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Date: Thu, 25 Mar 2021 22:27:33 +0100
From: Borislav Petkov <bp@suse.de>
To: "Bae, Chang Seok" <chang.seok.bae@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>,
 "Cooper, Andrew" <andrew.cooper3@citrix.com>,
 Boris Ostrovsky <boris.ostrovsky@oracle.com>,
 "Gross, Jurgen" <jgross@suse.com>,
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 Thomas Gleixner <tglx@linutronix.de>,
 Ingo Molnar <mingo@kernel.org>, X86 ML <x86@kernel.org>,
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 "H. J. Lu" <hjl.tools@gmail.com>, Dave Martin <Dave.Martin@arm.com>,
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Subject: Re: [PATCH v7 5/6] x86/signal: Detect and prevent an alternate
 signal stack overflow
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On Thu, Mar 25, 2021 at 09:11:56PM +0000, Bae, Chang Seok wrote:
> But if sigaltstack()’ed with the SS_AUTODISARM flag, both on_sig_stack() and
> sas_ss_flags() return 0 [1]. Then, segfault always here. v5 had the exact
> issue before [2].

Ah, there's that SS_AUTODISARM check above it which I missed, sorry.

I guess we can do a __on_sig_stack() helper or so which does the stack
check only without the SS_AUTODISARM. Just for readability's sake in
what is already a pretty messy function.

Thx.

-- 
Regards/Gruss,
    Boris.

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