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Date: Tue, 5 Jul 2005 16:16:51 +0200
From: Andi Kleen <ak@suse.de>
To: Roland McGrath <roland@redhat.com>, Andrew Morton <akpm@osdl.org>,
       Linus Torvalds <torvalds@osdl.org>, Andi Kleen <ak@suse.de>,
       linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86-64: ptrace ia32 BP fix
Message-ID: <20050705141651.GW21330@wotan.suse.de>
References: <200507050931.j659VFEa028271@magilla.sf.frob.com> <20050705140724.GA19552@nevyn.them.org>
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> Wouldn't this  to botch a debugger which supported both backtracing and
> PTRACE_SYSCALL, when stopped in a syscall?  We have unwind information
> for the VDSO and it's not going to tell us that the kernel has done
> something clever to the value of %ebp.

The kernel is indeed not supposed to modify any input
registers of syscalls (ok except rcx, but that is unavoidable)

-Andi