This is a note to let you know that I've just added the patch titled
drm/ttm: fix locking in vmap/vunmap TTM GEM helpers
to the 5.15-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-ttm-fix-locking-in-vmap-vunmap-ttm-gem-helpers.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From dbd0da2453c694f2f74651834d90fb280b57f151 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20K=C3=B6nig?= <christian.koenig@xxxxxxx>
Date: Fri, 15 Jul 2022 09:57:22 +0200
Subject: drm/ttm: fix locking in vmap/vunmap TTM GEM helpers
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From: Christian König <christian.koenig@xxxxxxx>
commit dbd0da2453c694f2f74651834d90fb280b57f151 upstream.
I've stumbled over this while reviewing patches for DMA-buf and it looks
like we completely messed the locking up here.
In general most TTM function should only be called while holding the
appropriate BO resv lock. Without this we could break the internal
buffer object state here.
Only compile tested!
Signed-off-by: Christian König <christian.koenig@xxxxxxx>
Fixes: 43676605f890 ("drm/ttm: Add vmap/vunmap to TTM and TTM GEM helpers")
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Dmitry Osipenko <dmitry.osipenko@xxxxxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20220715111533.467012-1-christian.koenig@xxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/drm_gem_ttm_helper.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
--- a/drivers/gpu/drm/drm_gem_ttm_helper.c
+++ b/drivers/gpu/drm/drm_gem_ttm_helper.c
@@ -64,8 +64,13 @@ int drm_gem_ttm_vmap(struct drm_gem_obje
struct dma_buf_map *map)
{
struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(gem);
+ int ret;
- return ttm_bo_vmap(bo, map);
+ dma_resv_lock(gem->resv, NULL);
+ ret = ttm_bo_vmap(bo, map);
+ dma_resv_unlock(gem->resv);
+
+ return ret;
}
EXPORT_SYMBOL(drm_gem_ttm_vmap);
@@ -82,7 +87,9 @@ void drm_gem_ttm_vunmap(struct drm_gem_o
{
struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(gem);
+ dma_resv_lock(gem->resv, NULL);
ttm_bo_vunmap(bo, map);
+ dma_resv_unlock(gem->resv);
}
EXPORT_SYMBOL(drm_gem_ttm_vunmap);
Patches currently in stable-queue which might be from christian.koenig@xxxxxxx are
queue-5.15/drm-ttm-fix-locking-in-vmap-vunmap-ttm-gem-helpers.patch
