Merge tag 'v3.10.107' into update

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / arch / x86 / kernel / ftrace.c

diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index e1f2e7292a54aa707b04198acb06db7647729e64..ab38db973c33b1eaa14fcdf38d7a47fae6fb2f35 100644 (file)
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -741,6 +741,18 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
        unsigned long return_hooker = (unsigned long)
                                &return_to_handler;
 
+       /*
+        * When resuming from suspend-to-ram, this function can be indirectly
+        * called from early CPU startup code while the CPU is in real mode,
+        * which would fail miserably.  Make sure the stack pointer is a
+        * virtual address.
+        *
+        * This check isn't as accurate as virt_addr_valid(), but it should be
+        * good enough for this purpose, and it's fast.
+        */
+       if (unlikely((long)__builtin_frame_address(0) >= 0))
+               return;
+
        if (unlikely(atomic_read(&current->tracing_graph_pause)))
                return;