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Subject: Re: [PATCH 1/1] ppc64: fix missing to check all bits of
 _TIF_USER_WORK_MASK in preempt
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: "tiejun.chen" <tiejun.chen@windriver.com>
Date: Tue, 13 Dec 2011 16:55:09 +1100
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On Tue, 2011-12-13 at 13:01 +0800, tiejun.chen wrote:
> Tiejun Chen wrote:
> > In entry_64.S version of ret_from_except_lite, you'll notice that
> > in the !preempt case, after we've checked MSR_PR we test for any
> > TIF flag in _TIF_USER_WORK_MASK to decide whether to go to do_work
> > or not. However, in the preempt case, we do a convoluted trick to
> > test SIGPENDING only if PR was set and always test NEED_RESCHED ...
> > but we forget to test any other bit of _TIF_USER_WORK_MASK !!! So
> > that means that with preempt, we completely fail to test for things
> > like single step, syscall tracing, etc...
> > 
> > This should be fixed as the following path:
> > 
> >  - Test PR. If set, go to test_work_user, else continue.
> > 
> >  - In test_work_user, always test for _TIF_USER_WORK_MASK to decide to
> > go to do_work, maybe call it do_user_work
> > 
> >  - In test_work_kernel, test for _TIF_KERNEL_WORK_MASK which is set to
> > our new flag along with NEED_RESCHED if preempt is enabled and branch to
> > do_kernel_work.
> 
> Ben,
> 
> Any comment for this?

Sorry, I didn't get to review that one yet (nor reply to your newer
responses), I have very sore eyes and basically had to get off the
computer. Hopefully I'll be better tomorrow.

Cheers,
Ben.