linux-kernel - Re: [4.1.x -- 4.6.x and probably HEAD] Reproducible unprivileged panic/TLB BUG on sparc via a stack-protected rt_sigaction() ka_restorer, courtesy of the glibc testsuite

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Date:	Mon, 30 May 2016 13:43:01 +0100
From:	Nix <nix@...eri.org.uk>
To:	David Miller <davem@...emloft.net>
Cc:	linux-kernel@...r.kernel.org, sparclinux@...r.kernel.org,
	fweimer@...hat.com
Subject: Re: [4.1.x -- 4.6.x and probably HEAD] Reproducible unprivileged panic/TLB BUG on sparc via a stack-protected rt_sigaction() ka_restorer, courtesy of the glibc testsuite

On 29 May 2016, David Miller spake thusly:

> BTW Nick, in thinking through all of this, I want to strongly encourage
> you to disable stack protector for all sigreturn stubs in the GLIBC tree.

I completely concur, and have already written (but not committed) a
patch to do this: I'll augment the existing sparc-only patch into a
sigreturn-stubs patch. I *think* I spotted all the stubs. (Many of them
are in assembler, but not all.)

(If there's anything else which involves calling functions with a
precisely-aligned stack and an expectation of no stack pointer movement
in the prologue or epilogue, I'd be interested to know about it, since
that'll need inhibit_stack_protector'ing too.)

-- 
NULL && (void)