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From: Oleg Nesterov <oleg@redhat.com>
To: Denys Vlasenko <dvlasenk@redhat.com>
Cc: linux-kernel@vger.kernel.org, Jim Keniston <jkenisto@us.ibm.com>,
	Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
	Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
	Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH 1/2] uprobes: add comment with insn opcodes, mnemonics and why we dont support them
Date: Mon, 5 May 2014 21:41:00 +0200	[thread overview]
Message-ID: <20140505194100.GA26916@redhat.com> (raw)
In-Reply-To: <1399314247-7368-1-git-send-email-dvlasenk@redhat.com>

On 05/05, Denys Vlasenko wrote:
>
> + * Opcodes we'll probably never support:
> + * 6c-6f - ins,outs. SEGVs if used in userspace
> + * e4-e7 - in,out imm. SEGVs if used in userspace
> + * ec-ef - in,out acc. SEGVs if used in userspace

Well. I have no idea why they are nacked, but this is not the reason.

SEGVs are fine. Plus we have ioperm().

> + * cc - int3. SIGTRAP if used in userspace

SIGTRAP is not the reason. We do not want to enter do_int3() in UTASK_SSTEP
state with utask->active_uprobe != NULL etc. Too many potential complications.

Oleg.


  parent reply	other threads:[~2014-05-05 19:41 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-05-05 18:24 Denys Vlasenko
2014-05-05 18:24 ` [PATCH 2/2] uprobes: fix 1-byte opcode tables Denys Vlasenko
2014-05-05 19:41 ` Oleg Nesterov [this message]
2014-05-06 17:01   ` [PATCH 1/2] uprobes: add comment with insn opcodes, mnemonics and why we dont support them Denys Vlasenko
2014-05-06 19:26     ` Oleg Nesterov
2014-05-05 22:32 ` Jim Keniston
2014-05-06 16:11   ` Denys Vlasenko

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