On Wed, 2017-02-15 at 16:42 +0200, Andy Shevchenko wrote: > By default CONFIG_INTEL_IOMMU_DEFAULT_ON is not set and thus > dmar_disabled variable is set. > > Intel IOMMU driver based on above doesn't set intel_iommu_enabled > variable. > > The commit b0119e870837 ("iommu: Introduce new 'struct iommu_device'") > mistakenly assumes it never happens and tries to unregister not ever > registered resources, which crashes the kernel at boot time: > > BUG: unable to handle kernel NULL pointer dereference at > 0000000000000008 > IP: iommu_device_unregister+0x31/0x60 > > Make unregister procedure conditional in free_iommu().
Joerg, it looks like bug is still present. Can we get the fix merged? Or do you have better ideas? > > Fixes: b0119e870837 ("iommu: Introduce new 'struct iommu_device'") > Cc: Joerg Roedel <jroe...@suse.de> > Signed-off-by: Andy Shevchenko <andriy.shevche...@linux.intel.com> > --- > drivers/iommu/dmar.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c > index d9c0decfc91a..36e3f430d265 100644 > --- a/drivers/iommu/dmar.c > +++ b/drivers/iommu/dmar.c > @@ -1108,8 +1108,10 @@ static int alloc_iommu(struct dmar_drhd_unit > *drhd) > > static void free_iommu(struct intel_iommu *iommu) > { > - iommu_device_sysfs_remove(&iommu->iommu); > - iommu_device_unregister(&iommu->iommu); > + if (intel_iommu_enabled) { > + iommu_device_unregister(&iommu->iommu); > + iommu_device_sysfs_remove(&iommu->iommu); > + } > > if (iommu->irq) { > if (iommu->pr_irq) { -- Andy Shevchenko <andriy.shevche...@linux.intel.com> Intel Finland Oy _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu