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iommu: Check if group is NULL before remove device 

[ Upstream commit 5aa95d8834e07907e64937d792c12ffef7fb271f ]

If probe_device is failing, iommu_group is not initialized because
iommu_group_add_device is not reached, so freeing it will result
in NULL pointer access.

iommu_bus_init
  ->bus_iommu_probe
      ->probe_iommu_group in for each:/* return -22 in fail case */
          ->iommu_probe_device
              ->__iommu_probe_device       /* return -22 here.*/
                  -> ops->probe_device          /* return -22 here.*/
                  -> iommu_group_get_for_dev
                        -> ops->device_group
                        -> iommu_group_add_device //good case
  ->remove_iommu_group  //in fail case, it will remove group
     ->iommu_release_device
         ->iommu_group_remove_device // here we don't have group

In my case ops->probe_device (mtk_iommu_probe_device from
mtk_iommu_v1.c) is due to failing fwspec->ops mismatch.

Fixes: d72e31c937 ("iommu: IOMMU Groups")
Signed-off-by: Frank Wunderlich <frank-w@public-files.de>
Link: https://lore.kernel.org/r/20210731074737.4573-1-linux@fw-web.de
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Frank Wunderlich 2021-07-31 09:47:37 +02:00 committed by Sasha Levin
parent 911a8141ef
commit cb9a9d5fe6
1 changed files with 3 additions and 0 deletions
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3
drivers/iommu/iommu.c
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@ -775,6 +775,9 @@ void iommu_group_remove_device(struct device *dev)
struct iommu_group *group = dev->iommu_group;
struct group_device *tmp_device, *device = NULL;
if (!group)
return;
dev_info(dev, "Removing from iommu group %d\n", group->id);
/* Pre-notify listeners that a device is being removed. */