Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1765662AbXF2MUX (ORCPT ); Fri, 29 Jun 2007 08:20:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760456AbXF2MUL (ORCPT ); Fri, 29 Jun 2007 08:20:11 -0400 Received: from mtagate4.de.ibm.com ([195.212.29.153]:62618 "EHLO mtagate4.de.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758332AbXF2MUJ (ORCPT ); Fri, 29 Jun 2007 08:20:09 -0400 Date: Fri, 29 Jun 2007 14:19:59 +0200 From: Heiko Carstens To: Andrew Morton Cc: Jeremy Fitzhardinge , Haavard Skinnemoen , Andi Kleen , Kyle McMartin , Paul Mackerras , Paul Mundt , Martin Schwidefsky , linux-kernel@vger.kernel.org Subject: [patch] generic bug: use show_regs() instead of dump_stack() Message-ID: <20070629121959.GA16581@osiris.boeblingen.de.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: mutt-ng/devel-r804 (Linux) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7795 Lines: 217 [patch] generic bug: use show_regs() instead of dump_stack() From: Heiko Carstens The current generic bug implementation has a call to dump_stack() in case a WARN_ON(whatever) gets hit. Since report_bug(), which calls dump_stack(), gets called from an exception handler we can do better: just pass the pt_regs structure to report_bug() and pass it to show_regs() in case of a warning. This will give more debug informations like register contents, etc... In addition this avoids some pointless lines that dump_stack() emits, since it includes a stack backtrace of the exception handler which is of no interest in case of a warning. E.g. on s390 the following lines are currently always present in a stack backtrace if dump_stack() gets called from report_bug(): [<000000000001517a>] show_trace+0x92/0xe8) [<0000000000015270>] show_stack+0xa0/0xd0 [<00000000000152ce>] dump_stack+0x2e/0x3c [<0000000000195450>] report_bug+0x98/0xf8 [<0000000000016cc8>] illegal_op+0x1fc/0x21c [<00000000000227d6>] sysc_return+0x0/0x10 Cc: Jeremy Fitzhardinge Cc: Haavard Skinnemoen Cc: Andi Kleen Cc: Kyle McMartin Cc: Paul Mackerras Cc: Paul Mundt Cc: Martin Schwidefsky Signed-off-by: Heiko Carstens --- Patch is against current git tree. But applies against latest -mm as well. arch/avr32/kernel/traps.c | 2 +- arch/i386/kernel/traps.c | 2 +- arch/parisc/kernel/traps.c | 2 +- arch/powerpc/kernel/traps.c | 2 +- arch/ppc/kernel/traps.c | 2 +- arch/s390/kernel/traps.c | 2 +- arch/sh/kernel/traps.c | 2 +- arch/x86_64/kernel/traps.c | 2 +- include/linux/bug.h | 7 +++++-- lib/bug.c | 5 +++-- 10 files changed, 16 insertions(+), 12 deletions(-) Index: linux-2.6/arch/avr32/kernel/traps.c =================================================================== --- linux-2.6.orig/arch/avr32/kernel/traps.c +++ linux-2.6/arch/avr32/kernel/traps.c @@ -184,7 +184,7 @@ asmlinkage void do_illegal_opcode(unsign if (!user_mode(regs) && (ecr == ECR_ILLEGAL_OPCODE)) { enum bug_trap_type type; - type = report_bug(regs->pc); + type = report_bug(regs->pc, regs); switch (type) { case BUG_TRAP_TYPE_NONE: break; Index: linux-2.6/arch/i386/kernel/traps.c =================================================================== --- linux-2.6.orig/arch/i386/kernel/traps.c +++ linux-2.6/arch/i386/kernel/traps.c @@ -390,7 +390,7 @@ void die(const char * str, struct pt_reg unsigned long esp; unsigned short ss; - report_bug(regs->eip); + report_bug(regs->eip, regs); printk(KERN_EMERG "%s: %04lx [#%d]\n", str, err & 0xffff, ++die_counter); #ifdef CONFIG_PREEMPT Index: linux-2.6/arch/parisc/kernel/traps.c =================================================================== --- linux-2.6.orig/arch/parisc/kernel/traps.c +++ linux-2.6/arch/parisc/kernel/traps.c @@ -302,7 +302,7 @@ static void handle_break(struct pt_regs if (unlikely(iir == PARISC_BUG_BREAK_INSN && !user_mode(regs))) { /* check if a BUG() or WARN() trapped here. */ enum bug_trap_type tt; - tt = report_bug(regs->iaoq[0] & ~3); + tt = report_bug(regs->iaoq[0] & ~3, regs); if (tt == BUG_TRAP_TYPE_WARN) { regs->iaoq[0] += 4; regs->iaoq[1] += 4; Index: linux-2.6/arch/powerpc/kernel/traps.c =================================================================== --- linux-2.6.orig/arch/powerpc/kernel/traps.c +++ linux-2.6/arch/powerpc/kernel/traps.c @@ -777,7 +777,7 @@ void __kprobes program_check_exception(s return; if (!(regs->msr & MSR_PR) && /* not user-mode */ - report_bug(regs->nip) == BUG_TRAP_TYPE_WARN) { + report_bug(regs->nip, regs) == BUG_TRAP_TYPE_WARN) { regs->nip += 4; return; } Index: linux-2.6/arch/ppc/kernel/traps.c =================================================================== --- linux-2.6.orig/arch/ppc/kernel/traps.c +++ linux-2.6/arch/ppc/kernel/traps.c @@ -619,7 +619,7 @@ void program_check_exception(struct pt_r return; if (!(regs->msr & MSR_PR) && /* not user-mode */ - report_bug(regs->nip) == BUG_TRAP_TYPE_WARN) { + report_bug(regs->nip, regs) == BUG_TRAP_TYPE_WARN) { regs->nip += 4; return; } Index: linux-2.6/arch/s390/kernel/traps.c =================================================================== --- linux-2.6.orig/arch/s390/kernel/traps.c +++ linux-2.6/arch/s390/kernel/traps.c @@ -319,7 +319,7 @@ static void __kprobes inline do_trap(lon else { enum bug_trap_type btt; - btt = report_bug(regs->psw.addr & PSW_ADDR_INSN); + btt = report_bug(regs->psw.addr & PSW_ADDR_INSN, regs); if (btt == BUG_TRAP_TYPE_WARN) return; die(str, regs, interruption_code); Index: linux-2.6/arch/sh/kernel/traps.c =================================================================== --- linux-2.6.orig/arch/sh/kernel/traps.c +++ linux-2.6/arch/sh/kernel/traps.c @@ -874,7 +874,7 @@ void __init trap_init(void) void handle_BUG(struct pt_regs *regs) { enum bug_trap_type tt; - tt = report_bug(regs->pc); + tt = report_bug(regs->pc, regs); if (tt == BUG_TRAP_TYPE_WARN) { regs->pc += 2; return; Index: linux-2.6/arch/x86_64/kernel/traps.c =================================================================== --- linux-2.6.orig/arch/x86_64/kernel/traps.c +++ linux-2.6/arch/x86_64/kernel/traps.c @@ -531,7 +531,7 @@ void die(const char * str, struct pt_reg unsigned long flags = oops_begin(); if (!user_mode(regs)) - report_bug(regs->rip); + report_bug(regs->rip, regs); __die(str, regs, err); oops_end(flags); Index: linux-2.6/include/linux/bug.h =================================================================== --- linux-2.6.orig/include/linux/bug.h +++ linux-2.6/include/linux/bug.h @@ -10,6 +10,8 @@ enum bug_trap_type { BUG_TRAP_TYPE_BUG = 2, }; +struct pt_regs; + #ifdef CONFIG_GENERIC_BUG #include @@ -20,7 +22,7 @@ static inline int is_warning_bug(const s const struct bug_entry *find_bug(unsigned long bugaddr); -enum bug_trap_type report_bug(unsigned long bug_addr); +enum bug_trap_type report_bug(unsigned long bug_addr, struct pt_regs *regs); int module_bug_finalize(const Elf_Ehdr *, const Elf_Shdr *, struct module *); @@ -31,7 +33,8 @@ int is_valid_bugaddr(unsigned long addr) #else /* !CONFIG_GENERIC_BUG */ -static inline enum bug_trap_type report_bug(unsigned long bug_addr) +static inline enum bug_trap_type report_bug(unsigned long bug_addr, + struct pt_regs *regs) { return BUG_TRAP_TYPE_BUG; } Index: linux-2.6/lib/bug.c =================================================================== --- linux-2.6.orig/lib/bug.c +++ linux-2.6/lib/bug.c @@ -38,6 +38,7 @@ #include #include #include +#include extern const struct bug_entry __start___bug_table[], __stop___bug_table[]; @@ -112,7 +113,7 @@ const struct bug_entry *find_bug(unsigne return module_find_bug(bugaddr); } -enum bug_trap_type report_bug(unsigned long bugaddr) +enum bug_trap_type report_bug(unsigned long bugaddr, struct pt_regs *regs) { const struct bug_entry *bug; const char *file; @@ -147,7 +148,7 @@ enum bug_trap_type report_bug(unsigned l "[verbose debug info unavailable]\n", (void *)bugaddr); - dump_stack(); + show_regs(regs); return BUG_TRAP_TYPE_WARN; } - 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/