This is a note to let you know that I've just added the patch titled
drm/mediatek: Correctly free sg_table in gem prime vmap
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-mediatek-correctly-free-sg_table-in-gem-prime-vmap.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From dcc583c225e659d5da34b4ad83914fd6b51e3dbf Mon Sep 17 00:00:00 2001
From: Chen-Yu Tsai <wenst@xxxxxxxxxxxx>
Date: Wed, 4 Oct 2023 16:32:24 +0800
Subject: drm/mediatek: Correctly free sg_table in gem prime vmap
From: Chen-Yu Tsai <wenst@xxxxxxxxxxxx>
commit dcc583c225e659d5da34b4ad83914fd6b51e3dbf upstream.
The MediaTek DRM driver implements GEM PRIME vmap by fetching the
sg_table for the object, iterating through the pages, and then
vmapping them. In essence, unlike the GEM DMA helpers which vmap
when the object is first created or imported, the MediaTek version
does it on request.
Unfortunately, the code never correctly frees the sg_table contents.
This results in a kernel memory leak. On a Hayato device with a text
console on the internal display, this results in the system running
out of memory in a few days from all the console screen cursor updates.
Add sg_free_table() to correctly free the contents of the sg_table. This
was missing despite explicitly required by mtk_gem_prime_get_sg_table().
Also move the "out" shortcut label to after the kfree() call for the
sg_table. Having sg_free_table() together with kfree() makes more sense.
The shortcut is only used when the object already has a kernel address,
in which case the pointer is NULL and kfree() does nothing. Hence this
change causes no functional change.
Fixes: 3df64d7b0a4f ("drm/mediatek: Implement gem prime vmap/vunmap function")
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Chen-Yu Tsai <wenst@xxxxxxxxxxxx>
Reviewed-by: CK Hu <ck.hu@xxxxxxxxxxxx>
Link: https://patchwork.kernel.org/project/dri-devel/patch/20231004083226.1940055-1-wenst@xxxxxxxxxxxx/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/mediatek/mtk_drm_gem.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
--- a/drivers/gpu/drm/mediatek/mtk_drm_gem.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_gem.c
@@ -234,6 +234,7 @@ int mtk_drm_gem_prime_vmap(struct drm_ge
npages = obj->size >> PAGE_SHIFT;
mtk_gem->pages = kcalloc(npages, sizeof(*mtk_gem->pages), GFP_KERNEL);
if (!mtk_gem->pages) {
+ sg_free_table(sgt);
kfree(sgt);
return -ENOMEM;
}
@@ -243,12 +244,15 @@ int mtk_drm_gem_prime_vmap(struct drm_ge
mtk_gem->kvaddr = vmap(mtk_gem->pages, npages, VM_MAP,
pgprot_writecombine(PAGE_KERNEL));
if (!mtk_gem->kvaddr) {
+ sg_free_table(sgt);
kfree(sgt);
kfree(mtk_gem->pages);
return -ENOMEM;
}
-out:
+ sg_free_table(sgt);
kfree(sgt);
+
+out:
iosys_map_set_vaddr(map, mtk_gem->kvaddr);
return 0;
Patches currently in stable-queue which might be from wenst@xxxxxxxxxxxx are
queue-6.1/drm-mediatek-correctly-free-sg_table-in-gem-prime-vmap.patch
