[patch] generic bug: use show_regs() instead of dump_stack()
From: Heiko Carstens <[email protected]>
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 <[email protected]>
Cc: Haavard Skinnemoen <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Kyle McMartin <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Paul Mundt <[email protected]>
Cc: Martin Schwidefsky <[email protected]>
Signed-off-by: Heiko Carstens <[email protected]>
---
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 <asm-generic/bug.h>
@@ -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 <linux/list.h>
#include <linux/module.h>
#include <linux/bug.h>
+#include <linux/sched.h>
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;
}
-
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