linux-kernel - Re: [PATCH 00/11] ARMv8.3 pointer authentication userspace support

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Message-ID: <bb507ee1-c7ba-4c73-0d0f-058c4821793c@arm.com>
Date:   Tue, 25 Jul 2017 12:32:10 +0100
From:   Yao Qi <yao.qi@....com>
To:     Mark Rutland <mark.rutland@....com>,
        linux-arm-kernel@...ts.infradead.org
Cc:     arnd@...db.de, catalin.marinas@....com,
        christoffer.dall@...aro.org, Dave.Martin@....com,
        jiong.wang@....com, kvmarm@...ts.cs.columbia.edu,
        linux-arch@...r.kernel.org, marc.zyngier@....com,
        suzuki.poulose@....com, will.deacon@....com,
        linux-kernel@...r.kernel.org, kernel-hardening@...ts.openwall.com
Subject: Re: [PATCH 00/11] ARMv8.3 pointer authentication userspace support

On 19/07/17 17:01, Mark Rutland wrote:
> If authentication fails, bits are set in the pointer such that it is guaranteed
> to cause a fault if used.

How does user space know the fault is caused by authentication fail?
When GDB is debugging a program, and it failed in pointer
authentication, I assume GDB only knows that the program receives signal
SIGSEGV, but how does GDB or user know why does the program get SIGSEGV?
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