File-copy from v4.4.100
This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Please refer to that tree for all history prior to this point.
Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c
new file mode 100644
index 0000000..b6e4c16
--- /dev/null
+++ b/kernel/stacktrace.c
@@ -0,0 +1,75 @@
+/*
+ * kernel/stacktrace.c
+ *
+ * Stack trace management functions
+ *
+ * Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ */
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/kallsyms.h>
+#include <linux/stacktrace.h>
+
+void print_stack_trace(struct stack_trace *trace, int spaces)
+{
+ int i;
+
+ if (WARN_ON(!trace->entries))
+ return;
+
+ for (i = 0; i < trace->nr_entries; i++) {
+ printk("%*c", 1 + spaces, ' ');
+ print_ip_sym(trace->entries[i]);
+ }
+}
+EXPORT_SYMBOL_GPL(print_stack_trace);
+
+int snprint_stack_trace(char *buf, size_t size,
+ struct stack_trace *trace, int spaces)
+{
+ int i;
+ unsigned long ip;
+ int generated;
+ int total = 0;
+
+ if (WARN_ON(!trace->entries))
+ return 0;
+
+ for (i = 0; i < trace->nr_entries; i++) {
+ ip = trace->entries[i];
+ generated = snprintf(buf, size, "%*c[<%p>] %pS\n",
+ 1 + spaces, ' ', (void *) ip, (void *) ip);
+
+ total += generated;
+
+ /* Assume that generated isn't a negative number */
+ if (generated >= size) {
+ buf += size;
+ size = 0;
+ } else {
+ buf += generated;
+ size -= generated;
+ }
+ }
+
+ return total;
+}
+EXPORT_SYMBOL_GPL(snprint_stack_trace);
+
+/*
+ * Architectures that do not implement save_stack_trace_tsk or
+ * save_stack_trace_regs get this weak alias and a once-per-bootup warning
+ * (whenever this facility is utilized - for example by procfs):
+ */
+__weak void
+save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
+{
+ WARN_ONCE(1, KERN_INFO "save_stack_trace_tsk() not implemented yet.\n");
+}
+
+__weak void
+save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
+{
+ WARN_ONCE(1, KERN_INFO "save_stack_trace_regs() not implemented yet.\n");
+}