[PATCH] x86: Terminate the kernel stacks for the unwinder
Always make sure RIP/EIP is 0 in the registers stored on the top
of the stack of a kernel thread. This makes sure the unwinder code
won't try a fallback but knows the stack has ended.
AK: this patch is a bit mysterious. in theory they should be terminated
anyways, but it seems to fix at least one crash. Anyways double termination
probably doesn't hurt.
Signed-off-by: Andi Kleen <ak@suse.de>
diff --git a/arch/x86_64/kernel/entry.S b/arch/x86_64/kernel/entry.S
index b8285cf..ab9b2c4 100644
--- a/arch/x86_64/kernel/entry.S
+++ b/arch/x86_64/kernel/entry.S
@@ -978,6 +978,11 @@
call do_fork
movq %rax,RAX(%rsp)
xorl %edi,%edi
+ test %rax,%rax
+ jnz 1f
+ /* terminate stack in child */
+ movq %rdi,RIP(%rsp)
+1:
/*
* It isn't worth to check for reschedule here,