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SubjectRe: mcs7830 usb net: "scheduling while atomic" danger?
On Mon, 18 Jan 2010, Andreas Mohr wrote:

> Hi,
>
> drivers/net/usb/mcs7830.c does several:
>
> mutex_lock(&dev->phy_mutex);
> /* write the MII command */
> ret = mcs7830_set_reg(dev, HIF_REG_PHY_CMD1, 2, cmd);
> if (ret < 0)
> goto out;
>
> /* wait for the data to become valid, should be within < 1ms */
> for (i = 0; i < 10; i++) {
> ret = mcs7830_get_reg(dev, HIF_REG_PHY_CMD1, 2, cmd);
> if ((ret < 0) || (cmd[1] &
> HIF_REG_PHY_CMD2_READY_FLAG_BIT))
> break;
> ret = -EIO;
> msleep(1);
> }
>
>
> Forgive me, but doesn't that mutex_lock()/msleep() (ab)use mean
> risking a "scheduling while atomic"?
> (such as discussed in e.g.
> http://search.luky.org/linux-kernel.2004/msg92817.html )
>
>
> And, if that is the case, shouldn't all such cases simply be killed for
> good via a capable semantic patch?

This could easily be done, if the diagnosis is correct.

julia


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