[PATCH 5.4 240/411] drm/etnaviv: check for reaped mapping in etnaviv_iommu_unmap_gem

Greg Kroah-Hartman
2022-06-13T11:39:45Z

From: Lucas Stach <l.stach@pengutronix.de>

commit e168c25526cd0368af098095c2ded4a008007e1b upstream.

When the mapping is already reaped the unmap must be a no-op, as we
would otherwise try to remove the mapping twice, corrupting the involved
data structures.

Cc: stable@vger.kernel.org # 5.4
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Tested-by: Guido Günther <agx@sigxcpu.org>
Acked-by: Guido Günther <agx@sigxcpu.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/gpu/drm/etnaviv/etnaviv_mmu.c | 6 ++++++
1 file changed, 6 insertions(+)

--- a/drivers/gpu/drm/etnaviv/etnaviv_mmu.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_mmu.c
@@ -289,6 +289,12 @@ void etnaviv_iommu_unmap_gem(struct etna

mutex_lock(&context->lock);

+ /* Bail if the mapping has been reaped by another thread */
+ if (!mapping->context) {
+ mutex_unlock(&context->lock);
+ return;
+ }
+
/* If the vram node is on the mm, unmap and remove the node */
if (mapping->vram_node.mm == &context->mm)
etnaviv_iommu_remove_mapping(context, mapping);