From: Luca Barbieri <ldb@ldb.ods.org>
To: Linux-Kernel ML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] (re-xmit): kprobes for i386
Date: 20 Aug 2002 16:06:58 +0200 [thread overview]
Message-ID: <1029852418.8662.267.camel@ldb> (raw)
In-Reply-To: <3D62365E.8030905@iram.es>
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> > Something like this:
> > ENTRY(debug)
> > testl $0x3, 4(%esp)
> > jz handle_kernel_mode_debug
> >
>
> This check is insufficient, it can go the wrong way if the interrupted
> taks is in vm 86 mode (and open a big security hole, I believe).
Right.
This test from ret_from_intr could be used instead:
push %es
push %ds
push %eax
movl 8(%esp), %eax
movb 4(%esp), %al
testl $(VM_MASK | 3), %eax
jz handle_kernel_mode
There is however a potential register stall for the eax read after the
al write.
BTW, vm86 has the VM flag set so the comment in ret_from_intr is wrong.
The code seems to be right though.
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next prev parent reply other threads:[~2002-08-20 14:02 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-08-20 4:39 [PATCH] (re-xmit): kprobes for i386 Rusty Russell
2002-08-20 8:19 ` Christoph Hellwig
2002-08-20 10:25 ` Rusty Russell
2002-08-20 11:54 ` Luca Barbieri
[not found] ` <3D62365E.8030905@iram.es>
2002-08-20 14:06 ` Luca Barbieri [this message]
2002-08-20 19:29 ` Linus Torvalds
2002-08-21 1:03 ` Rusty Russell
2002-08-21 1:29 ` Luca Barbieri
2002-08-21 4:21 ` Rusty Russell
2002-08-21 8:31 ` Vamsi Krishna S .
2002-08-21 10:48 ` Rusty Russell
2002-08-21 12:33 ` Vamsi Krishna S .
-- strict thread matches above, loose matches on Subject: below --
2002-09-20 6:16 [PATCH] Re-xmit: " Rusty Russell
2002-08-12 8:18 [PATCH] (Re-xmit) " Rusty Russell
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