![Ingo Molnar](/assets/img/avatar_default.png)
Framework to generate and save stacktraces quickly, without printing anything to the console. x86_64 support. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Cc: Andi Kleen <ak@muc.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
222 lines
5.4 KiB
C
222 lines
5.4 KiB
C
/*
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* arch/x86_64/kernel/stacktrace.c
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*
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* Stack trace management functions
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*
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* Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
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*/
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#include <linux/sched.h>
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#include <linux/stacktrace.h>
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#include <asm/smp.h>
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static inline int
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in_range(unsigned long start, unsigned long addr, unsigned long end)
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{
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return addr >= start && addr <= end;
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}
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static unsigned long
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get_stack_end(struct task_struct *task, unsigned long stack)
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{
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unsigned long stack_start, stack_end, flags;
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int i, cpu;
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/*
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* The most common case is that we are in the task stack:
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*/
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stack_start = (unsigned long)task->thread_info;
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stack_end = stack_start + THREAD_SIZE;
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if (in_range(stack_start, stack, stack_end))
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return stack_end;
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/*
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* We are in an interrupt if irqstackptr is set:
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*/
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raw_local_irq_save(flags);
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cpu = safe_smp_processor_id();
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stack_end = (unsigned long)cpu_pda(cpu)->irqstackptr;
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if (stack_end) {
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stack_start = stack_end & ~(IRQSTACKSIZE-1);
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if (in_range(stack_start, stack, stack_end))
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goto out_restore;
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/*
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* We get here if we are in an IRQ context but we
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* are also in an exception stack.
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*/
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}
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/*
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* Iterate over all exception stacks, and figure out whether
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* 'stack' is in one of them:
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*/
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for (i = 0; i < N_EXCEPTION_STACKS; i++) {
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/*
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* set 'end' to the end of the exception stack.
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*/
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stack_end = per_cpu(init_tss, cpu).ist[i];
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stack_start = stack_end - EXCEPTION_STKSZ;
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/*
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* Is 'stack' above this exception frame's end?
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* If yes then skip to the next frame.
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*/
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if (stack >= stack_end)
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continue;
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/*
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* Is 'stack' above this exception frame's start address?
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* If yes then we found the right frame.
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*/
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if (stack >= stack_start)
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goto out_restore;
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/*
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* If this is a debug stack, and if it has a larger size than
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* the usual exception stacks, then 'stack' might still
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* be within the lower portion of the debug stack:
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*/
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#if DEBUG_STKSZ > EXCEPTION_STKSZ
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if (i == DEBUG_STACK - 1 && stack >= stack_end - DEBUG_STKSZ) {
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/*
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* Black magic. A large debug stack is composed of
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* multiple exception stack entries, which we
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* iterate through now. Dont look:
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*/
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do {
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stack_end -= EXCEPTION_STKSZ;
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stack_start -= EXCEPTION_STKSZ;
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} while (stack < stack_start);
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goto out_restore;
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}
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#endif
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}
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/*
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* Ok, 'stack' is not pointing to any of the system stacks.
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*/
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stack_end = 0;
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out_restore:
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raw_local_irq_restore(flags);
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return stack_end;
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}
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/*
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* Save stack-backtrace addresses into a stack_trace buffer:
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*/
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static inline unsigned long
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save_context_stack(struct stack_trace *trace, unsigned int skip,
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unsigned long stack, unsigned long stack_end)
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{
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unsigned long addr;
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#ifdef CONFIG_FRAME_POINTER
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unsigned long prev_stack = 0;
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while (in_range(prev_stack, stack, stack_end)) {
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pr_debug("stack: %p\n", (void *)stack);
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addr = (unsigned long)(((unsigned long *)stack)[1]);
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pr_debug("addr: %p\n", (void *)addr);
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if (!skip)
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trace->entries[trace->nr_entries++] = addr-1;
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else
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skip--;
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if (trace->nr_entries >= trace->max_entries)
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break;
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if (!addr)
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return 0;
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/*
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* Stack frames must go forwards (otherwise a loop could
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* happen if the stackframe is corrupted), so we move
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* prev_stack forwards:
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*/
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prev_stack = stack;
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stack = (unsigned long)(((unsigned long *)stack)[0]);
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}
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pr_debug("invalid: %p\n", (void *)stack);
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#else
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while (stack < stack_end) {
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addr = ((unsigned long *)stack)[0];
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stack += sizeof(long);
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if (__kernel_text_address(addr)) {
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if (!skip)
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trace->entries[trace->nr_entries++] = addr-1;
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else
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skip--;
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if (trace->nr_entries >= trace->max_entries)
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break;
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}
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}
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#endif
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return stack;
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}
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#define MAX_STACKS 10
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/*
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* Save stack-backtrace addresses into a stack_trace buffer.
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* If all_contexts is set, all contexts (hardirq, softirq and process)
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* are saved. If not set then only the current context is saved.
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*/
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void save_stack_trace(struct stack_trace *trace,
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struct task_struct *task, int all_contexts,
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unsigned int skip)
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{
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unsigned long stack = (unsigned long)&stack;
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int i, nr_stacks = 0, stacks_done[MAX_STACKS];
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WARN_ON(trace->nr_entries || !trace->max_entries);
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if (!task)
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task = current;
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pr_debug("task: %p, ti: %p\n", task, task->thread_info);
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if (!task || task == current) {
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/* Grab rbp right from our regs: */
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asm ("mov %%rbp, %0" : "=r" (stack));
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pr_debug("rbp: %p\n", (void *)stack);
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} else {
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/* rbp is the last reg pushed by switch_to(): */
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stack = task->thread.rsp;
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pr_debug("other task rsp: %p\n", (void *)stack);
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stack = (unsigned long)(((unsigned long *)stack)[0]);
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pr_debug("other task rbp: %p\n", (void *)stack);
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}
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while (1) {
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unsigned long stack_end = get_stack_end(task, stack);
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pr_debug("stack: %p\n", (void *)stack);
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pr_debug("stack end: %p\n", (void *)stack_end);
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/*
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* Invalid stack addres?
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*/
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if (!stack_end)
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return;
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/*
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* Were we in this stack already? (recursion)
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*/
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for (i = 0; i < nr_stacks; i++)
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if (stacks_done[i] == stack_end)
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return;
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stacks_done[nr_stacks] = stack_end;
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stack = save_context_stack(trace, skip, stack, stack_end);
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if (!all_contexts || !stack ||
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trace->nr_entries >= trace->max_entries)
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return;
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trace->entries[trace->nr_entries++] = ULONG_MAX;
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if (trace->nr_entries >= trace->max_entries)
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return;
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if (++nr_stacks >= MAX_STACKS)
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return;
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}
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}
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