Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752789Ab3E3MAy (ORCPT ); Thu, 30 May 2013 08:00:54 -0400 Received: from co202.xi-lite.net ([149.6.83.202]:47752 "EHLO co202.xi-lite.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751588Ab3E3MAo (ORCPT ); Thu, 30 May 2013 08:00:44 -0400 Message-ID: <51A73F68.7060500@parrot.com> Date: Thu, 30 May 2013 14:00:40 +0200 From: Matthieu CASTET User-Agent: Thunderbird 2.0.0.24 (X11/20100228) MIME-Version: 1.0 To: linux-arm-kernel , "linux-kernel@vger.kernel.org" , "Wang, Yalin" Subject: Re : A bug about system call on ARM Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2571 Lines: 83 Hello, > Hi all, > > I am a new comer to this mailing list , > I am happy to join this community . > You should send this to arm ML. Also I believe most of people don't enable CONFIG_OABI_COMPAT, that's why they don't hit the bug. Matthieu > I have a bug reported from our android phones which is caused by the system call . > It seems like kernel bugs from my view . > > Crash in file arch\arm\kernel\ entry-common.S > > /***************************************************************/ > > ENTRY(vector_swi) > sub sp, sp, #S_FRAME_SIZE > stmia sp, {r0 - r12} @ Calling r0 - r12 > ARM( add r8, sp, #S_PC ) > ARM( stmdb r8, {sp, lr}^ ) @ Calling sp, lr > THUMB( mov r8, sp ) > THUMB( store_user_sp_lr r8, r10, S_SP ) @ calling sp, lr > mrs r8, spsr @ called from non-FIQ mode, so ok. > str lr, [sp, #S_PC] @ Save calling PC > str r8, [sp, #S_PSR] @ Save CPSR > str r0, [sp, #S_OLD_R0] @ Save OLD_R0 > zero_fp > > /* > * Get the system call number. > */ > > #if defined(CONFIG_OABI_COMPAT) > > /* > * If we have CONFIG_OABI_COMPAT then we need to look at the swi > * value to determine if it is an EABI or an old ABI call. > */ > #ifdef CONFIG_ARM_THUMB > tst r8, #PSR_T_BIT > movne r10, #0 @ no thumb OABI emulation > ldreq r10, [lr, #-4] @ get SWI instruction // crash at this instruction, \ > when get SWI instruction #else > ldr r10, [lr, #-4] @ get SWI instruction > A710( and ip, r10, #0x0f000000 @ check for SWI ) > A710( teq ip, #0x0f000000 ) > A710( bne .Larm710bug ) > #endif > #ifdef CONFIG_CPU_ENDIAN_BE8 > rev r10, r10 @ little endian instruction > #endif > > /************************************************************************************* \ > **************/ > > Then reason why it will crash when get SWI instruction is maybe > This page is clear to aged by kernel, > But this MMU fault happpened in kernel, > So the kernel do_page_fault function will not clear this page to young, > So that will crash . > > It should poll this page to make it present or the fault should be handled by fixup \ > section , Anyway, this place should not crash by kernel . > > The kernel version I used is 3.4.0 > I have add the kernel log and the call stack recovered by trace32 tools > Pls have a look at it . > > -- 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/