/*
* 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;
}
void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
unsigned long *stack, char *log_lvl)
{
struct unwind_state state;
struct stack_info stack_info = {0};
unsigned long visit_mask = 0;
int graph_idx = 0;
printk("%sCall Trace:\n", log_lvl);
unwind_start(&state, task, regs, stack);
stack = stack ? : get_stack_pointer(task, regs);
/*
* 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
*/
for (regs = NULL; stack; stack = stack_info.next_sp) {
const char *stack_name;
/*
* 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 (get_stack_info(stack, task, &stack_info, &visit_mask))
break;
stack_name = stack_type_name(stack_info.type);
if (stack_name)
printk("%s <%s>\n", log_lvl, stack_name);
/*
* 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 = READ_ONCE_NOCHECK(*stack);
unsigned long *ret_addr_p =
unwind_get_return_address_ptr(&state);
if (!__kernel_text_address(addr))
continue;
/*
* Don't print regs->ip again if it was already printed
* by __show_regs() below.
*/
if (regs && stack == ®s->ip) {
unwind_next_frame(&state);
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);
/* if the frame has entry regs, print them */
regs = unwind_get_entry_regs(&state);
if (regs)
__show_regs(regs, 0);
}
if (stack_name)
printk("%s </%s>\n", log_lvl, stack_name);
}
}
