Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751407AbWCBGhO (ORCPT ); Thu, 2 Mar 2006 01:37:14 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751408AbWCBGhO (ORCPT ); Thu, 2 Mar 2006 01:37:14 -0500 Received: from fmr18.intel.com ([134.134.136.17]:27552 "EHLO orsfmr003.jf.intel.com") by vger.kernel.org with ESMTP id S1751407AbWCBGhM convert rfc822-to-8bit (ORCPT ); Thu, 2 Mar 2006 01:37:12 -0500 X-MimeOLE: Produced By Microsoft Exchange V6.5.7226.0 Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="gb2312" Content-Transfer-Encoding: 8BIT Subject: RE: [PATCH]kprobe handler discard user space trap Date: Thu, 2 Mar 2006 14:36:56 +0800 Message-ID: <117E3EB5059E4E48ADFF2822933287A441C7DC@pdsmsx404> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: [PATCH]kprobe handler discard user space trap Thread-Index: AcY8+egvVtNDijP0T5G4g4vNxfXCwwAyL17Q From: "Zhang, Yanmin" To: "bibo mao" , Cc: "Mao, Bibo" , "Andrew Morton" , , "Ananth N Mavinakayanahalli" , "Keshavamurthy, Anil S" , X-OriginalArrivalTime: 02 Mar 2006 06:36:57.0964 (UTC) FILETIME=[B44F22C0:01C63DC3] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5907 Lines: 139 >>-----Original Message----- >>From: linux-kernel-owner@vger.kernel.org [mailto:linux-kernel-owner@vger.kernel.org] On Behalf Of bibo mao >>Sent: 2006??3??1?? 14:23 >>To: prasanna@in.ibm.com >>Cc: Mao, Bibo; Andrew Morton; linux-kernel@vger.kernel.org; Ananth N Mavinakayanahalli; Keshavamurthy, Anil S; >>hiramatu@sdl.hitachi.co.jp >>Subject: Re: [PATCH]kprobe handler discard user space trap >> >>This patch removes code in kprobe_handler() function which calculates >>user space int3 trap address in i386 architecture. And this patch is >>based on kprobe-handler-discard-user-space-trap.patch, against >>2.6.16-rc5-mm1. >> >>Signed-off-by: bibo mao >> >>--- a/arch/i386/kernel/kprobes.c 2006-03-01 12:48:54.000000000 +0800 >>+++ b/arch/i386/kernel/kprobes.c 2006-03-01 14:08:12.000000000 +0800 >>@@ -203,7 +203,7 @@ static int __kprobes kprobe_handler(stru >> { >> struct kprobe *p; >> int ret = 0; >>- kprobe_opcode_t *addr = NULL; >>+ kprobe_opcode_t *addr = (kprobe_opcode_t *)(regs->eip - >>sizeof(kprobe_opcode_t)); >> unsigned long *lp; >> struct kprobe_ctlblk *kcb; >> #ifdef CONFIG_PREEMPT >>@@ -217,17 +217,6 @@ static int __kprobes kprobe_handler(stru >> preempt_disable(); >> kcb = get_kprobe_ctlblk(); >> >>- /* Check if the application is using LDT entry for its code segment and >>- * calculate the address by reading the base address from the LDT entry. >>- */ >>- if ((regs->xcs & 4) && (current->mm)) { >>- lp = (unsigned long *) ((unsigned long)((regs->xcs >> 3) * 8) >>- + (char *) current->mm->context.ldt); >>- addr = (kprobe_opcode_t *) (get_desc_base(lp) + regs->eip - >>- sizeof(kprobe_opcode_t)); >>- } else { >>- addr = (kprobe_opcode_t *)(regs->eip - sizeof(kprobe_opcode_t)); >>- } >> /* Check we're not actually recursing */ >> if (kprobe_running()) { >> p = get_kprobe(addr); >> >>Prasanna S Panchamukhi wrote: >>> On Tue, Feb 28, 2006 at 03:23:12PM +0800, bibo,mao wrote: >>>> Currently kprobe handler traps only happen in kernel space, so function >>>> kprobe_exceptions_notify should skip traps which happen in user space. >>>> This patch modifies this, and it is based on 2.6.16-rc4. >>> >>> You need to remove the code which calculates the >>> user space address in kprobe_handler() and also you need >>> to remove the code that checks for VM86 in i386, since >>> your patch check if user/vm86 at the top level. >>> >>> Thanks >>> Prasanna >>> >>>> Signed-off-by: bibo mao >>>> >>>> diff -Nruap a/arch/i386/kernel/kprobes.c b/arch/i386/kernel/kprobes.c >>>> --- a/arch/i386/kernel/kprobes.c 2006-02-25 17:08:52.000000000 +0800 >>>> +++ b/arch/i386/kernel/kprobes.c 2006-03-01 10:37:50.000000000 +0800 >>>> @@ -463,6 +463,9 @@ int __kprobes kprobe_exceptions_notify(s >>>> struct die_args *args = (struct die_args *)data; >>>> int ret = NOTIFY_DONE; >>>> >>>> + if (user_mode(args->regs)) >>>> + return ret; >>>> + >>>> switch (val) { >>>> case DIE_INT3: >>>> if (kprobe_handler(args->regs)) >>>> diff -Nruap a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c >>>> --- a/arch/ia64/kernel/kprobes.c 2006-02-25 17:08:53.000000000 +0800 >>>> +++ b/arch/ia64/kernel/kprobes.c 2006-03-01 10:39:15.000000000 +0800 >>>> @@ -740,6 +740,9 @@ int __kprobes kprobe_exceptions_notify(s >>>> struct die_args *args = (struct die_args *)data; >>>> int ret = NOTIFY_DONE; >>>> >>>> + if (user_mode(args->regs)) >>>> + return ret; >>>> + >>>> switch(val) { >>>> case DIE_BREAK: >>>> /* err is break number from ia64_bad_break() */ >>>> diff -Nruap a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c >>>> --- a/arch/powerpc/kernel/kprobes.c 2006-02-25 17:08:52.000000000 +0800 >>>> +++ b/arch/powerpc/kernel/kprobes.c 2006-03-01 10:39:53.000000000 +0800 >>>> @@ -397,6 +397,9 @@ int __kprobes kprobe_exceptions_notify(s >>>> struct die_args *args = (struct die_args *)data; >>>> int ret = NOTIFY_DONE; >>>> >>>> + if (user_mode(args->regs)) >>>> + return ret; >>>> + >>>> switch (val) { >>>> case DIE_BPT: >>>> if (kprobe_handler(args->regs)) >>>> diff -Nruap a/arch/sparc64/kernel/kprobes.c b/arch/sparc64/kernel/kprobes.c >>>> --- a/arch/sparc64/kernel/kprobes.c 2006-02-25 17:08:52.000000000 +0800 >>>> +++ b/arch/sparc64/kernel/kprobes.c 2006-03-01 10:40:16.000000000 +0800 >>>> @@ -324,6 +324,9 @@ int __kprobes kprobe_exceptions_notify(s >>>> struct die_args *args = (struct die_args *)data; >>>> int ret = NOTIFY_DONE; >>>> >>>> + if (user_mode(args->regs)) >>>> + return ret; >>>> + >>>> switch (val) { >>>> case DIE_DEBUG: >>>> if (kprobe_handler(args->regs)) >>>> diff -Nruap a/arch/x86_64/kernel/kprobes.c b/arch/x86_64/kernel/kprobes.c >>>> --- a/arch/x86_64/kernel/kprobes.c 2006-02-25 17:08:52.000000000 +0800 >>>> +++ b/arch/x86_64/kernel/kprobes.c 2006-03-01 10:38:48.000000000 +0800 >>>> @@ -601,6 +601,9 @@ int __kprobes kprobe_exceptions_notify(s >>>> struct die_args *args = (struct die_args *)data; >>>> int ret = NOTIFY_DONE; >>>> >>>> + if (user_mode(args->regs)) >>>> + return ret; >>>> + >>>> switch (val) { >>>> case DIE_INT3: >>>> if (kprobe_handler(args->regs)) >>> When my ia64 box reboots with kernel 2.6.16-rc5-mm1, kernel hanged in kprobe_exceptions_notify. args->regs doesn't always point to a valid address. It might be NULL. machine_restart calls notify_die with parameter regs=NULL. Pls. check args->regs before using user_mode. Pls. also check if other archs have the same problem. - 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/