sh: unwinder: Fix up invalid PC refetch in dwarf unwinder.

The dwarf unwinder presently attempts to provide a sane PC value if none
is provided, however the logic is broken and cases where a previous valid
dwarf frame exists along with a bogus PC value can still proceed. This
fixes up the test and prevents the unwinder from blowing up.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/arch/sh/kernel/dwarf.c b/arch/sh/kernel/dwarf.c
index 2d07084e4882..d76a23170dbb 100644
--- a/arch/sh/kernel/dwarf.c
+++ b/arch/sh/kernel/dwarf.c
@@ -555,7 +555,7 @@ 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