[lkml]   [2003]   [Aug]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: Possible race condition in i386 global_irq_lock handling.
    thanks TeJun,

    just one comment

    On Fri, Aug 22, 2003 at 10:18:40AM +0900, TeJun Huh wrote:
    > 3. remove irqs_running() test from synchronize_irq()

    I'm not convinced this one is needed. An irq can still run on another
    cpu but the cli();sti() may execute while it's here:

    irq running synchronize_irq()
    -------------- -----------------

    irq_enter -> way too late

    in short, doing irqs_running() doesn't seem to weaken the semantics of
    synchronize_irq() to me.

    I think it should be changed this way instead:

    void synchronize_irq(void)
    if (irqs_running()) {
    /* Stupid approach */

    to be sure to read the local irq area after the previous code (the
    test_and_set_bit of the global_irq_lock of a cli() in your version would
    achieve the same implicit smp_mb too, so maybe your only point for doing
    cli()/sti() was to execute the smp_mb before the irqs_running?). the
    above version is more finegrined and it looks equivalent to yours.

    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to
    More majordomo info at
    Please read the FAQ at

     \ /
      Last update: 2005-03-22 13:48    [W:0.034 / U:3.960 seconds]
    ©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site