[PATCH AUTOSEL 5.14 02/21] habanalabs: fix nullifying of destroyed mmu pgt pool

From: Sasha Levin
Date: Thu Sep 16 2021 - 22:33:42 EST


From: Tomer Tayar <ttayar@xxxxxxxxx>

[ 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@xxxxxxxxx>
Reviewed-by: Oded Gabbay <ogabbay@xxxxxxxxxx>
Signed-off-by: Oded Gabbay <ogabbay@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/misc/habanalabs/common/mmu/mmu_v1.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/misc/habanalabs/common/mmu/mmu_v1.c b/drivers/misc/habanalabs/common/mmu/mmu_v1.c
index c5e93ff32586..0f536f79dd9c 100644
--- a/drivers/misc/habanalabs/common/mmu/mmu_v1.c
+++ b/drivers/misc/habanalabs/common/mmu/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;
+ }
}

/**
--
2.30.2