From: Geert Uytterhoeven <geert+rene...@glider.be>

[ Upstream commit e5b78f2e349eef5d4fca5dc1cf5a3b4b2cc27abd ]

If iommu_ops.add_device() fails, iommu_ops.domain_free() is still
called, leading to a crash, as the domain was only partially
initialized:

    ipmmu-vmsa e67b0000.mmu: Cannot accommodate DMA translation for IOMMU page 
tables
    sata_rcar ee300000.sata: Unable to initialize IPMMU context
    iommu: Failed to add device ee300000.sata to group 0: -22
    Unable to handle kernel NULL pointer dereference at virtual address 
0000000000000038
    ...
    Call trace:
     ipmmu_domain_free+0x1c/0xa0
     iommu_group_release+0x48/0x68
     kobject_put+0x74/0xe8
     kobject_del.part.0+0x3c/0x50
     kobject_put+0x60/0xe8
     iommu_group_get_for_dev+0xa8/0x1f0
     ipmmu_add_device+0x1c/0x40
     of_iommu_configure+0x118/0x190

Fix this by checking if the domain's context already exists, before
trying to destroy it.

Signed-off-by: Geert Uytterhoeven <geert+rene...@glider.be>
Reviewed-by: Robin Murphy <robin.mur...@arm.com>
Fixes: d25a2a16f0889 ('iommu: Add driver for Renesas VMSA-compatible IPMMU')
Signed-off-by: Joerg Roedel <jroe...@suse.de>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 drivers/iommu/ipmmu-vmsa.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/iommu/ipmmu-vmsa.c b/drivers/iommu/ipmmu-vmsa.c
index 624e7ff76166..9101be1a6b59 100644
--- a/drivers/iommu/ipmmu-vmsa.c
+++ b/drivers/iommu/ipmmu-vmsa.c
@@ -372,6 +372,9 @@ static int ipmmu_domain_init_context(struct 
ipmmu_vmsa_domain *domain)
 
 static void ipmmu_domain_destroy_context(struct ipmmu_vmsa_domain *domain)
 {
+       if (!domain->mmu)
+               return;
+
        /*
         * Disable the context. Flush the TLB as required when modifying the
         * context registers.
-- 
2.17.1

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