6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Gyeyoung Baek [ Upstream commit 196d4d10c1b33ae176685ff42a9994a5952b1d0f ] When a map overlaps part of an existing mapping, pvr_vm_gpuva_remap() splits the mapping into prev/next parts covering what the request did not take, instead of creating something new. It gets two things wrong. - A GEM reference is taken for each part but it's never needed and never dropped, so it leaks one reference per split (remap-next-in-2m in tests/imagination/pvr_vm_map.c): CRITICAL: 33558528 bytes of shmem still held after close - The parts still belong to the original object being split, but pvr_vm_gpuva_remap() links them to ctx->gpuvm_bo, the new object's vm_bo: prev_va --obj--> BO_A BO_B <--obj-- vm_bo (ctx->gpuvm_bo) \___________link___________/ (mismatch: BO_A != BO_B) drm_gpuva_link() catches the mismatch: WARNING: drivers/gpu/drm/drm_gpuvm.c:2108 at drm_gpuva_link+0x2ec/0x310 drm_WARN_ON(obj != vm_bo->obj) Call trace: drm_gpuva_link pvr_vm_gpuva_remap __drm_gpuvm_sm_map pvr_vm_map pvr_ioctl_vm_map Link them to op->remap.unmap->va->vm_bo instead. The locking of the GPUVA lists of the other objects touched by a split is not addressed here; it is handled by switching the GPUVM to immediate mode. Fixes: ff5f643de0bf ("drm/imagination: Add GEM and VM related code") Signed-off-by: Gyeyoung Baek Reviewed-by: Brajesh Gupta Link: https://patch.msgid.link/20261001-pvr-fixes-a-v2-1-f58254e5dfb8@gmail.com Signed-off-by: Alessio Belle Signed-off-by: Sasha Levin --- drivers/gpu/drm/imagination/pvr_vm.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/imagination/pvr_vm.c b/drivers/gpu/drm/imagination/pvr_vm.c index e59b93c1a6e1a..bc699b600de1c 100644 --- a/drivers/gpu/drm/imagination/pvr_vm.c +++ b/drivers/gpu/drm/imagination/pvr_vm.c @@ -417,6 +417,8 @@ pvr_vm_gpuva_unmap(struct drm_gpuva_op *op, void *op_ctx) static int pvr_vm_gpuva_remap(struct drm_gpuva_op *op, void *op_ctx) { + /* The split parts belong to the object of the mapping being split. */ + struct drm_gpuvm_bo *vm_bo = op->remap.unmap->va->vm_bo; struct pvr_vm_bind_op *ctx = op_ctx; u64 va_start = 0, va_range = 0; int err; @@ -432,14 +434,12 @@ pvr_vm_gpuva_remap(struct drm_gpuva_op *op, void *op_ctx) drm_gpuva_remap(&ctx->prev_va->base, &ctx->next_va->base, &op->remap); if (op->remap.prev) { - pvr_gem_object_get(gem_to_pvr_gem(ctx->prev_va->base.gem.obj)); - drm_gpuva_link(&ctx->prev_va->base, ctx->gpuvm_bo); + drm_gpuva_link(&ctx->prev_va->base, vm_bo); ctx->prev_va = NULL; } if (op->remap.next) { - pvr_gem_object_get(gem_to_pvr_gem(ctx->next_va->base.gem.obj)); - drm_gpuva_link(&ctx->next_va->base, ctx->gpuvm_bo); + drm_gpuva_link(&ctx->next_va->base, vm_bo); ctx->next_va = NULL; } -- 2.53.0