if (kbt->verbose)
pr_err(" <%s while in kernel mode>\n", fault);
} else if (EX1_PL(p->ex1) == USER_PL &&
- p->pc < PAGE_OFFSET &&
- p->sp < PAGE_OFFSET) {
+ p->sp < PAGE_OFFSET && p->sp != 0) {
if (kbt->verbose)
pr_err(" <%s while in user mode>\n", fault);
} else if (kbt->verbose) {
vma->vm_start, vma->vm_end - vma->vm_start);
}
+/*
+ * Avoid possible crash recursion during backtrace. If it happens, it
+ * makes it easy to lose the actual root cause of the failure, so we
+ * put a simple guard on all the backtrace loops.
+ */
+static bool start_backtrace(void)
+{
+ if (current->thread.in_backtrace) {
+ pr_err("Backtrace requested while in backtrace!\n");
+ return false;
+ }
+ current->thread.in_backtrace = true;
+ return true;
+}
+
+static void end_backtrace(void)
+{
+ current->thread.in_backtrace = false;
+}
+
/*
* This method wraps the backtracer's more generic support.
* It is only invoked from the architecture-specific code; show_stack()
int i;
int have_mmap_sem = 0;
+ if (!start_backtrace())
+ return;
if (headers) {
/*
* Add a blank line since if we are called from panic(),
pr_err("Stack dump complete\n");
if (have_mmap_sem)
up_read(&kbt->task->mm->mmap_sem);
+ end_backtrace();
}
EXPORT_SYMBOL(tile_show_stack);
int skip = trace->skip;
int i = 0;
+ if (!start_backtrace())
+ goto done;
if (task == NULL || task == current)
KBacktraceIterator_init_current(&kbt);
else
break;
trace->entries[i++] = kbt.it.pc;
}
+ end_backtrace();
+done:
trace->nr_entries = i;
}
EXPORT_SYMBOL(save_stack_trace_tsk);