On Mon, Dec 09, 2019 at 03:12:39PM +0200, mika.westerberg@xxxxxxxxxxxxxxx wrote: > On Mon, Dec 09, 2019 at 12:34:04PM +0000, Nicholas Johnson wrote: > > Hi, > > > > I have compiled Linux v5.5-rc1 and thought all was good until I > > hot-removed a Gigabyte Aorus eGPU from Thunderbolt. The driver for the > > GPU was not loaded (blacklisted) so the crash is nothing to do with the > > GPU driver. > > > > We had: > > - kernel NULL pointer dereference > > - refcount_t: underflow; use-after-free. > > > > Attaching dmesg for now; will bisect and come back with results. > > Looks like something related to iommu. Does it work if you disable it? > (intel_iommu=off in the command line). I thought it could be that, too. The attachment "dmesg-4" from the original email is with iommu parameters. The attachment "dmesg-5" from the original email is with no iommu parameters. Attaching here "dmesg-6" with the iommu explicitly set off like you said. No difference, still broken. Although, with iommu off, there are less stack traces. Could it be sysfs-related? Kind regards, Nicholas
