Skip to content

Commit

Permalink
generic bug: use show_regs() instead of dump_stack()
Browse files Browse the repository at this point in the history
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

Acked-by: Jeremy Fitzhardinge <[email protected]>
Acked-by: 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]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
  • Loading branch information
heicarst authored and Linus Torvalds committed Jul 16, 2007
1 parent 94bed2a commit 608e261
Show file tree
Hide file tree
Showing 10 changed files with 16 additions and 12 deletions.
2 changes: 1 addition & 1 deletion arch/avr32/kernel/traps.c
Original file line number Diff line number Diff line change
Expand Up @@ -184,7 +184,7 @@ asmlinkage void do_illegal_opcode(unsigned long ecr, struct pt_regs *regs)
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;
Expand Down
2 changes: 1 addition & 1 deletion arch/i386/kernel/traps.c
Original file line number Diff line number Diff line change
Expand Up @@ -390,7 +390,7 @@ void die(const char * str, struct pt_regs * regs, long err)
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
Expand Down
2 changes: 1 addition & 1 deletion arch/parisc/kernel/traps.c
Original file line number Diff line number Diff line change
Expand Up @@ -302,7 +302,7 @@ static void handle_break(struct pt_regs *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;
Expand Down
2 changes: 1 addition & 1 deletion arch/powerpc/kernel/traps.c
Original file line number Diff line number Diff line change
Expand Up @@ -777,7 +777,7 @@ void __kprobes program_check_exception(struct pt_regs *regs)
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;
}
Expand Down
2 changes: 1 addition & 1 deletion arch/ppc/kernel/traps.c
Original file line number Diff line number Diff line change
Expand Up @@ -619,7 +619,7 @@ void program_check_exception(struct pt_regs *regs)
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;
}
Expand Down
2 changes: 1 addition & 1 deletion arch/s390/kernel/traps.c
Original file line number Diff line number Diff line change
Expand Up @@ -319,7 +319,7 @@ static void __kprobes inline do_trap(long interruption_code, int signr,
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);
Expand Down
2 changes: 1 addition & 1 deletion arch/sh/kernel/traps.c
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down
2 changes: 1 addition & 1 deletion arch/x86_64/kernel/traps.c
Original file line number Diff line number Diff line change
Expand Up @@ -531,7 +531,7 @@ void die(const char * str, struct pt_regs * regs, long err)
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);
Expand Down
7 changes: 5 additions & 2 deletions include/linux/bug.h
Original file line number Diff line number Diff line change
Expand Up @@ -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>

Expand All @@ -20,7 +22,7 @@ static inline int is_warning_bug(const struct bug_entry *bug)

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 *);
Expand All @@ -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;
}
Expand Down
5 changes: 3 additions & 2 deletions lib/bug.c
Original file line number Diff line number Diff line change
Expand Up @@ -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[];

Expand Down Expand Up @@ -112,7 +113,7 @@ const struct bug_entry *find_bug(unsigned long bugaddr)
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;
Expand Down Expand Up @@ -147,7 +148,7 @@ enum bug_trap_type report_bug(unsigned long bugaddr)
"[verbose debug info unavailable]\n",
(void *)bugaddr);

dump_stack();
show_regs(regs);
return BUG_TRAP_TYPE_WARN;
}

Expand Down

0 comments on commit 608e261

Please sign in to comment.