From: "Alexander Beregalov" <[EMAIL PROTECTED]>
Date: Mon, 7 Jul 2008 19:59:04 +0400

> I have turned off LOCKDEP and it boots properly.
> 2.6.26-rc9-00005-g1b40a89
> 
> Mikael's config also does not contain LOCKDEP.

I have finally reproduced the problem locally and figured out the
bug.

Please try this patch:

sparc64: Fix end-of-stack checking in save_stack_trace().

Bug reported by Alexander Beregalov.

Before we dereference the stack frame or try to peek at the
pt_regs magic value, make sure the entire object is within
the kernel stack bounds.

Signed-off-by: David S. Miller <[EMAIL PROTECTED]>

diff --git a/arch/sparc64/kernel/stacktrace.c b/arch/sparc64/kernel/stacktrace.c
index c73ce3f..c5576e8 100644
--- a/arch/sparc64/kernel/stacktrace.c
+++ b/arch/sparc64/kernel/stacktrace.c
@@ -25,13 +25,15 @@ void save_stack_trace(struct stack_trace *trace)
 
                /* Bogus frame pointer? */
                if (fp < (thread_base + sizeof(struct thread_info)) ||
-                   fp >= (thread_base + THREAD_SIZE))
+                   fp > (thread_base + THREAD_SIZE - sizeof(struct 
sparc_stackf)))
                        break;
 
                sf = (struct sparc_stackf *) fp;
                regs = (struct pt_regs *) (sf + 1);
 
-               if ((regs->magic & ~0x1ff) == PT_REGS_MAGIC) {
+               if (((unsigned long)regs <=
+                    (thread_base + THREAD_SIZE - sizeof(*regs))) &&
+                   (regs->magic & ~0x1ff) == PT_REGS_MAGIC) {
                        if (!(regs->tstate & TSTATE_PRIV))
                                break;
                        pc = regs->tpc;
--
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