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    SubjectRe: [patch 2.4] make tty->count atomic_t
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    >>>>> "Russell" == Russell King <rmk@arm.linux.org.uk> writes:

    Russell> On Thu, Apr 03, 2003 at 12:16:21PM -0500, Jes Sorensen wrote:
    >> I believe the 2.4 tty code is racey in the way it handles
    >> tty->count. release_dev() does the tty->count-- thing without
    >> protecting against parallel execution, hence tty->count can end up
    >> a random state as
    tty-> count-- isn't guaranteed to be atomic (load-store architectures
    tty-> and
    >> architectures with weak memory ordering etc).

    Russell> Isn't release_dev() only called under the BKL, which
    Russell> guarantees the old "single-thread in the kernel at a time"
    Russell> behaviour from pre-SMP Linux ?

    It's called from tty_release() and tty_open(). tty_release() grabs the
    BKL but I don't see the path that grabs it when calling through
    tty_open() (doesn't mean I am not blind of course ;-).

    cheers,
    Jes
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