1 files changed, 316 insertions, 17 deletions

diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c
index f8edee9c792d..27bafc1e271e 100644
--- a/kernel/stacktrace.c
+++ b/kernel/stacktrace.c
@@ -5,41 +5,56 @@
  *
  *  Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
  */
+#include <linux/sched/task_stack.h>
+#include <linux/sched/debug.h>
 #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)
+/**
+ * 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(print_stack_trace);
+EXPORT_SYMBOL_GPL(stack_trace_print);
 
-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;
@@ -51,7 +66,176 @@ int snprint_stack_trace(char *buf, size_t size,
 
         return total;
 }
-EXPORT_SYMBOL_GPL(snprint_stack_trace);
+EXPORT_SYMBOL_GPL(stack_trace_snprint);
+
+#ifdef CONFIG_ARCH_STACKWALK
+
+struct stacktrace_cookie {
+        unsigned long   *store;
+        unsigned int    size;
+        unsigned int    skip;
+        unsigned int    len;
+};
+
+static bool stack_trace_consume_entry(void *cookie, unsigned long addr,
+                                      bool reliable)
+{
+        struct stacktrace_cookie *c = cookie;
+
+        if (c->len >= c->size)
+                return false;
+
+        if (c->skip > 0) {
+                c->skip--;
+                return true;
+        }
+        c->store[c->len++] = addr;
+        return c->len < c->size;
+}
+
+static bool stack_trace_consume_entry_nosched(void *cookie, unsigned long addr,
+                                              bool reliable)
+{
+        if (in_sched_functions(addr))
+                return true;
+        return stack_trace_consume_entry(cookie, addr, reliable);
+}
+
+/**
+ * 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)
+{
+        stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
+        struct stacktrace_cookie c = {
+                .store  = store,
+                .size   = size,
+                .skip   = skipnr + 1,
+        };
+
+        arch_stack_walk(consume_entry, &c, current, NULL);
+        return c.len;
+}
+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 *tsk, unsigned long *store,
+                                  unsigned int size, unsigned int skipnr)
+{
+        stack_trace_consume_fn consume_entry = stack_trace_consume_entry_nosched;
+        struct stacktrace_cookie c = {
+                .store  = store,
+                .size   = size,
+                .skip   = skipnr + 1,
+        };
+
+        if (!try_get_task_stack(tsk))
+                return 0;
+
+        arch_stack_walk(consume_entry, &c, tsk, NULL);
+        put_task_stack(tsk);
+        return c.len;
+}
+
+/**
+ * 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)
+{
+        stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
+        struct stacktrace_cookie c = {
+                .store  = store,
+                .size   = size,
+                .skip   = skipnr,
+        };
+
+        arch_stack_walk(consume_entry, &c, current, regs);
+        return c.len;
+}
+
+#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)
+{
+        stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
+        struct stacktrace_cookie c = {
+                .store  = store,
+                .size   = size,
+        };
+        int ret;
+
+        /*
+         * If the task doesn't have a stack (e.g., a zombie), the stack is
+         * "reliably" empty.
+         */
+        if (!try_get_task_stack(tsk))
+                return 0;
+
+        ret = arch_stack_walk_reliable(consume_entry, &c, tsk);
+        put_task_stack(tsk);
+        return ret;
+}
+#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)
+{
+        stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
+        struct stacktrace_cookie c = {
+                .store  = store,
+                .size   = size,
+        };
+
+        /* Trace user stack if not a kernel thread */
+        if (!current->mm)
+                return 0;
+
+        arch_stack_walk_user(consume_entry, &c, task_pt_regs(current));
+        return c.len;
+}
+#endif
+
+#else /* CONFIG_ARCH_STACKWALK */
 
 /*
  * Architectures that do not implement save_stack_trace_*()
@@ -77,3 +261,118 @@ 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 */
+
+#endif /* !CONFIG_ARCH_STACKWALK */