There's a bug here that will need a small change to the entry code. Mike Galbraith reported: WARNING: can't dereference registers at ffffc900089d7e08 for ip ffffffff81740bbb After some looking I found that it's caused by the following code snippet in the 'interrupt' macro in entry_64.S: /* * Save previous stack pointer, optionally switch to interrupt stack. * irq_count is used to check if a CPU is already on an interrupt stack * or not. While this is essentially redundant with preempt_count it is * a little cheaper to use a separate counter in the PDA (short of * moving irq_enter into assembly, which would be too much work) */ movq %rsp, %rdi incl PER_CPU_VAR(irq_count) cmovzq PER_CPU_VAR(irq_stack_ptr), %rsp UNWIND_HINT_REGS base=rdi pushq %rdi UNWIND_HINT_REGS indirect=1 The problem is that it's changing the stack pointer *before* writing the previous stack pointer (push %rdi). So when unwinding from an NMI which hit between the rsp write and the rdi push, the unwinder tries to access the regs on the previous stack (by reading rdi), but the previous stack pointer isn't there yet, so the access is considered out of bounds. -- Josh -- To unsubscribe from this list: send the line "unsubscribe live-patching" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
