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    SubjectRe: [PATCH 4.19 241/422] net: socionext: Fix two sleep-in-atomic-context bugs in ave_rxfifo_reset()
    Hi!

    > [ Upstream commit 0020f5c807ef67954d9210eea0ba17a6134cdf7d ]
    >
    > The driver may sleep with holding a spinlock.
    > The function call paths (from bottom to top) in Linux-4.17 are:
    >
    > [FUNC] usleep_range
    > drivers/net/ethernet/socionext/sni_ave.c, 892:
    > usleep_range in ave_rxfifo_reset
    > drivers/net/ethernet/socionext/sni_ave.c, 932:
    > ave_rxfifo_reset in ave_irq_handler
    >
    > [FUNC] usleep_range
    > drivers/net/ethernet/socionext/sni_ave.c, 888:
    > usleep_range in ave_rxfifo_reset
    > drivers/net/ethernet/socionext/sni_ave.c, 932:
    > ave_rxfifo_reset in ave_irq_handler
    >
    > To fix these bugs, usleep_range() is replaced with udelay().

    I don't believe this is serious enough for -stable, but more
    importantly:

    > +++ b/drivers/net/ethernet/socionext/sni_ave.c
    > @@ -906,11 +906,11 @@ static void ave_rxfifo_reset(struct net_device *ndev)
    >
    > /* assert reset */
    > writel(AVE_GRR_RXFFR, priv->base + AVE_GRR);
    > - usleep_range(40, 50);
    > + udelay(50);
    >
    > /* negate reset */
    > writel(0, priv->base + AVE_GRR);
    > - usleep_range(10, 20);
    > + udelay(20);
    >

    udelay(40) / udelay(10) should be enough here.

    Best regards,
    Pavel
    --
    (english) http://www.livejournal.com/~pavelmachek
    (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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