On 21/10/2025 09:10, Akash Goel wrote:
> This commit addresses a memleak issue of panthor_vma (or drm_gpuva)
> structure in Panthor driver, that can happen if the GPU page table
> update operation to map the pages fail.
> The issue is very unlikely to occur in practice.
>
> v2: Add panthor_vm_op_ctx_return_vma() helper (Boris)
>
> v3: Add WARN_ON_ONCE (Boris)
>
> Fixes: 647810ec2476 ("drm/panthor: Add the MMU/VM logical block")
> Signed-off-by: Akash Goel <[email protected]>
> Reviewed-by: Boris Brezillon <[email protected]>
Reviewed-by: Steven Price <[email protected]>
> ---
> drivers/gpu/drm/panthor/panthor_mmu.c | 18 +++++++++++++++++-
> 1 file changed, 17 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c
> b/drivers/gpu/drm/panthor/panthor_mmu.c
> index 6dec4354e378..56a53d70f3b2 100644
> --- a/drivers/gpu/drm/panthor/panthor_mmu.c
> +++ b/drivers/gpu/drm/panthor/panthor_mmu.c
> @@ -1146,6 +1146,20 @@ static void panthor_vm_cleanup_op_ctx(struct
> panthor_vm_op_ctx *op_ctx,
> }
> }
>
> +static void
> +panthor_vm_op_ctx_return_vma(struct panthor_vm_op_ctx *op_ctx,
> + struct panthor_vma *vma)
> +{
> + for (u32 i = 0; i < ARRAY_SIZE(op_ctx->preallocated_vmas); i++) {
> + if (!op_ctx->preallocated_vmas[i]) {
> + op_ctx->preallocated_vmas[i] = vma;
> + return;
> + }
> + }
> +
> + WARN_ON_ONCE(1);
> +}
> +
> static struct panthor_vma *
> panthor_vm_op_ctx_get_vma(struct panthor_vm_op_ctx *op_ctx)
> {
> @@ -2081,8 +2095,10 @@ static int panthor_gpuva_sm_step_map(struct
> drm_gpuva_op *op, void *priv)
> ret = panthor_vm_map_pages(vm, op->map.va.addr,
> flags_to_prot(vma->flags),
> op_ctx->map.sgt, op->map.gem.offset,
> op->map.va.range);
> - if (ret)
> + if (ret) {
> + panthor_vm_op_ctx_return_vma(op_ctx, vma);
> return ret;
> + }
>
> /* Ref owned by the mapping now, clear the obj field so we don't
> release the
> * pinning/obj ref behind GPUVA's back.
