#include <linux/sysfs.h>
#include <asm/stacktrace.h>
-
+#include <asm/unwind.h>
int panic_on_unrecovered_nmi;
int panic_on_io_nmi;
int kstack_depth_to_print = 3 * STACKSLOTS_PER_LINE;
static int die_counter;
+bool in_task_stack(unsigned long *stack, struct task_struct *task,
+ struct stack_info *info)
+{
+ unsigned long *begin = task_stack_page(task);
+ unsigned long *end = task_stack_page(task) + THREAD_SIZE;
+
+ if (stack < begin || stack >= end)
+ return false;
+
+ info->type = STACK_TYPE_TASK;
+ info->begin = begin;
+ info->end = end;
+ info->next_sp = NULL;
+
+ return true;
+}
+
static void printk_stack_address(unsigned long address, int reliable,
- void *data)
+ char *log_lvl)
{
+ touch_nmi_watchdog();
printk("%s [<%p>] %s%pB\n",
- (char *)data, (void *)address, reliable ? "" : "? ",
+ log_lvl, (void *)address, reliable ? "" : "? ",
(void *)address);
}
pr_cont(" [<%p>] %pS\n", (void *)address, (void *)address);
}
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-static void
-print_ftrace_graph_addr(unsigned long addr, void *data,
- const struct stacktrace_ops *ops,
- struct task_struct *task, int *graph)
+void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
+ unsigned long *stack, char *log_lvl)
{
- unsigned long ret_addr;
- int index;
-
- if (addr != (unsigned long)return_to_handler)
- return;
-
- index = task->curr_ret_stack;
-
- if (!task->ret_stack || index < *graph)
- return;
-
- index -= *graph;
- ret_addr = task->ret_stack[index].ret;
-
- ops->address(data, ret_addr, 1);
+ struct unwind_state state;
+ struct stack_info stack_info = {0};
+ unsigned long visit_mask = 0;
+ int graph_idx = 0;
- (*graph)++;
-}
-#else
-static inline void
-print_ftrace_graph_addr(unsigned long addr, void *data,
- const struct stacktrace_ops *ops,
- struct task_struct *task, int *graph)
-{ }
-#endif
-
-/*
- * x86-64 can have up to three kernel stacks:
- * process stack
- * interrupt stack
- * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
- */
-
-static inline int valid_stack_ptr(struct task_struct *task,
- void *p, unsigned int size, void *end)
-{
- void *t = task_stack_page(task);
- if (end) {
- if (p < end && p >= (end-THREAD_SIZE))
- return 1;
- else
- return 0;
- }
- return p >= t && p < t + THREAD_SIZE - size;
-}
+ printk("%sCall Trace:\n", log_lvl);
-unsigned long
-print_context_stack(struct task_struct *task,
- unsigned long *stack, unsigned long bp,
- const struct stacktrace_ops *ops, void *data,
- unsigned long *end, int *graph)
-{
- struct stack_frame *frame = (struct stack_frame *)bp;
+ unwind_start(&state, task, regs, stack);
/*
- * If we overflowed the stack into a guard page, jump back to the
- * bottom of the usable stack.
+ * Iterate through the stacks, starting with the current stack pointer.
+ * Each stack has a pointer to the next one.
+ *
+ * x86-64 can have several stacks:
+ * - task stack
+ * - interrupt stack
+ * - HW exception stacks (double fault, nmi, debug, mce)
+ *
+ * x86-32 can have up to three stacks:
+ * - task stack
+ * - softirq stack
+ * - hardirq stack
*/
- if ((unsigned long)task_stack_page(task) - (unsigned long)stack <
- PAGE_SIZE)
- stack = (unsigned long *)task_stack_page(task);
-
- while (valid_stack_ptr(task, stack, sizeof(*stack), end)) {
- unsigned long addr;
-
- addr = *stack;
- if (__kernel_text_address(addr)) {
- if ((unsigned long) stack == bp + sizeof(long)) {
- ops->address(data, addr, 1);
- frame = frame->next_frame;
- bp = (unsigned long) frame;
- } else {
- ops->address(data, addr, 0);
- }
- print_ftrace_graph_addr(addr, data, ops, task, graph);
- }
- stack++;
- }
- return bp;
-}
-EXPORT_SYMBOL_GPL(print_context_stack);
-
-unsigned long
-print_context_stack_bp(struct task_struct *task,
- unsigned long *stack, unsigned long bp,
- const struct stacktrace_ops *ops, void *data,
- unsigned long *end, int *graph)
-{
- struct stack_frame *frame = (struct stack_frame *)bp;
- unsigned long *ret_addr = &frame->return_address;
+ for (; stack; stack = stack_info.next_sp) {
+ const char *str_begin, *str_end;
- while (valid_stack_ptr(task, ret_addr, sizeof(*ret_addr), end)) {
- unsigned long addr = *ret_addr;
+ /*
+ * If we overflowed the task stack into a guard page, jump back
+ * to the bottom of the usable stack.
+ */
+ if (task_stack_page(task) - (void *)stack < PAGE_SIZE)
+ stack = task_stack_page(task);
- if (!__kernel_text_address(addr))
+ if (get_stack_info(stack, task, &stack_info, &visit_mask))
break;
- if (ops->address(data, addr, 1))
- break;
- frame = frame->next_frame;
- ret_addr = &frame->return_address;
- print_ftrace_graph_addr(addr, data, ops, task, graph);
- }
-
- return (unsigned long)frame;
-}
-EXPORT_SYMBOL_GPL(print_context_stack_bp);
-
-static int print_trace_stack(void *data, char *name)
-{
- printk("%s <%s> ", (char *)data, name);
- return 0;
-}
-
-/*
- * Print one address/symbol entries per line.
- */
-static int print_trace_address(void *data, unsigned long addr, int reliable)
-{
- touch_nmi_watchdog();
- printk_stack_address(addr, reliable, data);
- return 0;
-}
-
-static const struct stacktrace_ops print_trace_ops = {
- .stack = print_trace_stack,
- .address = print_trace_address,
- .walk_stack = print_context_stack,
-};
-
-void
-show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
- unsigned long *stack, unsigned long bp, char *log_lvl)
-{
- printk("%sCall Trace:\n", log_lvl);
- dump_trace(task, regs, stack, bp, &print_trace_ops, log_lvl);
-}
+ stack_type_str(stack_info.type, &str_begin, &str_end);
+ if (str_begin)
+ printk("%s <%s> ", log_lvl, str_begin);
+
+ /*
+ * Scan the stack, printing any text addresses we find. At the
+ * same time, follow proper stack frames with the unwinder.
+ *
+ * Addresses found during the scan which are not reported by
+ * the unwinder are considered to be additional clues which are
+ * sometimes useful for debugging and are prefixed with '?'.
+ * This also serves as a failsafe option in case the unwinder
+ * goes off in the weeds.
+ */
+ for (; stack < stack_info.end; stack++) {
+ unsigned long real_addr;
+ int reliable = 0;
+ unsigned long addr = *stack;
+ unsigned long *ret_addr_p =
+ unwind_get_return_address_ptr(&state);
+
+ if (!__kernel_text_address(addr))
+ continue;
+
+ if (stack == ret_addr_p)
+ reliable = 1;
+
+ /*
+ * When function graph tracing is enabled for a
+ * function, its return address on the stack is
+ * replaced with the address of an ftrace handler
+ * (return_to_handler). In that case, before printing
+ * the "real" address, we want to print the handler
+ * address as an "unreliable" hint that function graph
+ * tracing was involved.
+ */
+ real_addr = ftrace_graph_ret_addr(task, &graph_idx,
+ addr, stack);
+ if (real_addr != addr)
+ printk_stack_address(addr, 0, log_lvl);
+ printk_stack_address(real_addr, reliable, log_lvl);
+
+ if (!reliable)
+ continue;
+
+ /*
+ * Get the next frame from the unwinder. No need to
+ * check for an error: if anything goes wrong, the rest
+ * of the addresses will just be printed as unreliable.
+ */
+ unwind_next_frame(&state);
+ }
-void show_trace(struct task_struct *task, struct pt_regs *regs,
- unsigned long *stack, unsigned long bp)
-{
- show_trace_log_lvl(task, regs, stack, bp, "");
+ if (str_end)
+ printk("%s <%s> ", log_lvl, str_end);
+ }
}
void show_stack(struct task_struct *task, unsigned long *sp)
{
- unsigned long bp = 0;
- unsigned long stack;
+ task = task ? : current;
/*
* Stack frames below this one aren't interesting. Don't show them
* if we're printing for %current.
*/
- if (!sp && (!task || task == current)) {
- sp = &stack;
- bp = stack_frame(current, NULL);
- }
+ if (!sp && task == current)
+ sp = get_stack_pointer(current, NULL);
- show_stack_log_lvl(task, NULL, sp, bp, "");
+ show_stack_log_lvl(current, NULL, sp, "");
}
void show_stack_regs(struct pt_regs *regs)
{
- show_stack_log_lvl(current, regs, (unsigned long *)regs->sp, regs->bp, "");
+ show_stack_log_lvl(current, regs, NULL, "");
}
static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
projects / cascardo / linux.git / blobdiff