From 0a65800243742480b4b594b619b759749a3cfef4 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sat, 16 Apr 2005 15:25:17 -0700 Subject: [PATCH] x86_64: Rewrite exception stack backtracing Exceptions and hardware interrupts can, to a certain degree, nest, so when attempting to follow the sequence of stacks used in order to dump their contents this has to be accounted for. Also, IST stacks have their tops stored in the TSS, so there's no need to add the stack size to get to their ends. Minor changes from AK. Signed-off-by: Jan Beulich Signed-off-by: Andi Kleen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/x86_64/kernel/traps.c | 147 ++++++++++++++++++++++++--------------------- 1 file changed, 79 insertions(+), 68 deletions(-) (limited to 'arch') diff --git a/arch/x86_64/kernel/traps.c b/arch/x86_64/kernel/traps.c index f6ccf155e3e..65a37f52c56 100644 --- a/arch/x86_64/kernel/traps.c +++ b/arch/x86_64/kernel/traps.c @@ -120,95 +120,106 @@ int printk_address(unsigned long address) } #endif -unsigned long *in_exception_stack(int cpu, unsigned long stack) -{ - int k; +static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack, + unsigned *usedp, const char **idp) +{ + static const char ids[N_EXCEPTION_STACKS][8] = { + [DEBUG_STACK - 1] = "#DB", + [NMI_STACK - 1] = "NMI", + [DOUBLEFAULT_STACK - 1] = "#DF", + [STACKFAULT_STACK - 1] = "#SS", + [MCE_STACK - 1] = "#MC", + }; + unsigned k; + for (k = 0; k < N_EXCEPTION_STACKS; k++) { - struct tss_struct *tss = &per_cpu(init_tss, cpu); - unsigned long start = tss->ist[k] - EXCEPTION_STKSZ; + unsigned long end; - if (stack >= start && stack < tss->ist[k]) - return (unsigned long *)tss->ist[k]; + end = per_cpu(init_tss, cpu).ist[k]; + if (stack >= end) + continue; + if (stack >= end - EXCEPTION_STKSZ) { + if (*usedp & (1U << k)) + break; + *usedp |= 1U << k; + *idp = ids[k]; + return (unsigned long *)end; + } } return NULL; -} +} /* * x86-64 can have upto three kernel stacks: * process stack * interrupt stack - * severe exception (double fault, nmi, stack fault) hardware stack - * Check and process them in order. + * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack */ void show_trace(unsigned long *stack) { unsigned long addr; - unsigned long *irqstack, *irqstack_end, *estack_end; - const int cpu = safe_smp_processor_id(); + const unsigned cpu = safe_smp_processor_id(); + unsigned long *irqstack_end = (unsigned long *)cpu_pda[cpu].irqstackptr; int i; + unsigned used = 0; printk("\nCall Trace:"); - i = 0; - - estack_end = in_exception_stack(cpu, (unsigned long)stack); - if (estack_end) { - while (stack < estack_end) { - addr = *stack++; - if (__kernel_text_address(addr)) { - i += printk_address(addr); - i += printk(" "); - if (i > 50) { - printk("\n"); - i = 0; - } - } + +#define HANDLE_STACK(cond) \ + do while (cond) { \ + addr = *stack++; \ + if (kernel_text_address(addr)) { \ + /* \ + * If the address is either in the text segment of the \ + * kernel, or in the region which contains vmalloc'ed \ + * memory, it *may* be the address of a calling \ + * routine; if so, print it so that someone tracing \ + * down the cause of the crash will be able to figure \ + * out the call path that was taken. \ + */ \ + i += printk_address(addr); \ + if (i > 50) { \ + printk("\n "); \ + i = 0; \ + } \ + else \ + i += printk(" "); \ + } \ + } while (0) + + for(i = 0; ; ) { + const char *id; + unsigned long *estack_end; + estack_end = in_exception_stack(cpu, (unsigned long)stack, + &used, &id); + + if (estack_end) { + i += printk(" <%s> ", id); + HANDLE_STACK (stack < estack_end); + i += printk(" "); + stack = (unsigned long *) estack_end[-2]; + continue; } - i += printk(" "); - i += 7; - stack = (unsigned long *) estack_end[-2]; - } - - irqstack_end = (unsigned long *) (cpu_pda[cpu].irqstackptr); - irqstack = (unsigned long *) (cpu_pda[cpu].irqstackptr - IRQSTACKSIZE + 64); - - if (stack >= irqstack && stack < irqstack_end) { - printk(" "); - while (stack < irqstack_end) { - addr = *stack++; - /* - * If the address is either in the text segment of the - * kernel, or in the region which contains vmalloc'ed - * memory, it *may* be the address of a calling - * routine; if so, print it so that someone tracing - * down the cause of the crash will be able to figure - * out the call path that was taken. - */ - if (__kernel_text_address(addr)) { - i += printk_address(addr); - i += printk(" "); - if (i > 50) { - printk("\n "); - i = 0; - } + if (irqstack_end) { + unsigned long *irqstack; + irqstack = irqstack_end - + (IRQSTACKSIZE - 64) / sizeof(*irqstack); + + if (stack >= irqstack && stack < irqstack_end) { + i += printk(" "); + HANDLE_STACK (stack < irqstack_end); + stack = (unsigned long *) (irqstack_end[-1]); + irqstack_end = NULL; + i += printk(" "); + continue; } - } - stack = (unsigned long *) (irqstack_end[-1]); - printk(" "); - i += 7; - } - - while (((long) stack & (THREAD_SIZE-1)) != 0) { - addr = *stack++; - if (__kernel_text_address(addr)) { - i += printk_address(addr); - i += printk(" "); - if (i > 50) { - printk("\n "); - i = 0; - } } + break; } + + HANDLE_STACK (((long) stack & (THREAD_SIZE-1)) != 0); +#undef HANDLE_STACK printk("\n"); } -- cgit v1.2.3-70-g09d2