On 04-12-14 11:19, Jeremiah Mahler wrote: > Arend, > > I haven't heard if you have looked at this bug at all yet. I was > curious so I looked at it some more and I have some more information > that might be helpful. > > On Wed, Dec 03, 2014 at 01:41:28PM -0800, Jeremiah Mahler wrote: >> On Wed, Dec 03, 2014 at 01:06:59PM -0800, Jeremiah Mahler wrote: >>> Arend, >>> > [...] >>>>> >>>>> I took a look at the patch that is causing this problem (d32394fae95). >>>>> My config negates everything in the patch except for a one line change >>>>> to ath9k/pci.c. If I remove this change (shown below) the problem goes >>>>> away. >>>> >>>> Ok. But then it will likely crash when you cat one of the changed debugfs >>>> files. Guess this commit needs to be reverted entirely. >>>> > [...] > > Referring to the code snippet below, notice that both pci_set_drvdata() > and dev_set_drvdata() are called. If the call to dev_set_drvdata() is > removed the bug goes away. > > drivers/net/wireless/ath/ath9k/pci.c > > 861 SET_IEEE80211_DEV(hw, &pdev->dev); > 862 pci_set_drvdata(pdev, hw); > 863 > 864 sc = hw->priv; > 865 sc->hw = hw; > 866 sc->dev = &pdev->dev; > 867 dev_set_drvdata(sc->dev, sc); > 868 sc->mem = pcim_iomap_table(pdev)[0]; > 869 sc->driver_data = id->driver_data; > > Translating the call to pci_set_drvdata() produces the following. > > pci_set_drvdata(pdev, hw); > (translating from include/linux/pci.h) > dev_set_drvdata(&pdev->dev, hw) > (translating from include/linux/device.h) > &pdev->dev->driver = hw; > > And doing the same for dev_set_drvdata(). > > dev_set_drvdata(sc->dev, sc) > (sc->dev = &pdev->dev) > dev_set_drvdata(&pdev->dev, sc) > (translating from include/linux/device.h) > &pdev->dev->driver = sc; > > The same destination is being set with two different values. Then calls > to pci_get_drvdata(), which expect hw, are getting sc, and it breaks.
Yes, that was my suspicion as well. This is why I asked to revert the patch entirely. I see that sc equals hw->priv so I know how to correct it. However, with merge window around the corner it may be easier to do a revert. Regards, Arend -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
