From: Steven Price <steven.price@arm.com>
To: "Boris Brezillon" <boris.brezillon@collabora.com>,
"Liviu Dudau" <liviu.dudau@arm.com>,
"Adrián Larumbe" <adrian.larumbe@collabora.com>
Cc: dri-devel@lists.freedesktop.org, kernel@collabora.com,
Eric Smith <eric.smith@collabora.com>
Subject: Re: [PATCH v3 4/5] drm/panthor: Fix an off-by-one in the heap context retrieval logic
Date: Thu, 2 May 2024 16:52:24 +0100 [thread overview]
Message-ID: <d2b2f36f-a2d4-4515-bc2c-24f4c1b548d3@arm.com> (raw)
In-Reply-To: <20240502154025.1425278-5-boris.brezillon@collabora.com>
On 02/05/2024 16:40, Boris Brezillon wrote:
> The heap ID is used to index the heap context pool, and allocating
> in the [1:MAX_HEAPS_PER_POOL] leads to an off-by-one. This was
> originally to avoid returning a zero heap handle, but given the handle
> is formed with (vm_id << 16) | heap_id, with vm_id > 0, we already can't
> end up with a valid heap handle that's zero.
>
> v3:
> - Allocate in the [0:MAX_HEAPS_PER_POOL-1] range
>
> v2:
> - New patch
>
> Fixes: 9cca48fa4f89 ("drm/panthor: Add the heap logical block")
> Reported-by: Eric Smith <eric.smith@collabora.com>
> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
> Tested-by: Eric Smith <eric.smith@collabora.com>
Don't we also need to change the xa_init_flags() in
panthor_heap_pool_create()?
Steve
> ---
> drivers/gpu/drm/panthor/panthor_heap.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/panthor/panthor_heap.c b/drivers/gpu/drm/panthor/panthor_heap.c
> index 683bb94761bc..252332f5390f 100644
> --- a/drivers/gpu/drm/panthor/panthor_heap.c
> +++ b/drivers/gpu/drm/panthor/panthor_heap.c
> @@ -323,7 +323,8 @@ int panthor_heap_create(struct panthor_heap_pool *pool,
> if (!pool->vm) {
> ret = -EINVAL;
> } else {
> - ret = xa_alloc(&pool->xa, &id, heap, XA_LIMIT(1, MAX_HEAPS_PER_POOL), GFP_KERNEL);
> + ret = xa_alloc(&pool->xa, &id, heap,
> + XA_LIMIT(0, MAX_HEAPS_PER_POOL - 1), GFP_KERNEL);
> if (!ret) {
> void *gpu_ctx = panthor_get_heap_ctx(pool, id);
>
next prev parent reply other threads:[~2024-05-02 15:52 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-02 15:40 [PATCH v3 0/5] drm/panthor: Collection of tiler heap related fixes Boris Brezillon
2024-05-02 15:40 ` [PATCH v3 1/5] drm/panthor: Fix tiler OOM handling to allow incremental rendering Boris Brezillon
2024-05-02 15:40 ` [PATCH v3 2/5] drm/panthor: Make sure the tiler initial/max chunks are consistent Boris Brezillon
2024-05-02 15:40 ` [PATCH v3 3/5] drm/panthor: Relax the constraints on the tiler chunk size Boris Brezillon
2024-05-02 15:47 ` Steven Price
2024-05-02 16:53 ` Boris Brezillon
2024-05-02 15:40 ` [PATCH v3 4/5] drm/panthor: Fix an off-by-one in the heap context retrieval logic Boris Brezillon
2024-05-02 15:52 ` Steven Price [this message]
2024-05-02 16:52 ` Boris Brezillon
2024-05-02 15:40 ` [PATCH v3 5/5] drm/panthor: Document drm_panthor_tiler_heap_destroy::handle validity constraints Boris Brezillon
2024-05-02 15:52 ` Steven Price
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