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    SubjectRe: [CHECKER] large stack variables (>=1K) in 2.4.4 and 2.4.4-ac8
    Andi Kleen wrote:
    > On Fri, May 25, 2001 at 07:52:02AM -0400, Brian Gerst wrote:
    > > Actually, you will never get a stack fault exception, since with a flat
    > > stack segment you can never get a limit violation. All you will do is
    > > corrupt the data in task struct and cause an oops later on when the
    > > kernel tries to use the task struct. There are only two ways to
    > > properly trap a kernel stack overflow:
    > In my experience the stack pointer eventually gets corrupted and starts
    > pointing to some unmapped area, which gives you a stack fault (admittedly
    > a backtrace is a bit hard after that)

    You mean a double fault. #SS is only called when there is a limit
    violation on the stack segment or the stack segment is not present. I
    guess you could get a limit violation if it tried to wrap around below
    0, but you would get a page fault first. An unmapped page will always
    cause a page fault, but since the stack is still invalid, it would then
    cause a double fault.


    Brian Gerst
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