From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755085AbYAPWdK (ORCPT ); Wed, 16 Jan 2008 17:33:10 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756798AbYAPW1L (ORCPT ); Wed, 16 Jan 2008 17:27:11 -0500 Received: from mx2.suse.de ([195.135.220.15]:39467 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756248AbYAPW1I (ORCPT ); Wed, 16 Jan 2008 17:27:08 -0500 From: Andi Kleen References: <200801161127.268350000@suse.de> In-Reply-To: <200801161127.268350000@suse.de> To: mingo@elte.hu, tglx@linutronix.de, linux-kernel@vger.kernel.org Subject: [PATCH] [4/7] Print which shared library/executable faulted in segfault etc. messages Message-Id: <20080116222707.904DF14EE3@wotan.suse.de> Date: Wed, 16 Jan 2008 23:27:07 +0100 (CET) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org They now look like hal-resmgr[13791]: segfault at 3c rip 2b9c8caec182 rsp 7fff1e825d30 error 4 in libacl.so.1.1.0[2b9c8caea000+6000] This makes it easier to pinpoint bugs to specific libraries. And printing the offset into a mapping also always allows to find the correct fault point in a library even with randomized mappings. Previously there was no way to actually find the correct code address inside the randomized mapping. Relies on earlier patch to shorten the printk formats. They are often now longer than 80 characters, but I think that's worth it. Patch for i386 and x86-64. [includes fix from Eric Dumazet to check d_path error value] Signed-off-by: Andi Kleen --- arch/x86/kernel/signal_32.c | 7 +++++-- arch/x86/kernel/signal_64.c | 7 +++++-- arch/x86/kernel/traps_32.c | 7 +++++-- arch/x86/mm/fault_32.c | 4 +++- include/linux/mm.h | 1 + mm/memory.c | 31 +++++++++++++++++++++++++++++++ 6 files changed, 50 insertions(+), 7 deletions(-) Index: linux/include/linux/mm.h =================================================================== --- linux.orig/include/linux/mm.h +++ linux/include/linux/mm.h @@ -1145,6 +1145,7 @@ extern int randomize_va_space; #endif const char * arch_vma_name(struct vm_area_struct *vma); +void print_vma_addr(char *prefix, unsigned long rip); struct page *sparse_mem_map_populate(unsigned long pnum, int nid); pgd_t *vmemmap_pgd_populate(unsigned long addr, int node); Index: linux/mm/memory.c =================================================================== --- linux.orig/mm/memory.c +++ linux/mm/memory.c @@ -2746,3 +2746,34 @@ int access_process_vm(struct task_struct return buf - old_buf; } + +/* + * Print the name of a VMA. + */ +void print_vma_addr(char *prefix, unsigned long ip) +{ + struct mm_struct *mm = current->mm; + struct vm_area_struct *vma; + + down_read(&mm->mmap_sem); + vma = find_vma(mm, ip); + if (vma && vma->vm_file) { + struct file *f = vma->vm_file; + char *buf = (char *)__get_free_page(GFP_KERNEL); + if (buf) { + char *p, *s; + + p = d_path(f->f_dentry, f->f_vfsmnt, buf, PAGE_SIZE); + if (IS_ERR(p)) + p = "?"; + s = strrchr(p, '/'); + if (s) + p = s+1; + printk("%s%s[%lx+%lx]", prefix, p, + vma->vm_start, + vma->vm_end - vma->vm_start); + free_page((unsigned long)buf); + } + } + up_read(¤t->mm->mmap_sem); +} Index: linux/arch/x86/kernel/signal_32.c =================================================================== --- linux.orig/arch/x86/kernel/signal_32.c +++ linux/arch/x86/kernel/signal_32.c @@ -198,12 +198,15 @@ asmlinkage int sys_sigreturn(unsigned lo return ax; badframe: - if (show_unhandled_signals && printk_ratelimit()) + if (show_unhandled_signals && printk_ratelimit()) { printk("%s%s[%d] bad frame in sigreturn frame:%p ip:%lx" - " sp:%lx oeax:%lx\n", + " sp:%lx oeax:%lx", task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG, current->comm, task_pid_nr(current), frame, regs->ip, regs->sp, regs->orig_ax); + print_vma_addr(" in ", regs->ip); + printk("\n"); + } force_sig(SIGSEGV, current); return 0; Index: linux/arch/x86/kernel/signal_64.c =================================================================== --- linux.orig/arch/x86/kernel/signal_64.c +++ linux/arch/x86/kernel/signal_64.c @@ -481,9 +481,12 @@ do_notify_resume(struct pt_regs *regs, v void signal_fault(struct pt_regs *regs, void __user *frame, char *where) { struct task_struct *me = current; - if (show_unhandled_signals && printk_ratelimit()) - printk("%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx\n", + if (show_unhandled_signals && printk_ratelimit()) { + printk("%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx", me->comm,me->pid,where,frame,regs->ip,regs->sp,regs->orig_ax); + print_vma_addr(" in ", regs->ip); + printk("\n"); + } force_sig(SIGSEGV, me); } Index: linux/arch/x86/kernel/traps_32.c =================================================================== --- linux.orig/arch/x86/kernel/traps_32.c +++ linux/arch/x86/kernel/traps_32.c @@ -608,11 +608,14 @@ void __kprobes do_general_protection(str current->thread.error_code = error_code; current->thread.trap_no = 13; if (show_unhandled_signals && unhandled_signal(current, SIGSEGV) && - printk_ratelimit()) + printk_ratelimit()) { printk(KERN_INFO - "%s[%d] general protection ip:%lx sp:%lx error:%lx\n", + "%s[%d] general protection ip:%lx sp:%lx error:%lx", current->comm, task_pid_nr(current), regs->ip, regs->sp, error_code); + print_vma_addr(" in ", regs->ip); + printk("\n"); + } force_sig(SIGSEGV, current); return; Index: linux/arch/x86/mm/fault_32.c =================================================================== --- linux.orig/arch/x86/mm/fault_32.c +++ linux/arch/x86/mm/fault_32.c @@ -518,11 +518,13 @@ bad_area_nosemaphore: #ifdef CONFIG_X86_32 "%s%s[%d]: segfault at %lx ip %08lx sp %08lx error %lx\n", #else - "%s%s[%d]: segfault at %lx ip %lx sp %lx error %lx\n", + "%s%s[%d]: segfault at %lx ip %lx sp %lx error %lx", #endif task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG, tsk->comm, task_pid_nr(tsk), address, regs->ip, regs->sp, error_code); + print_vma_addr(" in ", regs->ip); + printk("\n"); } tsk->thread.cr2 = address; /* Kernel addresses are always protection faults */