2 files changed, 182 insertions, 15 deletions

diff --git a/include/linux/stacktrace.h b/include/linux/stacktrace.h
index ba29a0613e66..a24340b3e9e1 100644
--- a/include/linux/stacktrace.h
+++ b/include/linux/stacktrace.h
@@ -3,11 +3,26 @@
 #define __LINUX_STACKTRACE_H
 
 #include <linux/types.h>
+#include <asm/errno.h>
 
 struct task_struct;
 struct pt_regs;
 
 #ifdef CONFIG_STACKTRACE
+void stack_trace_print(unsigned long *trace, unsigned int nr_entries,
+                       int spaces);
+int stack_trace_snprint(char *buf, size_t size, unsigned long *entries,
+                        unsigned int nr_entries, int spaces);
+unsigned int stack_trace_save(unsigned long *store, unsigned int size,
+                              unsigned int skipnr);
+unsigned int stack_trace_save_tsk(struct task_struct *task,
+                                  unsigned long *store, unsigned int size,
+                                  unsigned int skipnr);
+unsigned int stack_trace_save_regs(struct pt_regs *regs, unsigned long *store,
+                                   unsigned int size, unsigned int skipnr);
+unsigned int stack_trace_save_user(unsigned long *store, unsigned int size);
+
+/* Internal interfaces. Do not use in generic code */
 struct stack_trace {
         unsigned int nr_entries, max_entries;
         unsigned long *entries;
@@ -41,4 +56,16 @@ extern void save_stack_trace_user(struct stack_trace *trace);
 # define save_stack_trace_tsk_reliable(tsk, trace)      ({ -ENOSYS; })
 #endif /* CONFIG_STACKTRACE */
 
+#if defined(CONFIG_STACKTRACE) && defined(CONFIG_HAVE_RELIABLE_STACKTRACE)
+int stack_trace_save_tsk_reliable(struct task_struct *tsk, unsigned long *store,
+                                  unsigned int size);
+#else
+static inline int stack_trace_save_tsk_reliable(struct task_struct *tsk,
+                                                unsigned long *store,
+                                                unsigned int size)
+{
+        return -ENOSYS;
+}
+#endif
+
 #endif /* __LINUX_STACKTRACE_H */
diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c
index f8edee9c792d..b38333b3bc18 100644
--- a/kernel/stacktrace.c
+++ b/kernel/stacktrace.c
@@ -11,35 +11,54 @@
 #include <linux/kallsyms.h>
 #include <linux/stacktrace.h>
 
-void print_stack_trace(struct stack_trace *trace, int spaces)
+/**
+ * stack_trace_print - Print the entries in the stack trace
+ * @entries:    Pointer to storage array
+ * @nr_entries: Number of entries in the storage array
+ * @spaces:     Number of leading spaces to print
+ */
+void stack_trace_print(unsigned long *entries, unsigned int nr_entries,
+                       int spaces)
 {
-        int i;
+        unsigned int i;
 
-        if (WARN_ON(!trace->entries))
+        if (WARN_ON(!entries))
                 return;
 
-        for (i = 0; i < trace->nr_entries; i++)
-                printk("%*c%pS\n", 1 + spaces, ' ', (void *)trace->entries[i]);
+        for (i = 0; i < nr_entries; i++)
+                printk("%*c%pS\n", 1 + spaces, ' ', (void *)entries[i]);
+}
+EXPORT_SYMBOL_GPL(stack_trace_print);
+
+void print_stack_trace(struct stack_trace *trace, int spaces)
+{
+        stack_trace_print(trace->entries, trace->nr_entries, spaces);
 }
 EXPORT_SYMBOL_GPL(print_stack_trace);
 
-int snprint_stack_trace(char *buf, size_t size,
-                        struct stack_trace *trace, int spaces)
+/**
+ * stack_trace_snprint - Print the entries in the stack trace into a buffer
+ * @buf:        Pointer to the print buffer
+ * @size:       Size of the print buffer
+ * @entries:    Pointer to storage array
+ * @nr_entries: Number of entries in the storage array
+ * @spaces:     Number of leading spaces to print
+ *
+ * Return: Number of bytes printed.
+ */
+int stack_trace_snprint(char *buf, size_t size, unsigned long *entries,
+                        unsigned int nr_entries, int spaces)
 {
-        int i;
-        int generated;
-        int total = 0;
+        unsigned int generated, i, total = 0;
 
-        if (WARN_ON(!trace->entries))
+        if (WARN_ON(!entries))
                 return 0;
 
-        for (i = 0; i < trace->nr_entries; i++) {
+        for (i = 0; i < nr_entries && size; i++) {
                 generated = snprintf(buf, size, "%*c%pS\n", 1 + spaces, ' ',
-                                     (void *)trace->entries[i]);
+                                     (void *)entries[i]);
 
                 total += generated;
-
-                /* Assume that generated isn't a negative number */
                 if (generated >= size) {
                         buf += size;
                         size = 0;
@@ -51,6 +70,14 @@ int snprint_stack_trace(char *buf, size_t size,
 
         return total;
 }
+EXPORT_SYMBOL_GPL(stack_trace_snprint);
+
+int snprint_stack_trace(char *buf, size_t size,
+                        struct stack_trace *trace, int spaces)
+{
+        return stack_trace_snprint(buf, size, trace->entries,
+                                   trace->nr_entries, spaces);
+}
 EXPORT_SYMBOL_GPL(snprint_stack_trace);
 
 /*
@@ -77,3 +104,116 @@ save_stack_trace_tsk_reliable(struct task_struct *tsk,
         WARN_ONCE(1, KERN_INFO "save_stack_tsk_reliable() not implemented yet.\n");
         return -ENOSYS;
 }
+
+/**
+ * stack_trace_save - Save a stack trace into a storage array
+ * @store:      Pointer to storage array
+ * @size:       Size of the storage array
+ * @skipnr:     Number of entries to skip at the start of the stack trace
+ *
+ * Return: Number of trace entries stored
+ */
+unsigned int stack_trace_save(unsigned long *store, unsigned int size,
+                              unsigned int skipnr)
+{
+        struct stack_trace trace = {
+                .entries        = store,
+                .max_entries    = size,
+                .skip           = skipnr + 1,
+        };
+
+        save_stack_trace(&trace);
+        return trace.nr_entries;
+}
+EXPORT_SYMBOL_GPL(stack_trace_save);
+
+/**
+ * stack_trace_save_tsk - Save a task stack trace into a storage array
+ * @task:       The task to examine
+ * @store:      Pointer to storage array
+ * @size:       Size of the storage array
+ * @skipnr:     Number of entries to skip at the start of the stack trace
+ *
+ * Return: Number of trace entries stored
+ */
+unsigned int stack_trace_save_tsk(struct task_struct *task,
+                                  unsigned long *store, unsigned int size,
+                                  unsigned int skipnr)
+{
+        struct stack_trace trace = {
+                .entries        = store,
+                .max_entries    = size,
+                .skip           = skipnr + 1,
+        };
+
+        save_stack_trace_tsk(task, &trace);
+        return trace.nr_entries;
+}
+
+/**
+ * stack_trace_save_regs - Save a stack trace based on pt_regs into a storage array
+ * @regs:       Pointer to pt_regs to examine
+ * @store:      Pointer to storage array
+ * @size:       Size of the storage array
+ * @skipnr:     Number of entries to skip at the start of the stack trace
+ *
+ * Return: Number of trace entries stored
+ */
+unsigned int stack_trace_save_regs(struct pt_regs *regs, unsigned long *store,
+                                   unsigned int size, unsigned int skipnr)
+{
+        struct stack_trace trace = {
+                .entries        = store,
+                .max_entries    = size,
+                .skip           = skipnr,
+        };
+
+        save_stack_trace_regs(regs, &trace);
+        return trace.nr_entries;
+}
+
+#ifdef CONFIG_HAVE_RELIABLE_STACKTRACE
+/**
+ * stack_trace_save_tsk_reliable - Save task stack with verification
+ * @tsk:        Pointer to the task to examine
+ * @store:      Pointer to storage array
+ * @size:       Size of the storage array
+ *
+ * Return:      An error if it detects any unreliable features of the
+ *              stack. Otherwise it guarantees that the stack trace is
+ *              reliable and returns the number of entries stored.
+ *
+ * If the task is not 'current', the caller *must* ensure the task is inactive.
+ */
+int stack_trace_save_tsk_reliable(struct task_struct *tsk, unsigned long *store,
+                                  unsigned int size)
+{
+        struct stack_trace trace = {
+                .entries        = store,
+                .max_entries    = size,
+        };
+        int ret = save_stack_trace_tsk_reliable(tsk, &trace);
+
+        return ret ? ret : trace.nr_entries;
+}
+#endif
+
+#ifdef CONFIG_USER_STACKTRACE_SUPPORT
+/**
+ * stack_trace_save_user - Save a user space stack trace into a storage array
+ * @store:      Pointer to storage array
+ * @size:       Size of the storage array
+ *
+ * Return: Number of trace entries stored
+ */
+unsigned int stack_trace_save_user(unsigned long *store, unsigned int size)
+{
+        struct stack_trace trace = {
+                .entries        = store,
+                .max_entries    = size,
+        };
+
+        save_stack_trace_user(&trace);
+        return trace.nr_entries;
+}
+#endif /* CONFIG_USER_STACKTRACE_SUPPORT */