![Andy Shevchenko](/assets/img/avatar_default.png)
kbasename() returns the filename part of a pathname. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
518 lines
14 KiB
C
518 lines
14 KiB
C
/*
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* Copyright 2010 Tilera Corporation. All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation, version 2.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
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* NON INFRINGEMENT. See the GNU General Public License for
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* more details.
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*/
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/kprobes.h>
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#include <linux/module.h>
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#include <linux/pfn.h>
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#include <linux/kallsyms.h>
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#include <linux/stacktrace.h>
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#include <linux/uaccess.h>
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#include <linux/mmzone.h>
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#include <linux/dcache.h>
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#include <linux/fs.h>
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#include <linux/string.h>
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#include <asm/backtrace.h>
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#include <asm/page.h>
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#include <asm/ucontext.h>
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#include <asm/switch_to.h>
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#include <asm/sigframe.h>
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#include <asm/stack.h>
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#include <asm/vdso.h>
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#include <arch/abi.h>
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#include <arch/interrupts.h>
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#define KBT_ONGOING 0 /* Backtrace still ongoing */
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#define KBT_DONE 1 /* Backtrace cleanly completed */
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#define KBT_RUNNING 2 /* Can't run backtrace on a running task */
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#define KBT_LOOP 3 /* Backtrace entered a loop */
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/* Is address on the specified kernel stack? */
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static int in_kernel_stack(struct KBacktraceIterator *kbt, unsigned long sp)
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{
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ulong kstack_base = (ulong) kbt->task->stack;
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if (kstack_base == 0) /* corrupt task pointer; just follow stack... */
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return sp >= PAGE_OFFSET && sp < (unsigned long)high_memory;
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return sp >= kstack_base && sp < kstack_base + THREAD_SIZE;
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}
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/* Callback for backtracer; basically a glorified memcpy */
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static bool read_memory_func(void *result, unsigned long address,
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unsigned int size, void *vkbt)
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{
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int retval;
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struct KBacktraceIterator *kbt = (struct KBacktraceIterator *)vkbt;
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if (address == 0)
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return 0;
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if (__kernel_text_address(address)) {
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/* OK to read kernel code. */
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} else if (address >= PAGE_OFFSET) {
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/* We only tolerate kernel-space reads of this task's stack */
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if (!in_kernel_stack(kbt, address))
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return 0;
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} else if (!kbt->is_current) {
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return 0; /* can't read from other user address spaces */
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}
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pagefault_disable();
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retval = __copy_from_user_inatomic(result,
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(void __user __force *)address,
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size);
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pagefault_enable();
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return (retval == 0);
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}
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/* Return a pt_regs pointer for a valid fault handler frame */
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static struct pt_regs *valid_fault_handler(struct KBacktraceIterator* kbt)
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{
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const char *fault = NULL; /* happy compiler */
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char fault_buf[64];
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unsigned long sp = kbt->it.sp;
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struct pt_regs *p;
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if (sp % sizeof(long) != 0)
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return NULL;
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if (!in_kernel_stack(kbt, sp))
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return NULL;
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if (!in_kernel_stack(kbt, sp + C_ABI_SAVE_AREA_SIZE + PTREGS_SIZE-1))
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return NULL;
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p = (struct pt_regs *)(sp + C_ABI_SAVE_AREA_SIZE);
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if (p->faultnum == INT_SWINT_1 || p->faultnum == INT_SWINT_1_SIGRETURN)
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fault = "syscall";
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else {
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if (kbt->verbose) { /* else we aren't going to use it */
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snprintf(fault_buf, sizeof(fault_buf),
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"interrupt %ld", p->faultnum);
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fault = fault_buf;
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}
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}
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if (EX1_PL(p->ex1) == KERNEL_PL &&
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__kernel_text_address(p->pc) &&
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in_kernel_stack(kbt, p->sp) &&
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p->sp >= sp) {
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if (kbt->verbose)
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pr_err(" <%s while in kernel mode>\n", fault);
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} else if (user_mode(p) &&
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p->sp < PAGE_OFFSET && p->sp != 0) {
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if (kbt->verbose)
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pr_err(" <%s while in user mode>\n", fault);
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} else if (kbt->verbose) {
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pr_err(" (odd fault: pc %#lx, sp %#lx, ex1 %#lx?)\n",
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p->pc, p->sp, p->ex1);
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p = NULL;
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}
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if (!kbt->profile || ((1ULL << p->faultnum) & QUEUED_INTERRUPTS) == 0)
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return p;
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return NULL;
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}
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/* Is the pc pointing to a sigreturn trampoline? */
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static int is_sigreturn(unsigned long pc)
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{
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return current->mm && (pc == VDSO_SYM(&__vdso_rt_sigreturn));
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}
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/* Return a pt_regs pointer for a valid signal handler frame */
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static struct pt_regs *valid_sigframe(struct KBacktraceIterator* kbt,
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struct rt_sigframe* kframe)
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{
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BacktraceIterator *b = &kbt->it;
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if (is_sigreturn(b->pc) && b->sp < PAGE_OFFSET &&
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b->sp % sizeof(long) == 0) {
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int retval;
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pagefault_disable();
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retval = __copy_from_user_inatomic(
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kframe, (void __user __force *)b->sp,
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sizeof(*kframe));
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pagefault_enable();
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if (retval != 0 ||
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(unsigned int)(kframe->info.si_signo) >= _NSIG)
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return NULL;
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if (kbt->verbose) {
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pr_err(" <received signal %d>\n",
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kframe->info.si_signo);
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}
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return (struct pt_regs *)&kframe->uc.uc_mcontext;
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}
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return NULL;
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}
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static int KBacktraceIterator_is_sigreturn(struct KBacktraceIterator *kbt)
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{
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return is_sigreturn(kbt->it.pc);
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}
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static int KBacktraceIterator_restart(struct KBacktraceIterator *kbt)
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{
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struct pt_regs *p;
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struct rt_sigframe kframe;
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p = valid_fault_handler(kbt);
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if (p == NULL)
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p = valid_sigframe(kbt, &kframe);
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if (p == NULL)
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return 0;
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backtrace_init(&kbt->it, read_memory_func, kbt,
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p->pc, p->lr, p->sp, p->regs[52]);
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kbt->new_context = 1;
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return 1;
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}
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/* Find a frame that isn't a sigreturn, if there is one. */
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static int KBacktraceIterator_next_item_inclusive(
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struct KBacktraceIterator *kbt)
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{
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for (;;) {
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do {
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if (!KBacktraceIterator_is_sigreturn(kbt))
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return KBT_ONGOING;
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} while (backtrace_next(&kbt->it));
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if (!KBacktraceIterator_restart(kbt))
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return KBT_DONE;
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}
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}
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/*
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* If the current sp is on a page different than what we recorded
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* as the top-of-kernel-stack last time we context switched, we have
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* probably blown the stack, and nothing is going to work out well.
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* If we can at least get out a warning, that may help the debug,
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* though we probably won't be able to backtrace into the code that
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* actually did the recursive damage.
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*/
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static void validate_stack(struct pt_regs *regs)
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{
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int cpu = raw_smp_processor_id();
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unsigned long ksp0 = get_current_ksp0();
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unsigned long ksp0_base = ksp0 & -THREAD_SIZE;
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unsigned long sp = stack_pointer;
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if (EX1_PL(regs->ex1) == KERNEL_PL && regs->sp >= ksp0) {
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pr_err("WARNING: cpu %d: kernel stack %#lx..%#lx underrun!\n"
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" sp %#lx (%#lx in caller), caller pc %#lx, lr %#lx\n",
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cpu, ksp0_base, ksp0, sp, regs->sp, regs->pc, regs->lr);
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}
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else if (sp < ksp0_base + sizeof(struct thread_info)) {
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pr_err("WARNING: cpu %d: kernel stack %#lx..%#lx overrun!\n"
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" sp %#lx (%#lx in caller), caller pc %#lx, lr %#lx\n",
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cpu, ksp0_base, ksp0, sp, regs->sp, regs->pc, regs->lr);
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}
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}
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void KBacktraceIterator_init(struct KBacktraceIterator *kbt,
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struct task_struct *t, struct pt_regs *regs)
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{
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unsigned long pc, lr, sp, r52;
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int is_current;
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/*
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* Set up callback information. We grab the kernel stack base
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* so we will allow reads of that address range.
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*/
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is_current = (t == NULL || t == current);
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kbt->is_current = is_current;
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if (is_current)
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t = validate_current();
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kbt->task = t;
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kbt->verbose = 0; /* override in caller if desired */
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kbt->profile = 0; /* override in caller if desired */
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kbt->end = KBT_ONGOING;
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kbt->new_context = 1;
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if (is_current)
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validate_stack(regs);
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if (regs == NULL) {
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if (is_current || t->state == TASK_RUNNING) {
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/* Can't do this; we need registers */
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kbt->end = KBT_RUNNING;
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return;
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}
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pc = get_switch_to_pc();
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lr = t->thread.pc;
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sp = t->thread.ksp;
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r52 = 0;
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} else {
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pc = regs->pc;
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lr = regs->lr;
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sp = regs->sp;
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r52 = regs->regs[52];
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}
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backtrace_init(&kbt->it, read_memory_func, kbt, pc, lr, sp, r52);
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kbt->end = KBacktraceIterator_next_item_inclusive(kbt);
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}
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EXPORT_SYMBOL(KBacktraceIterator_init);
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int KBacktraceIterator_end(struct KBacktraceIterator *kbt)
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{
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return kbt->end != KBT_ONGOING;
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}
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EXPORT_SYMBOL(KBacktraceIterator_end);
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void KBacktraceIterator_next(struct KBacktraceIterator *kbt)
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{
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unsigned long old_pc = kbt->it.pc, old_sp = kbt->it.sp;
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kbt->new_context = 0;
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if (!backtrace_next(&kbt->it) && !KBacktraceIterator_restart(kbt)) {
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kbt->end = KBT_DONE;
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return;
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}
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kbt->end = KBacktraceIterator_next_item_inclusive(kbt);
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if (old_pc == kbt->it.pc && old_sp == kbt->it.sp) {
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/* Trapped in a loop; give up. */
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kbt->end = KBT_LOOP;
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}
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}
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EXPORT_SYMBOL(KBacktraceIterator_next);
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static void describe_addr(struct KBacktraceIterator *kbt,
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unsigned long address,
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int have_mmap_sem, char *buf, size_t bufsize)
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{
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struct vm_area_struct *vma;
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size_t namelen, remaining;
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unsigned long size, offset, adjust;
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char *p, *modname;
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const char *name;
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int rc;
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/*
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* Look one byte back for every caller frame (i.e. those that
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* aren't a new context) so we look up symbol data for the
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* call itself, not the following instruction, which may be on
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* a different line (or in a different function).
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*/
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adjust = !kbt->new_context;
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address -= adjust;
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if (address >= PAGE_OFFSET) {
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/* Handle kernel symbols. */
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BUG_ON(bufsize < KSYM_NAME_LEN);
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name = kallsyms_lookup(address, &size, &offset,
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&modname, buf);
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if (name == NULL) {
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buf[0] = '\0';
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return;
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}
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namelen = strlen(buf);
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remaining = (bufsize - 1) - namelen;
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p = buf + namelen;
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rc = snprintf(p, remaining, "+%#lx/%#lx ",
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offset + adjust, size);
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if (modname && rc < remaining)
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snprintf(p + rc, remaining - rc, "[%s] ", modname);
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buf[bufsize-1] = '\0';
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return;
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}
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/* If we don't have the mmap_sem, we can't show any more info. */
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buf[0] = '\0';
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if (!have_mmap_sem)
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return;
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/* Find vma info. */
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vma = find_vma(kbt->task->mm, address);
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if (vma == NULL || address < vma->vm_start) {
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snprintf(buf, bufsize, "[unmapped address] ");
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return;
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}
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if (vma->vm_file) {
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p = d_path(&vma->vm_file->f_path, buf, bufsize);
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if (IS_ERR(p))
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p = "?";
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name = kbasename(p);
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} else {
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name = "anon";
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}
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/* Generate a string description of the vma info. */
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namelen = strlen(name);
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remaining = (bufsize - 1) - namelen;
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memmove(buf, name, namelen);
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snprintf(buf + namelen, remaining, "[%lx+%lx] ",
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vma->vm_start, vma->vm_end - vma->vm_start);
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}
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/*
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* Avoid possible crash recursion during backtrace. If it happens, it
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* makes it easy to lose the actual root cause of the failure, so we
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* put a simple guard on all the backtrace loops.
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*/
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static bool start_backtrace(void)
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{
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if (current->thread.in_backtrace) {
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pr_err("Backtrace requested while in backtrace!\n");
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return false;
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}
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current->thread.in_backtrace = true;
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return true;
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}
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static void end_backtrace(void)
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{
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current->thread.in_backtrace = false;
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}
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/*
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* This method wraps the backtracer's more generic support.
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* It is only invoked from the architecture-specific code; show_stack()
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* and dump_stack() (in entry.S) are architecture-independent entry points.
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*/
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void tile_show_stack(struct KBacktraceIterator *kbt, int headers)
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{
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int i;
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int have_mmap_sem = 0;
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if (!start_backtrace())
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return;
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if (headers) {
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/*
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* Add a blank line since if we are called from panic(),
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* then bust_spinlocks() spit out a space in front of us
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* and it will mess up our KERN_ERR.
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*/
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pr_err("\n");
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pr_err("Starting stack dump of tid %d, pid %d (%s)"
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" on cpu %d at cycle %lld\n",
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kbt->task->pid, kbt->task->tgid, kbt->task->comm,
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raw_smp_processor_id(), get_cycles());
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}
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kbt->verbose = 1;
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i = 0;
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for (; !KBacktraceIterator_end(kbt); KBacktraceIterator_next(kbt)) {
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char namebuf[KSYM_NAME_LEN+100];
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unsigned long address = kbt->it.pc;
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/* Try to acquire the mmap_sem as we pass into userspace. */
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if (address < PAGE_OFFSET && !have_mmap_sem && kbt->task->mm)
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have_mmap_sem =
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down_read_trylock(&kbt->task->mm->mmap_sem);
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describe_addr(kbt, address, have_mmap_sem,
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namebuf, sizeof(namebuf));
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pr_err(" frame %d: 0x%lx %s(sp 0x%lx)\n",
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i++, address, namebuf, (unsigned long)(kbt->it.sp));
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if (i >= 100) {
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pr_err("Stack dump truncated"
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" (%d frames)\n", i);
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break;
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}
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}
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if (kbt->end == KBT_LOOP)
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pr_err("Stack dump stopped; next frame identical to this one\n");
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if (headers)
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pr_err("Stack dump complete\n");
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if (have_mmap_sem)
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up_read(&kbt->task->mm->mmap_sem);
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end_backtrace();
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}
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EXPORT_SYMBOL(tile_show_stack);
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/* This is called from show_regs() and _dump_stack() */
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void dump_stack_regs(struct pt_regs *regs)
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{
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struct KBacktraceIterator kbt;
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KBacktraceIterator_init(&kbt, NULL, regs);
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tile_show_stack(&kbt, 1);
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}
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EXPORT_SYMBOL(dump_stack_regs);
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static struct pt_regs *regs_to_pt_regs(struct pt_regs *regs,
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ulong pc, ulong lr, ulong sp, ulong r52)
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{
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memset(regs, 0, sizeof(struct pt_regs));
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regs->pc = pc;
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regs->lr = lr;
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regs->sp = sp;
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regs->regs[52] = r52;
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return regs;
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}
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/* This is called from dump_stack() and just converts to pt_regs */
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void _dump_stack(int dummy, ulong pc, ulong lr, ulong sp, ulong r52)
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{
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struct pt_regs regs;
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dump_stack_regs(regs_to_pt_regs(®s, pc, lr, sp, r52));
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}
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/* This is called from KBacktraceIterator_init_current() */
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void _KBacktraceIterator_init_current(struct KBacktraceIterator *kbt, ulong pc,
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ulong lr, ulong sp, ulong r52)
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{
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struct pt_regs regs;
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KBacktraceIterator_init(kbt, NULL,
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regs_to_pt_regs(®s, pc, lr, sp, r52));
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}
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/* This is called only from kernel/sched/core.c, with esp == NULL */
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void show_stack(struct task_struct *task, unsigned long *esp)
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{
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struct KBacktraceIterator kbt;
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if (task == NULL || task == current)
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KBacktraceIterator_init_current(&kbt);
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else
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KBacktraceIterator_init(&kbt, task, NULL);
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tile_show_stack(&kbt, 0);
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}
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#ifdef CONFIG_STACKTRACE
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/* Support generic Linux stack API too */
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void save_stack_trace_tsk(struct task_struct *task, struct stack_trace *trace)
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{
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struct KBacktraceIterator kbt;
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int skip = trace->skip;
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int i = 0;
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if (!start_backtrace())
|
|
goto done;
|
|
if (task == NULL || task == current)
|
|
KBacktraceIterator_init_current(&kbt);
|
|
else
|
|
KBacktraceIterator_init(&kbt, task, NULL);
|
|
for (; !KBacktraceIterator_end(&kbt); KBacktraceIterator_next(&kbt)) {
|
|
if (skip) {
|
|
--skip;
|
|
continue;
|
|
}
|
|
if (i >= trace->max_entries || kbt.it.pc < PAGE_OFFSET)
|
|
break;
|
|
trace->entries[i++] = kbt.it.pc;
|
|
}
|
|
end_backtrace();
|
|
done:
|
|
trace->nr_entries = i;
|
|
}
|
|
EXPORT_SYMBOL(save_stack_trace_tsk);
|
|
|
|
void save_stack_trace(struct stack_trace *trace)
|
|
{
|
|
save_stack_trace_tsk(NULL, trace);
|
|
}
|
|
EXPORT_SYMBOL_GPL(save_stack_trace);
|
|
|
|
#endif
|
|
|
|
/* In entry.S */
|
|
EXPORT_SYMBOL(KBacktraceIterator_init_current);
|