* [PATCH v2] drm/panthor: Fix potential memleak of vma structure
@ 2025-10-20 20:02 Akash Goel
2025-10-20 21:59 ` Liviu Dudau
2025-10-21 7:41 ` Boris Brezillon
0 siblings, 2 replies; 3+ messages in thread
From: Akash Goel @ 2025-10-20 20:02 UTC (permalink / raw)
To: boris.brezillon, liviu.dudau, steven.price
Cc: dri-devel, linux-kernel, maarten.lankhorst, mripard, tzimmermann,
airlied, daniel, nd, Akash Goel
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)
Fixes: 647810ec2476 ("drm/panthor: Add the MMU/VM logical block")
Signed-off-by: Akash Goel <akash.goel@arm.com>
---
drivers/gpu/drm/panthor/panthor_mmu.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c b/drivers/gpu/drm/panthor/panthor_mmu.c
index 6dec4354e378..63af8ee89b08 100644
--- a/drivers/gpu/drm/panthor/panthor_mmu.c
+++ b/drivers/gpu/drm/panthor/panthor_mmu.c
@@ -1146,6 +1146,18 @@ 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;
+ }
+ }
+}
+
static struct panthor_vma *
panthor_vm_op_ctx_get_vma(struct panthor_vm_op_ctx *op_ctx)
{
@@ -2081,8 +2093,10 @@ 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.
--
2.25.1
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH v2] drm/panthor: Fix potential memleak of vma structure
2025-10-20 20:02 [PATCH v2] drm/panthor: Fix potential memleak of vma structure Akash Goel
@ 2025-10-20 21:59 ` Liviu Dudau
2025-10-21 7:41 ` Boris Brezillon
1 sibling, 0 replies; 3+ messages in thread
From: Liviu Dudau @ 2025-10-20 21:59 UTC (permalink / raw)
To: Akash Goel
Cc: boris.brezillon, steven.price, dri-devel, linux-kernel,
maarten.lankhorst, mripard, tzimmermann, airlied, daniel, nd
On Mon, Oct 20, 2025 at 09:02:43PM +0100, 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)
>
> Fixes: 647810ec2476 ("drm/panthor: Add the MMU/VM logical block")
> Signed-off-by: Akash Goel <akash.goel@arm.com>
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Best regards,
Liviu
> ---
> drivers/gpu/drm/panthor/panthor_mmu.c | 16 +++++++++++++++-
> 1 file changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c b/drivers/gpu/drm/panthor/panthor_mmu.c
> index 6dec4354e378..63af8ee89b08 100644
> --- a/drivers/gpu/drm/panthor/panthor_mmu.c
> +++ b/drivers/gpu/drm/panthor/panthor_mmu.c
> @@ -1146,6 +1146,18 @@ 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;
> + }
> + }
> +}
> +
> static struct panthor_vma *
> panthor_vm_op_ctx_get_vma(struct panthor_vm_op_ctx *op_ctx)
> {
> @@ -2081,8 +2093,10 @@ 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.
> --
> 2.25.1
>
--
====================
| I would like to |
| fix the world, |
| but they're not |
| giving me the |
\ source code! /
---------------
¯\_(ツ)_/¯
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH v2] drm/panthor: Fix potential memleak of vma structure
2025-10-20 20:02 [PATCH v2] drm/panthor: Fix potential memleak of vma structure Akash Goel
2025-10-20 21:59 ` Liviu Dudau
@ 2025-10-21 7:41 ` Boris Brezillon
1 sibling, 0 replies; 3+ messages in thread
From: Boris Brezillon @ 2025-10-21 7:41 UTC (permalink / raw)
To: Akash Goel
Cc: liviu.dudau, steven.price, dri-devel, linux-kernel,
maarten.lankhorst, mripard, tzimmermann, airlied, daniel, nd
On Mon, 20 Oct 2025 21:02:43 +0100
Akash Goel <akash.goel@arm.com> 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)
>
> Fixes: 647810ec2476 ("drm/panthor: Add the MMU/VM logical block")
> Signed-off-by: Akash Goel <akash.goel@arm.com>
Just one minor thing below, but the patch is
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
regardless.
> ---
> drivers/gpu/drm/panthor/panthor_mmu.c | 16 +++++++++++++++-
> 1 file changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c b/drivers/gpu/drm/panthor/panthor_mmu.c
> index 6dec4354e378..63af8ee89b08 100644
> --- a/drivers/gpu/drm/panthor/panthor_mmu.c
> +++ b/drivers/gpu/drm/panthor/panthor_mmu.c
> @@ -1146,6 +1146,18 @@ 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;
> + }
> + }
Maybe add a WARN_ON_ONCE() here.
> +}
> +
> static struct panthor_vma *
> panthor_vm_op_ctx_get_vma(struct panthor_vm_op_ctx *op_ctx)
> {
> @@ -2081,8 +2093,10 @@ 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.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2025-10-20 20:02 [PATCH v2] drm/panthor: Fix potential memleak of vma structure Akash Goel
2025-10-20 21:59 ` Liviu Dudau
2025-10-21 7:41 ` Boris Brezillon
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