Daniel Mack <zon...@gmail.com> writes: > On 23.07.2012 16:47, Alan Stern wrote: >> On Mon, 23 Jul 2012, Sarbojit Ganguly wrote: >>> That is why I provided two stacks, >>> >>> 1st one is when I tried to remove the USB hub (which connects a webcam >>> + microphone) >>> 2nd one is when I tried to remove an USB powered external HDD. >>> >>> Just to make sure whether the problem is with USB sound or the USB >>> subsystem. >> >> Do you stop all the programs that are using the USB devices before >> unplugging the hub? Do you unmount the USB HDD first? >> >> The first crash shows a problem in the snd-usb-audio driver. >> >> The second crash shows a problem in the VFS layer or in ext3, not in >> the USB stack. > > I dare to doubt there are two severe bugs of that kind that are 100% > reproducible. I haven't had a hotplug crash in any of the two drivers > for a long time, and I use both of them extensively.
Actually, based on the recent usb_wwan experience, I'd say that two such bugs isn't as unlikely as it may seem at first. Even three if we add the now fixed usb_wwan (or six, if we count the three drivers affected by the usb_wwan bug). There are probably even more. The reason is this change: 0998d0631 device-core: Ensure drvdata = NULL when no driver is bound It will make bugs like this suddenly 100% reproducible. But the bugs *are* in the drivers, and may have been there for a long time. The drivers have been accessing drvdata after unbinding. They just didn't crash prior to that commit. But the commit is correct, and a very much needed improvement if my assumptions are correct. The drivers need fixing and this just makes it evident. > I rather assume there's something else failing, probably some host > controller issue that corrupts mempory? Can anyone else reproduce this > maybe? You could of course do like me and bisect, but if you end up with commit 0998d0631 then you haven't really learned more than confirming my guess. Bjørn -- 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/
