static void __stp_stack_print(struct pt_regs *regs, int verbose, int levels,
struct task_struct *tsk,
struct uretprobe_instance *ri, int uregs_valid)
{
#ifdef STP_USE_DWARF_UNWINDER
int start_levels = levels;
// FIXME: large stack allocation
struct unwind_frame_info info;
int sanitize = tsk && ! uregs_valid;
arch_unw_init_frame_info(&info, regs, sanitize);
while (levels && (tsk || !arch_unw_user_mode(&info))) {
int ret = unwind(&info, tsk);
#ifdef STAPCONF_UPROBE_GET_PC
unsigned long maybe_pc = 0;
if (ri) {
maybe_pc = uprobe_get_pc(ri, UNW_PC(&info),
UNW_SP(&info));
if (!maybe_pc)
printk("SYSTEMTAP ERROR: uprobe_get_return returned 0\n");
else
UNW_PC(&info) = maybe_pc;
}
#endif
dbug_unwind(1, "ret=%d PC=%lx SP=%lx\n", ret, UNW_PC(&info), UNW_SP(&info));
if (ret == 0) {
_stp_print_addr(UNW_PC(&info), verbose, tsk);
levels--;
if (UNW_PC(&info) != _stp_kretprobe_trampoline)
continue;
}
/* If an error happened or we hit a kretprobe trampoline,
* use fallback backtrace, unless user task backtrace.
* FIXME: is there a way to unwind across kretprobe
* trampolines? PR9999. */
if ((ret < 0
|| UNW_PC(&info) == _stp_kretprobe_trampoline)
&& ! (tsk || arch_unw_user_mode(&info)))
_stp_stack_print_fallback(UNW_SP(&info), verbose, levels);
return;
}
#else /* ! STP_USE_DWARF_UNWINDER */
_stp_stack_print_fallback(REG_SP(regs), verbose, levels);
#endif
}
static int asmlinkage dump_trace_unwind(struct unwind_frame_info *info,
const struct stacktrace_ops *ops,
void *data)
{
int n = 0;
#ifdef CONFIG_STACK_UNWIND
unsigned long sp = UNW_SP(info);
if (arch_unw_user_mode(info))
return -1;
while (unwind(info) == 0 && UNW_PC(info)) {
n++;
ops->address(data, UNW_PC(info), 1);
if (arch_unw_user_mode(info))
break;
if ((sp & ~(PAGE_SIZE - 1)) == (UNW_SP(info) & ~(PAGE_SIZE - 1))
&& sp > UNW_SP(info))
break;
sp = UNW_SP(info);
}
#endif
return n;
}
int try_stack_unwind(struct task_struct *task, struct pt_regs *regs,
unsigned long **stack, unsigned long *bp,
const struct stacktrace_ops *ops, void *data)
{
#ifdef CONFIG_STACK_UNWIND
int unw_ret = 0;
struct unwind_frame_info info;
if (call_trace < 0)
return 0;
if (regs) {
if (unwind_init_frame_info(&info, task, regs) == 0)
unw_ret = dump_trace_unwind(&info, ops, data);
} else if (task == current)
unw_ret = unwind_init_running(&info, dump_trace_unwind, ops, data);
#ifdef CONFIG_SMP
else if (task->on_cpu)
/* nothing */;
#endif
else if (unwind_init_blocked(&info, task) == 0)
unw_ret = dump_trace_unwind(&info, ops, data);
if (unw_ret > 0) {
if (call_trace == 1 && !arch_unw_user_mode(&info)) {
ops->warning_symbol(data, "DWARF2 unwinder stuck at %s\n",
UNW_PC(&info));
if (UNW_SP(&info) >= PAGE_OFFSET) {
ops->warning(data, "Leftover inexact backtrace:\n");
*stack = (void *)UNW_SP(&info);
*bp = UNW_FP(&info);
return 0;
}
} else if (call_trace >= 1)
return -1;
ops->warning(data, "Full inexact backtrace again:\n");
} else
ops->warning(data, "Inexact backtrace:\n");
#endif
return 0;
}
