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-rw-r--r--arch/powerpc/kernel/process.c26
-rw-r--r--arch/powerpc/kernel/stacktrace.c29
2 files changed, 49 insertions, 6 deletions
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 71bad4b6f80d..791bd8ea475d 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -2027,7 +2027,7 @@ int validate_sp(unsigned long sp, struct task_struct *p,
EXPORT_SYMBOL(validate_sp);
-unsigned long get_wchan(struct task_struct *p)
+static unsigned long __get_wchan(struct task_struct *p)
{
unsigned long ip, sp;
int count = 0;
@@ -2053,6 +2053,20 @@ unsigned long get_wchan(struct task_struct *p)
return 0;
}
+unsigned long get_wchan(struct task_struct *p)
+{
+ unsigned long ret;
+
+ if (!try_get_task_stack(p))
+ return 0;
+
+ ret = __get_wchan(p);
+
+ put_task_stack(p);
+
+ return ret;
+}
+
static int kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH;
void show_stack(struct task_struct *tsk, unsigned long *stack)
@@ -2067,9 +2081,13 @@ void show_stack(struct task_struct *tsk, unsigned long *stack)
int curr_frame = 0;
#endif
- sp = (unsigned long) stack;
if (tsk == NULL)
tsk = current;
+
+ if (!try_get_task_stack(tsk))
+ return;
+
+ sp = (unsigned long) stack;
if (sp == 0) {
if (tsk == current)
sp = current_stack_pointer();
@@ -2081,7 +2099,7 @@ void show_stack(struct task_struct *tsk, unsigned long *stack)
printk("Call Trace:\n");
do {
if (!validate_sp(sp, tsk, STACK_FRAME_OVERHEAD))
- return;
+ break;
stack = (unsigned long *) sp;
newsp = stack[0];
@@ -2121,6 +2139,8 @@ void show_stack(struct task_struct *tsk, unsigned long *stack)
sp = newsp;
} while (count++ < kstack_depth_to_print);
+
+ put_task_stack(tsk);
}
#ifdef CONFIG_PPC64
diff --git a/arch/powerpc/kernel/stacktrace.c b/arch/powerpc/kernel/stacktrace.c
index cf31ce6c1f53..f958f3bcba04 100644
--- a/arch/powerpc/kernel/stacktrace.c
+++ b/arch/powerpc/kernel/stacktrace.c
@@ -67,12 +67,17 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
{
unsigned long sp;
+ if (!try_get_task_stack(tsk))
+ return;
+
if (tsk == current)
sp = current_stack_pointer();
else
sp = tsk->thread.ksp;
save_context_stack(trace, sp, tsk, 0);
+
+ put_task_stack(tsk);
}
EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
@@ -90,9 +95,8 @@ EXPORT_SYMBOL_GPL(save_stack_trace_regs);
*
* If the task is not 'current', the caller *must* ensure the task is inactive.
*/
-int
-save_stack_trace_tsk_reliable(struct task_struct *tsk,
- struct stack_trace *trace)
+static int __save_stack_trace_tsk_reliable(struct task_struct *tsk,
+ struct stack_trace *trace)
{
unsigned long sp;
unsigned long newsp;
@@ -197,6 +201,25 @@ save_stack_trace_tsk_reliable(struct task_struct *tsk,
}
return 0;
}
+
+int save_stack_trace_tsk_reliable(struct task_struct *tsk,
+ struct stack_trace *trace)
+{
+ 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 = __save_stack_trace_tsk_reliable(tsk, trace);
+
+ put_task_stack(tsk);
+
+ return ret;
+}
EXPORT_SYMBOL_GPL(save_stack_trace_tsk_reliable);
#endif /* CONFIG_HAVE_RELIABLE_STACKTRACE */