Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756970Ab3G3KIp (ORCPT ); Tue, 30 Jul 2013 06:08:45 -0400 Received: from smtp4-g21.free.fr ([212.27.42.4]:33577 "EHLO smtp4-g21.free.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751822Ab3G3KIn convert rfc822-to-8bit (ORCPT ); Tue, 30 Jul 2013 06:08:43 -0400 Date: Tue, 30 Jul 2013 12:09:07 +0200 From: Jean-Francois Moine To: Dave Martin Cc: Robert Richter , Peter Zijlstra , Will Deacon , Jed Davis , "linux-kernel@vger.kernel.org" , Ingo Molnar , Paul Mackerras , Arnaldo Carvalho de Melo , Russell King , "oprofile-list@lists.sf.net" , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH] ARM: Fix r7/r11 confusion when CONFIG_THUMB2_KERNEL=y [OT] Message-ID: <20130730120907.6dcc469e@armhf> In-Reply-To: <20130730094457.GC2478@localhost.localdomain> References: <1373685501-1620-1-git-send-email-jld@mozilla.com> <20130715135420.GG10000@mudshark.cambridge.arm.com> <20130720044655.GC9433@mozilla.com> <20130721213753.GA29879@mudshark.cambridge.arm.com> <20130722185234.GA14519@localhost.localdomain> <20130729212140.GB12681@mozilla.com> <20130730092517.GB2478@localhost.localdomain> <20130730113853.46cbb00a@armhf> <20130730094457.GC2478@localhost.localdomain> X-Mailer: Claws Mail 3.9.2 (GTK+ 2.24.20; arm-unknown-linux-gnueabihf) Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6393 Lines: 111 On Tue, 30 Jul 2013 10:44:57 +0100 Dave Martin wrote: > On Tue, Jul 30, 2013 at 11:38:53AM +0200, Jean-Francois Moine wrote: > > On Tue, 30 Jul 2013 10:25:18 +0100 > > Dave Martin wrote: > > > > > The pragmatic route is less contraversial and lower overhead: even though > > > it's not correct as per the ABI, GCC is the only supported compiler for > > > building the kernel anyway. > > > > BTW, kernels compiled with gcc-4.8 don't work. > > I haven't tried 4.8 yet. Do you know what the problem is? I randomly get 'NULL pointer dereference' in ext3 (trace below). I compared the gcc-4.6 and gcc-4.8 ARM codes of the function where the problem occurs, and, while the gcc-4.8 code seems a bit odd, the problem should be somewhere else, surely in the memory management. > > Did anybody succeed with clang? > > Hmm, I've no idea. Is this possible? freebsd kernels are compiled with clang, and I heard about linux patches, but I did not find them yet. Otherwise, replacing gcc with clang in the main kernel Makefile stops on an assembly instruction where odd register numbers could not be used. I did not go further. ------------------ gcc-4.8.1 kernel oops ---------------- Unable to handle kernel NULL pointer dereference at virtual address 00000003 pgd = bcf74000 [00000003] *pgd=3cf16831, *pte=00000000, *ppte=00000000 Internal error: Oops: 811 [#1] PREEMPT ARM Modules linked in: arc4 p54usb p54common crc_ccitt mac80211 cfg80211 fbcon bitblit softcursor font snd_soc_spdif_tx tda998x dove_drm drm_kms_helper snd_soc_kirkwood mv_cesa drm snd_soc_kirkwood_spdif CPU: 0 PID: 2426 Comm: iceweasel Not tainted 3.10.0-dirty #55 task: bd92b700 ti: bcf48000 task.ti: bcf48000 PC is at do_mpage_readpage+0x754/0x888 LR is at bio_add_page+0x44/0x4c pc : [<800e3c70>] lr : [<800db8ac>] psr: 600f0113 sp : bcf49c34 ip : bcf49c88 fp : bcf49c5c r10: 00000003 r9 : 00000000 r8 : 00000043 r7 : 00000001 r6 : 800e3f54 r5 : bcf49c30 r4 : 00000003 r3 : 00020000 r2 : 00000042 r1 : 00000000 r0 : bcf49c5c Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user Control: 10c5387d Table: 3cf74019 DAC: 00000015 Process iceweasel (pid: 2426, stack limit = 0xbcf48240) Stack: (0xbcf49c34 to 0xbcf4a000) 9c20: 00000020 bcf49d24 00200200 9c40: 00100100 bd580d94 00000000 80de4260 bcf49cf4 bcf49c60 800e3e78 800e3528 9c60: bcf49c88 bcf49c7c 801164cc 000000c1 804d660c 801164cc da0716b4 00000042 9c80: 00000000 00000000 00000020 00000000 80de4260 000000c1 00287ab6 00000000 9ca0: 00020000 80073500 bd402c80 804d6670 00100100 00000002 00200200 8039a2ac 9cc0: 804d660c 00000002 804d6ca0 80113f84 00000020 00000020 00000042 000000b4 9ce0: 00000000 00000020 bcf49d04 bcf49cf8 80113fa8 800e3db0 bcf49d6c bcf49d08 9d00: 80079ef4 80113f90 bcf00c00 00000018 bd580d94 00000020 bd580d98 bcf49d24 9d20: 00000001 80de4394 80de4254 91827364 bcf49d30 bcf49d30 bcf49d38 bcf49d38 9d40: 00000052 00000052 bcf00c00 bd580d94 bd580d94 bcf49df0 00000000 bcf6c0d0 9d60: bcf49d84 bcf49d70 8007a600 80079d10 00000008 7319d000 bcf49ddc bcf49d88 9d80: 800719f4 8007a5dc 80076670 80075448 00000001 000000c1 bcf00c48 00000002 9da0: 3c5e818f 00000000 bcf48008 bd580ce0 80013e40 bcf6c0d0 bdbc2e40 00000000 9dc0: 7319d000 00000028 00000000 bcf75cc0 bcf49e2c bcf49de0 8008b0ac 8007163c 9de0: bdb247a8 00000000 00000000 00000200 00000028 00000052 7319d000 00000000 9e00: 8007b8d0 bcf6c0d0 7319d000 7319d000 bdbc2e40 bcf6c0d0 00000028 00000000 9e20: bcf49e7c bcf49e30 8008e584 8008b048 00000052 00000028 00000000 000000b1 9e40: da538506 000000b1 804bb718 00000004 804bb708 bcf74000 00000398 7319d000 9e60: bdbc2e40 bcf6c0d0 00000028 bcf75cc0 bcf49eb4 bcf49e80 8008ed14 8008e51c 9e80: bcf75cc0 00000028 da538506 00000017 bcf49fb0 bdbc2e40 bd92b700 7319d288 9ea0: bcf48038 00000028 bcf49efc bcf49eb8 80013c38 8008ec80 0000b533 00000000 9ec0: 0000b533 00000200 00000000 bdbc2e78 00000000 00000017 80013a64 804b76f4 9ee0: 7319d288 bcf49fb0 00000ea1 00000000 bcf49fac bcf49f00 80008460 80013a70 9f00: bcf00c00 00000001 000b45c0 804bc488 bcf48000 00000000 0000001d 00000000 9f20: 00000001 73098000 bcf49f54 804bc488 bcf49f54 bcf49f40 8006a284 8006b524 9f40: 804bb900 bcf48028 00000000 00000000 0000001d 00000000 bcf49f7c bcf49f68 9f60: 80022424 8006db18 00020000 804c3c90 bcf49f9c bcf49f80 8000ec2c 800223a4 9f80: 00000621 75253ff0 200f0030 75238ed2 200f0030 ffffffff 00000000 00000ea1 9fa0: 00000000 bcf49fb0 8000e118 8000842c 7319d2ec 7319d292 7ee06c98 7319d288 9fc0: 7ee06c98 73098000 00000000 00000000 00000ea1 00000ea1 00000000 73223be0 9fe0: 752811fc 7ee06b88 7523bd75 75238ed2 200f0030 ffffffff 00000000 00000000 Backtrace: [<800e351c>] (do_mpage_readpage+0x0/0x888) from [<800e3e78>] (mpage_readpages+0xd4/0x130) [<800e3da4>] (mpage_readpages+0x0/0x130) from [<80113fa8>] (ext3_readpages+0x24/0x28) [<80113f84>] (ext3_readpages+0x0/0x28) from [<80079ef4>] (__do_page_cache_readahead+0x1f0/0x2d8) [<80079d04>] (__do_page_cache_readahead+0x0/0x2d8) from [<8007a600>] (ra_submit+0x30/0x38) [<8007a5d0>] (ra_submit+0x0/0x38) from [<800719f4>] (filemap_fault+0x3c4/0x4b0) [<80071630>] (filemap_fault+0x0/0x4b0) from [<8008b0ac>] (__do_fault+0x70/0x4a8) [<8008b03c>] (__do_fault+0x0/0x4a8) from [<8008e584>] (handle_pte_fault+0x74/0x764) [<8008e510>] (handle_pte_fault+0x0/0x764) from [<8008ed14>] (handle_mm_fault+0xa0/0xd4) [<8008ec74>] (handle_mm_fault+0x0/0xd4) from [<80013c38>] (do_page_fault+0x1d4/0x278) [<80013a64>] (do_page_fault+0x0/0x278) from [<80008460>] (do_DataAbort+0x40/0xa0) [<80008420>] (do_DataAbort+0x0/0xa0) from [<8000e118>] (__dabt_usr+0x38/0x40) Exception stack(0xbcf49fb0 to 0xbcf49ff8) 9fa0: 7319d2ec 7319d292 7ee06c98 7319d288 9fc0: 7ee06c98 73098000 00000000 00000000 00000ea1 00000ea1 00000000 73223be0 9fe0: 752811fc 7ee06b88 7523bd75 75238ed2 200f0030 ffffffff r8:00000ea1 r7:00000000 r6:ffffffff r5:200f0030 r4:75238ed2 Code: e0854184 e51b0084 e14424d8 e51b40a0 (e1c420f0) ---[ end trace 838796f906351fb0 ]--- -- Ken ar c'hentañ | ** Breizh ha Linux atav! ** Jef | http://moinejf.free.fr/ -- 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/