Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...

[linux-2.6-block.git] / arch / x86 / kernel / stacktrace.c

diff --git a/arch/x86/kernel/stacktrace.c b/arch/x86/kernel/stacktrace.c
index 60244bfaf88f69c91732929ddda712767e1ff030..093f2ea5dd56b613d03ccaeeb87fd50900f64ba1 100644 (file)
--- a/arch/x86/kernel/stacktrace.c
+++ b/arch/x86/kernel/stacktrace.c
@@ -30,7 +30,7 @@ static int save_stack_address(struct stack_trace *trace, unsigned long addr,
        return 0;
 }
 
-static void __save_stack_trace(struct stack_trace *trace,
+static void noinline __save_stack_trace(struct stack_trace *trace,
                               struct task_struct *task, struct pt_regs *regs,
                               bool nosched)
 {
@@ -56,6 +56,7 @@ static void __save_stack_trace(struct stack_trace *trace,
  */
 void save_stack_trace(struct stack_trace *trace)
 {
+       trace->skip++;
        __save_stack_trace(trace, current, NULL, false);
 }
 EXPORT_SYMBOL_GPL(save_stack_trace);
@@ -70,6 +71,8 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
        if (!try_get_task_stack(tsk))
                return;
 
+       if (tsk == current)
+               trace->skip++;
        __save_stack_trace(trace, tsk, NULL, true);
 
        put_task_stack(tsk);
@@ -88,8 +91,9 @@ EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
        }                                                       \
 })
 
-static int __save_stack_trace_reliable(struct stack_trace *trace,
-                                      struct task_struct *task)
+static int __always_inline
+__save_stack_trace_reliable(struct stack_trace *trace,
+                           struct task_struct *task)
 {
        struct unwind_state state;
        struct pt_regs *regs;
@@ -160,8 +164,12 @@ int save_stack_trace_tsk_reliable(struct task_struct *tsk,
 {
        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 -EINVAL;
+               return 0;
 
        ret = __save_stack_trace_reliable(trace, tsk);