Merge git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-rc-fixes-2.6

[sfrench/cifs-2.6.git] / arch / sh / kernel / dwarf.c

diff --git a/arch/sh/kernel/dwarf.c b/arch/sh/kernel/dwarf.c
index 03b3616c80a5e164502b0d4d4a77e35831348de3..d76a23170dbb7d0a6e8cd1aef093ba48431e3b84 100644 (file)
--- a/arch/sh/kernel/dwarf.c
+++ b/arch/sh/kernel/dwarf.c
@@ -20,6 +20,7 @@
 #include <linux/list.h>
 #include <linux/mempool.h>
 #include <linux/mm.h>
+#include <linux/ftrace.h>
 #include <asm/dwarf.h>
 #include <asm/unwinder.h>
 #include <asm/sections.h>
@@ -554,9 +555,30 @@ struct dwarf_frame * dwarf_unwind_stack(unsigned long pc,
         * NOTE: the return address is guaranteed to be setup by the
         * time this function makes its first function call.
         */
-       if (!pc && !prev)
+       if (!pc || !prev)
                pc = (unsigned long)current_text_addr();
 
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+       /*
+        * If our stack has been patched by the function graph tracer
+        * then we might see the address of return_to_handler() where we
+        * expected to find the real return address.
+        */
+       if (pc == (unsigned long)&return_to_handler) {
+               int index = current->curr_ret_stack;
+
+               /*
+                * We currently have no way of tracking how many
+                * return_to_handler()'s we've seen. If there is more
+                * than one patched return address on our stack,
+                * complain loudly.
+                */
+               WARN_ON(index > 0);
+
+               pc = current->ret_stack[index].ret;
+       }
+#endif
+
        frame = mempool_alloc(dwarf_frame_pool, GFP_ATOMIC);
        if (!frame) {
                printk(KERN_ERR "Unable to allocate a dwarf frame\n");