Blackfin: make sure stack is accessible before dumping it

When displaying a crash dump, make sure accessing the stack is safe so
we don't crash at the same time.

Signed-off-by: Robin Getz <robin.getz@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

diff --git a/arch/blackfin/kernel/traps.c b/arch/blackfin/kernel/traps.c
index fb57742..0d04a47 100644 (file)
--- a/arch/blackfin/kernel/traps.c
+++ b/arch/blackfin/kernel/traps.c
@@ -196,6 +196,11 @@ done:
 
 asmlinkage void double_fault_c(struct pt_regs *fp)
 {
+#ifdef CONFIG_DEBUG_BFIN_HWTRACE_ON
+       int j;
+       trace_buffer_save(j);
+#endif
+
        console_verbose();
        oops_in_progress = 1;
 #ifdef CONFIG_DEBUG_VERBOSE
@@ -220,6 +225,7 @@ asmlinkage void double_fault_c(struct pt_regs *fp)
                dump_bfin_process(fp);
                dump_bfin_mem(fp);
                show_regs(fp);
+               dump_bfin_trace_buffer();
        }
 #endif
        panic("Double Fault - unrecoverable event");
@@ -832,6 +838,11 @@ void show_stack(struct task_struct *task, unsigned long *stack)
        decode_address(buf, (unsigned int)stack);
        printk(KERN_NOTICE " SP: [0x%p] %s\n", stack, buf);
 
+       if (!access_ok(VERIFY_READ, stack, (unsigned int)endstack - (unsigned int)stack)) {
+               printk(KERN_NOTICE "Invalid stack pointer\n");
+               return;
+       }
+
        /* First thing is to look for a frame pointer */
        for (addr = (unsigned int *)((unsigned int)stack & ~0xF); addr < endstack; addr++) {
                if (*addr & 0x1)