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Date: Fri, 7 Oct 2011 17:09:17 +0200
From: Andi Kleen <andi@firstfloor.org>
To: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Stephane Eranian <eranian@google.com>, Andi Kleen <andi@firstfloor.org>,
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Subject: Re: [PATCH 07/12] perf_events: add LBR software filter support for Intel X86
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> if (kernel_ip(addr) || !test_tsk_thread_flag(current, TIF_IA32))

That's not good, a 64bit process can do 32bit syscalls.

The only fully working way is to check the code segment, unfortunately
that requires checking the LDT to be fully correct :-(

In 2.4 we had some code for that if you want to copy, but it disappeared
later.

-Andi
-- 
ak@linux.intel.com -- Speaking for myself only.