Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932929AbXFEVxc (ORCPT ); Tue, 5 Jun 2007 17:53:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933760AbXFEVxG (ORCPT ); Tue, 5 Jun 2007 17:53:06 -0400 Received: from smtp-out.google.com ([216.239.33.17]:14586 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933644AbXFEVxE (ORCPT ); Tue, 5 Jun 2007 17:53:04 -0400 DomainKey-Signature: a=rsa-sha1; s=beta; d=google.com; c=nofws; q=dns; h=received:date:to:subject:message-id:mime-version: content-type:content-disposition:user-agent:from; b=RxFAlJl59ktZaH/q5b6uNPO0rXbAmADKN8HjeOh7DVgpl+PuRYQ+yx5ZyARQVCXQP pwCpQ0acKCwZAtQJnMtYw== Date: Tue, 5 Jun 2007 14:52:44 -0700 To: akpm@linux-foundation.org, linux-kernel@vger.kernel.org Subject: [PATCH] Make i386 kernel show the segfaults in kernel dmesg, like x86_64. Message-ID: <20070605215242.GA16967@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.11 From: masouds@google.com (Masoud Asgharifard Sharbiani) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4769 Lines: 160 Hello, This patch makes the i386 behave the same way that x86_64 does when a segfault happens. A line gets printed to the kernel log so that tools that need to check for failures can behave more uniformly between different kernels. Like x86_64, it can be disabled by setting debug.exception-trace sysctl variable to 0 (or by doing echo 0 > /proc/sys/debug/exception-trace) Same behaviour can be extended to other architectures, if needed. cheers, Masoud. Signed-off-by: Masoud Sharbiani diff --git a/arch/i386/mm/fault.c b/arch/i386/mm/fault.c index 29d7d61..6aa56db 100644 --- a/arch/i386/mm/fault.c +++ b/arch/i386/mm/fault.c @@ -283,6 +283,8 @@ static inline int vmalloc_fault(unsigned long address) return 0; } +int exception_trace = 1; + /* * This routine handles page faults. It determines the address, * and the problem, and then passes it off to one of the appropriate @@ -464,7 +466,14 @@ bad_area_nosemaphore: */ if (is_prefetch(regs, address, error_code)) return; - + if (exception_trace && unhandled_signal(tsk, SIGSEGV)) { + printk( + "%s%s[%d]: segfault at %08lx eip %08lx esp %08lx error %lx\n", + tsk->pid > 1 ? KERN_INFO : KERN_EMERG, + tsk->comm, tsk->pid, address, regs->eip, + regs->esp, error_code); + } + tsk->thread.cr2 = address; /* Kernel addresses are always protection faults */ tsk->thread.error_code = error_code | (address >= TASK_SIZE); diff --git a/arch/i386/mm/init.c b/arch/i386/mm/init.c index b22ce8d..a300ff8 100644 --- a/arch/i386/mm/init.c +++ b/arch/i386/mm/init.c @@ -854,3 +854,39 @@ void free_initrd_mem(unsigned long start, unsigned long end) } #endif +#ifdef CONFIG_SYSCTL +#include + +extern int exception_trace; + +static ctl_table debug_table2[] = { + { + .ctl_name = 99, + .procname = "exception-trace", + .data = &exception_trace, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec + }, + {} +}; + +static ctl_table debug_root_table2[] = { + { + .ctl_name = CTL_DEBUG, + .procname = "debug", + .mode = 0555, + .child = debug_table2 + }, + {} +}; + +static __init int i386_sysctl_init(void) +{ + register_sysctl_table(debug_root_table2); + return 0; +} +__initcall(i386_sysctl_init); +#endif + + diff --git a/arch/x86_64/mm/fault.c b/arch/x86_64/mm/fault.c index bfb62a1..863189a 100644 --- a/arch/x86_64/mm/fault.c +++ b/arch/x86_64/mm/fault.c @@ -221,16 +221,6 @@ static int is_errata93(struct pt_regs *regs, unsigned long address) return 0; } -int unhandled_signal(struct task_struct *tsk, int sig) -{ - if (is_init(tsk)) - return 1; - if (tsk->ptrace & PT_PTRACED) - return 0; - return (tsk->sighand->action[sig-1].sa.sa_handler == SIG_IGN) || - (tsk->sighand->action[sig-1].sa.sa_handler == SIG_DFL); -} - static noinline void pgtable_bad(unsigned long address, struct pt_regs *regs, unsigned long error_code) { diff --git a/include/asm-x86_64/proto.h b/include/asm-x86_64/proto.h index 85255db..4fad501 100644 --- a/include/asm-x86_64/proto.h +++ b/include/asm-x86_64/proto.h @@ -75,8 +75,6 @@ extern void setup_node_bootmem(int nodeid, unsigned long start, unsigned long en extern void early_quirks(void); extern void check_efer(void); -extern int unhandled_signal(struct task_struct *tsk, int sig); - extern void select_idle_routine(const struct cpuinfo_x86 *c); extern unsigned long table_start, table_end; diff --git a/include/linux/signal.h b/include/linux/signal.h index 9a5eac5..1ebe715 100644 --- a/include/linux/signal.h +++ b/include/linux/signal.h @@ -244,6 +244,8 @@ extern int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka, extern struct kmem_cache *sighand_cachep; +int unhandled_signal(struct task_struct *tsk, int sig); + /* * In POSIX a signal is sent either to a specific thread (Linux task) * or to the process as a whole (Linux thread group). How the signal diff --git a/kernel/signal.c b/kernel/signal.c index 364fc95..6ae6aac 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -174,6 +174,16 @@ static struct sigqueue *__sigqueue_alloc(struct task_struct *t, gfp_t flags, return(q); } +int unhandled_signal(struct task_struct *tsk, int sig) +{ + if (is_init(tsk)) + return 1; + if (tsk->ptrace & PT_PTRACED) + return 0; + return (tsk->sighand->action[sig-1].sa.sa_handler == SIG_IGN) || + (tsk->sighand->action[sig-1].sa.sa_handler == SIG_DFL); +} + static void __sigqueue_free(struct sigqueue *q) { if (q->flags & SIGQUEUE_PREALLOC) - 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/