sparc64: Handle stack trace attempts before irqstacks are setup.

Things like lockdep can try to do stack backtraces before
the irqstack blocks have been setup.  So don't try to match
their ranges so early on.

Also, remove unused variable in save_stack_trace().

Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 21 insertions, 20 deletions

diff --git a/arch/sparc64/kernel/kstack.h b/arch/sparc64/kernel/kstack.h
index 43909d5680ea..4248d969272f 100644
--- a/arch/sparc64/kernel/kstack.h
+++ b/arch/sparc64/kernel/kstack.h
@@ -15,15 +15,16 @@ static inline bool kstack_valid(struct thread_info *tp, unsigned long sp)
             sp <= (base + THREAD_SIZE - sizeof(struct sparc_stackf)))
                 return true;
 
-        base = (unsigned long) hardirq_stack[tp->cpu];
-        if (sp >= base &&
-            sp <= (base + THREAD_SIZE - sizeof(struct sparc_stackf)))
-                return true;
-        base = (unsigned long) softirq_stack[tp->cpu];
-        if (sp >= base &&
-            sp <= (base + THREAD_SIZE - sizeof(struct sparc_stackf)))
-                return true;
-
+        if (hardirq_stack[tp->cpu]) {
+                base = (unsigned long) hardirq_stack[tp->cpu];
+                if (sp >= base &&
+                    sp <= (base + THREAD_SIZE - sizeof(struct sparc_stackf)))
+                        return true;
+                base = (unsigned long) softirq_stack[tp->cpu];
+                if (sp >= base &&
+                    sp <= (base + THREAD_SIZE - sizeof(struct sparc_stackf)))
+                        return true;
+        }
         return false;
 }
 
@@ -37,15 +38,16 @@ static inline bool kstack_is_trap_frame(struct thread_info *tp, struct pt_regs *
             addr <= (base + THREAD_SIZE - sizeof(*regs)))
                 goto check_magic;
 
-        base = (unsigned long) hardirq_stack[tp->cpu];
-        if (addr >= base &&
-            addr <= (base + THREAD_SIZE - sizeof(*regs)))
-                goto check_magic;
-        base = (unsigned long) softirq_stack[tp->cpu];
-        if (addr >= base &&
-            addr <= (base + THREAD_SIZE - sizeof(*regs)))
-                goto check_magic;
-
+        if (hardirq_stack[tp->cpu]) {
+                base = (unsigned long) hardirq_stack[tp->cpu];
+                if (addr >= base &&
+                    addr <= (base + THREAD_SIZE - sizeof(*regs)))
+                        goto check_magic;
+                base = (unsigned long) softirq_stack[tp->cpu];
+                if (addr >= base &&
+                    addr <= (base + THREAD_SIZE - sizeof(*regs)))
+                        goto check_magic;
+        }
         return false;
 
 check_magic:
diff --git a/arch/sparc64/kernel/stacktrace.c b/arch/sparc64/kernel/stacktrace.c
index 237e7f8a40ac..4e21d4a57d3b 100644
--- a/arch/sparc64/kernel/stacktrace.c
+++ b/arch/sparc64/kernel/stacktrace.c
@@ -9,8 +9,8 @@
 
 void save_stack_trace(struct stack_trace *trace)
 {
-        unsigned long ksp, fp, thread_base;
         struct thread_info *tp = task_thread_info(current);
+        unsigned long ksp, fp;
 
         stack_trace_flush();
 
@@ -20,7 +20,6 @@ void save_stack_trace(struct stack_trace *trace)
         );
 
         fp = ksp + STACK_BIAS;
-        thread_base = (unsigned long) tp;
         do {
                 struct sparc_stackf *sf;
                 struct pt_regs *regs;