 16:23:48 2009 +0200 > > x86: Fix non-lazy GS handling in sys_vm86() > > This fixes a stack corruption panic or null dereference oops > due to a bad GS in resume_userspace() when returning from > sys_vm86() and calling lockdep_sys_exit(). > > Only a problem when CONFIG_LOCKDEP and CONFIG_CC_STACKPROTECTOR > enabled. > > Signed-off-by: Lubomir Rintel > Cc: H. Peter Anvin > LKML-Reference: <1244384628.2323.4.camel@bimbo> > Signed-off-by: Ingo Molnar > > > The cherry-pick of the bisected commit seems to work when applied to > vanilla v2.6.30. > > Greg, for v2.6.30.1, could you please cherry-pick commit > 3aa6b186f86c5d06d6d92d14311ffed51f091f40? I don't see that commit id in Linus's tree. Where did you get it from? thanks, greg k-h