Merge branch 'tracing-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'tracing-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (241 commits)
  sched, trace: update trace_sched_wakeup()
  tracing/ftrace: don't trace on early stage of a secondary cpu boot, v3
  Revert "x86: disable X86_PTRACE_BTS"
  ring-buffer: prevent false positive warning
  ring-buffer: fix dangling commit race
  ftrace: enable format arguments checking
  x86, bts: memory accounting
  x86, bts: add fork and exit handling
  ftrace: introduce tracing_reset_online_cpus() helper
  tracing: fix warnings in kernel/trace/trace_sched_switch.c
  tracing: fix warning in kernel/trace/trace.c
  tracing/ring-buffer: remove unused ring_buffer size
  trace: fix task state printout
  ftrace: add not to regex on filtering functions
  trace: better use of stack_trace_enabled for boot up code
  trace: add a way to enable or disable the stack tracer
  x86: entry_64 - introduce FTRACE_ frame macro v2
  tracing/ftrace: add the printk-msg-only option
  tracing/ftrace: use preempt_enable_no_resched_notrace in ring_buffer_time_stamp()
  x86, bts: correctly report invalid bts records
  ...

Fixed up trivial conflict in scripts/recordmcount.pl due to SH bits
being already partly merged by the SH merge.

1 files changed, 64 insertions, 0 deletions

diff --git a/arch/x86/kernel/stacktrace.c b/arch/x86/kernel/stacktrace.c
index a03e7f6d90c3..10786af95545 100644
--- a/arch/x86/kernel/stacktrace.c
+++ b/arch/x86/kernel/stacktrace.c
@@ -6,6 +6,7 @@
 #include <linux/sched.h>
 #include <linux/stacktrace.h>
 #include <linux/module.h>
+#include <linux/uaccess.h>
 #include <asm/stacktrace.h>
 
 static void save_stack_warning(void *data, char *msg)
@@ -83,3 +84,66 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
                 trace->entries[trace->nr_entries++] = ULONG_MAX;
 }
 EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
+
+/* Userspace stacktrace - based on kernel/trace/trace_sysprof.c */
+
+struct stack_frame {
+        const void __user       *next_fp;
+        unsigned long           ret_addr;
+};
+
+static int copy_stack_frame(const void __user *fp, struct stack_frame *frame)
+{
+        int ret;
+
+        if (!access_ok(VERIFY_READ, fp, sizeof(*frame)))
+                return 0;
+
+        ret = 1;
+        pagefault_disable();
+        if (__copy_from_user_inatomic(frame, fp, sizeof(*frame)))
+                ret = 0;
+        pagefault_enable();
+
+        return ret;
+}
+
+static inline void __save_stack_trace_user(struct stack_trace *trace)
+{
+        const struct pt_regs *regs = task_pt_regs(current);
+        const void __user *fp = (const void __user *)regs->bp;
+
+        if (trace->nr_entries < trace->max_entries)
+                trace->entries[trace->nr_entries++] = regs->ip;
+
+        while (trace->nr_entries < trace->max_entries) {
+                struct stack_frame frame;
+
+                frame.next_fp = NULL;
+                frame.ret_addr = 0;
+                if (!copy_stack_frame(fp, &frame))
+                        break;
+                if ((unsigned long)fp < regs->sp)
+                        break;
+                if (frame.ret_addr) {
+                        trace->entries[trace->nr_entries++] =
+                                frame.ret_addr;
+                }
+                if (fp == frame.next_fp)
+                        break;
+                fp = frame.next_fp;
+        }
+}
+
+void save_stack_trace_user(struct stack_trace *trace)
+{
+        /*
+         * Trace user stack if we are not a kernel thread
+         */
+        if (current->mm) {
+                __save_stack_trace_user(trace);
+        }
+        if (trace->nr_entries < trace->max_entries)
+                trace->entries[trace->nr_entries++] = ULONG_MAX;
+}
+