Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932842AbXIUWoP (ORCPT ); Fri, 21 Sep 2007 18:44:15 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1764047AbXIUWck (ORCPT ); Fri, 21 Sep 2007 18:32:40 -0400 Received: from ns.suse.de ([195.135.220.2]:57073 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1763594AbXIUWcc (ORCPT ); Fri, 21 Sep 2007 18:32:32 -0400 From: Andi Kleen References: <200709221231.836138000@suse.de> In-Reply-To: <200709221231.836138000@suse.de> To: jbeulich@novell.com, patches@x86-64.org, linux-kernel@vger.kernel.org Subject: [PATCH] [31/50] x86_64: honor notify_die() returning NOTIFY_STOP Message-Id: <20070921223230.D0C8013DCD@wotan.suse.de> Date: Sat, 22 Sep 2007 00:32:30 +0200 (CEST) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5335 Lines: 162 From: "Jan Beulich" If a debugger or other low level code resolves a kernel exception, don't send signals, kill the kernel, or do anything the like. Signed-off-by: Jan Beulich Signed-off-by: Andi Kleen arch/x86_64/kernel/mce.c | 7 ++++--- arch/x86_64/kernel/traps.c | 23 +++++++++++++++-------- arch/x86_64/mm/fault.c | 12 ++++++------ include/asm-x86_64/kdebug.h | 4 ++-- 4 files changed, 27 insertions(+), 19 deletions(-) Index: linux/arch/x86_64/kernel/mce.c =================================================================== --- linux.orig/arch/x86_64/kernel/mce.c +++ linux/arch/x86_64/kernel/mce.c @@ -196,9 +196,10 @@ void do_machine_check(struct pt_regs * r atomic_inc(&mce_entry); - if (regs) - notify_die(DIE_NMI, "machine check", regs, error_code, 18, SIGKILL); - if (!banks) + if ((regs + && notify_die(DIE_NMI, "machine check", regs, error_code, + 18, SIGKILL) == NOTIFY_STOP) + || !banks) goto out2; memset(&m, 0, sizeof(struct mce)); Index: linux/arch/x86_64/kernel/traps.c =================================================================== --- linux.orig/arch/x86_64/kernel/traps.c +++ linux/arch/x86_64/kernel/traps.c @@ -557,7 +557,7 @@ unsigned __kprobes long oops_begin(void) return flags; } -void __kprobes oops_end(unsigned long flags) +void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr) { die_owner = -1; bust_spinlocks(0); @@ -568,12 +568,17 @@ void __kprobes oops_end(unsigned long fl else /* Nest count reaches zero, release the lock. */ spin_unlock_irqrestore(&die_lock, flags); + if (!regs) { + oops_exit(); + return; + } if (panic_on_oops) panic("Fatal exception"); oops_exit(); + do_exit(signr); } -void __kprobes __die(const char * str, struct pt_regs * regs, long err) +int __kprobes __die(const char * str, struct pt_regs * regs, long err) { static int die_counter; printk(KERN_EMERG "%s: %04lx [%u] ", str, err & 0xffff,++die_counter); @@ -587,7 +592,8 @@ void __kprobes __die(const char * str, s printk("DEBUG_PAGEALLOC"); #endif printk("\n"); - notify_die(DIE_OOPS, str, regs, err, current->thread.trap_no, SIGSEGV); + if (notify_die(DIE_OOPS, str, regs, err, current->thread.trap_no, SIGSEGV) == NOTIFY_STOP) + return 1; show_registers(regs); add_taint(TAINT_DIE); /* Executive summary in case the oops scrolled away */ @@ -596,6 +602,7 @@ void __kprobes __die(const char * str, s printk(" RSP <%016lx>\n", regs->rsp); if (kexec_should_crash(current)) crash_kexec(regs); + return 0; } void die(const char * str, struct pt_regs * regs, long err) @@ -605,9 +612,9 @@ void die(const char * str, struct pt_reg if (!user_mode(regs)) report_bug(regs->rip, regs); - __die(str, regs, err); - oops_end(flags); - do_exit(SIGSEGV); + if (__die(str, regs, err)) + regs = NULL; + oops_end(flags, regs, SIGSEGV); } void __kprobes die_nmi(char *str, struct pt_regs *regs, int do_panic) @@ -624,10 +631,10 @@ void __kprobes die_nmi(char *str, struct crash_kexec(regs); if (do_panic || panic_on_oops) panic("Non maskable interrupt"); - oops_end(flags); + oops_end(flags, NULL, SIGBUS); nmi_exit(); local_irq_enable(); - do_exit(SIGSEGV); + do_exit(SIGBUS); } static void __kprobes do_trap(int trapnr, int signr, char *str, Index: linux/arch/x86_64/mm/fault.c =================================================================== --- linux.orig/arch/x86_64/mm/fault.c +++ linux/arch/x86_64/mm/fault.c @@ -234,9 +234,9 @@ static noinline void pgtable_bad(unsigne tsk->thread.cr2 = address; tsk->thread.trap_no = 14; tsk->thread.error_code = error_code; - __die("Bad pagetable", regs, error_code); - oops_end(flags); - do_exit(SIGKILL); + if (__die("Bad pagetable", regs, error_code)) + regs = NULL; + oops_end(flags, regs, SIGKILL); } /* @@ -541,11 +541,11 @@ no_context: tsk->thread.cr2 = address; tsk->thread.trap_no = 14; tsk->thread.error_code = error_code; - __die("Oops", regs, error_code); + if (__die("Oops", regs, error_code)) + regs = NULL; /* Executive summary in case the body of the oops scrolled away */ printk(KERN_EMERG "CR2: %016lx\n", address); - oops_end(flags); - do_exit(SIGKILL); + oops_end(flags, regs, SIGKILL); /* * We ran out of memory, or some other thing happened to us that made Index: linux/include/asm-x86_64/kdebug.h =================================================================== --- linux.orig/include/asm-x86_64/kdebug.h +++ linux/include/asm-x86_64/kdebug.h @@ -27,10 +27,10 @@ enum die_val { extern void printk_address(unsigned long address); extern void die(const char *,struct pt_regs *,long); -extern void __die(const char *,struct pt_regs *,long); +extern int __must_check __die(const char *, struct pt_regs *, long); extern void show_registers(struct pt_regs *regs); extern void dump_pagetable(unsigned long); extern unsigned long oops_begin(void); -extern void oops_end(unsigned long); +extern void oops_end(unsigned long, struct pt_regs *, int signr); #endif - 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/