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Date: Thu, 23 Sep 2010 21:48:56 -0700 (PDT)
Message-Id: <20100923.214856.43029525.davem@davemloft.net>
To: viro@ZenIV.linux.org.uk
Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org,
        sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [GIT] Sparc
From: David Miller <davem@davemloft.net>
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From: Al Viro <viro@ZenIV.linux.org.uk>
Date: Thu, 23 Sep 2010 00:12:19 +0100

> OK... sparc32 question: just what the !@#!@# happens if sun4c_rett_stackchk
> find (%fp & 7) != 0?  We go to ret_trap_user_stack_is_bolixed, which
> tries to page in the underlying page.  OK, suppose it's already there and
> readable; we return without doing anything - and go to signal_p.  Which finds
> itself with nothing to do, and %fp is *still* buggered.  Spin ad infinitum?
> srmmu_rett_stackchk will do the same, BTW...

That's a bug.

Likely all of the window_*_fault() routines should force a SIGILL when
the stack is mis-aligned.