Re: [PATCH 1/5] signal(x86_32): Improve the signal stack overflowcheck

From: Ingo Molnar
Date: Wed Feb 20 2008 - 05:28:00 EST



* Roland McGrath <roland@xxxxxxxxxx> wrote:

> > I spent some time read you mail carefully and dig into the code again.
> >
> > And yes, you are right. It's possible that SA_ONSTACK has been cleared
> > before the second signal on the same stack comes.
>
> It's not necessary for SA_ONSTACK to have "been cleared", by which I
> assume you mean a sigaction call with SA_ONSTACK not set in sa_flags.
> That is indeed possible, but it's not the only case your patch broke.
> It can just be a different signal whose sigaction never had
> SA_ONSTACK, when you are still on the signal stack from an earlier
> signal that did have SA_ONSTACK.
>
> > So this patch is wrong :( . I will revise the other 4 patches.
>
> For 2 and 3, I would rather just wait until we unify signal.c anyway.

ok, i've removed these patches from x86.git#testing for now:

Subject: x86: improve the signal stack overflow logic, 32-bit
Subject: x86: add a signal stack overflow check, 64-bit
Subject: x86: add signal stack overflow check, 32-bit

and will wait for a resubmission and an Ack from Roland.

Ingo
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