Messages in this thread | | | From | Andy Lutomirski <> | Date | Mon, 29 Feb 2016 10:55:40 -0800 | Subject | Re: [PATCH 00/10] x86: Various SYSENTER/SYSEXIT/#DB fixes and cleanups |
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On Sun, Feb 28, 2016 at 9:28 PM, Andy Lutomirski <luto@kernel.org> wrote: > > While I was doing all this, I also noticed that DR6 and BTF handling > in do_debug was a bit off. Two of the patches in here try to fix it > up.
It's worth noting that do_debug is really quite screwed up with or without this patchset applied. For example:
/* * Let others (NMI) know that the debug stack is in use * as we may switch to the interrupt stack. */ debug_stack_usage_inc();
/* It's safe to allow irq's after DR6 has been saved */ preempt_disable(); cond_local_irq_enable(regs);
This has never really been valid. It should be guarded by an if(user_mode(regs)). And we need to kill the die_notifier garbage in here -- it makes it basically impossible to understand what's going on.
--Andy
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