habanalabs: fix nullifying of destroyed mmu pgt pool

BugLink: https://bugs.launchpad.net/bugs/1949397
[ Upstream commit 89aad770d692e4d2d9a604c1674e9dfa69421430 ]

In case of host-resident MMU, when the page tables pool is destroyed,
its pointer is not nullified correctly.
As a result, on a device fini which happens after a failing reset, the
already destroyed pool is accessed, which leads to a kernel panic.
The patch fixes the setting of the pool pointer to NULL.

Signed-off-by: Tomer Tayar <ttayar@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Kelsey Skunberg <kelsey.skunberg@canonical.com>

diff --git a/drivers/misc/habanalabs/common/mmu_v1.c b/drivers/misc/habanalabs/common/mmu_v1.c
index 06d8a44dd5d428e0bfdbb12a5571afef8c7163c8..a5be1c096e390818883e3fd0170cdf28e607aef4 100644 (file)
--- a/drivers/misc/habanalabs/common/mmu_v1.c
+++ b/drivers/misc/habanalabs/common/mmu_v1.c
@@ -470,13 +470,13 @@ static void hl_mmu_v1_fini(struct hl_device *hdev)
        if (!ZERO_OR_NULL_PTR(hdev->mmu_priv.hr.mmu_shadow_hop0)) {
                kvfree(hdev->mmu_priv.dr.mmu_shadow_hop0);
                gen_pool_destroy(hdev->mmu_priv.dr.mmu_pgt_pool);
-       }
 
-       /* Make sure that if we arrive here again without init was called we
-        * won't cause kernel panic. This can happen for example if we fail
-        * during hard reset code at certain points
-        */
-       hdev->mmu_priv.dr.mmu_shadow_hop0 = NULL;
+               /* Make sure that if we arrive here again without init was
+                * called we won't cause kernel panic. This can happen for
+                * example if we fail during hard reset code at certain points
+                */
+               hdev->mmu_priv.dr.mmu_shadow_hop0 = NULL;
+       }
 }
 
 /**