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Commit 608e2619 authored by Heiko Carstens's avatar Heiko Carstens Committed by Linus Torvalds
Browse files

generic bug: use show_regs() instead of dump_stack() 



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: default avatarJeremy Fitzhardinge <jeremy@goop.org>
Acked-by: default avatarHaavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Kyle McMartin <kyle@parisc-linux.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 94bed2a9

arch/avr32/kernel/traps.c

+1 −1
Original line number Diff line number Diff line
@@ -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;

arch/i386/kernel/traps.c

+1 −1
Original line number Diff line number Diff line
@@ -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

arch/parisc/kernel/traps.c

+1 −1
Original line number Diff line number Diff line
@@ -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;

arch/powerpc/kernel/traps.c

+1 −1
Original line number Diff line number Diff line
@@ -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;

		}

arch/ppc/kernel/traps.c

+1 −1
Original line number Diff line number Diff line
@@ -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;

		}