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authorBoris Brezillon <boris.brezillon@collabora.com>2019-11-29 14:59:02 +0100
committerRob Herring <robh@kernel.org>2019-12-06 11:05:52 -0600
commit70cc77952efebf6722d483cb83cfb563ac9768db (patch)
tree168d647aafe7a6c41b948ce3829ad68061a64148 /drivers/gpu/drm/panfrost/panfrost_drv.c
parentdrm/panfrost: devfreq: Round frequencies to OPPs (diff)
downloadlinux-dev-70cc77952efebf6722d483cb83cfb563ac9768db.tar.xz
linux-dev-70cc77952efebf6722d483cb83cfb563ac9768db.zip
drm/panfrost: Fix a race in panfrost_ioctl_madvise()
If 2 threads change the MADVISE property of the same BO in parallel we might end up with an shmem->madv value that's inconsistent with the presence of the BO in the shrinker list. The easiest solution to fix that is to protect the drm_gem_shmem_madvise() call with the shrinker lock. Fixes: 013b65101315 ("drm/panfrost: Add madvise and shrinker support") Cc: <stable@vger.kernel.org> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com> Reviewed-by: Steven Price <steven.price@arm.com> Acked-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com> Signed-off-by: Rob Herring <robh@kernel.org> Link: https://patchwork.freedesktop.org/patch/msgid/20191129135908.2439529-3-boris.brezillon@collabora.com
Diffstat (limited to 'drivers/gpu/drm/panfrost/panfrost_drv.c')
-rw-r--r--drivers/gpu/drm/panfrost/panfrost_drv.c9
1 files changed, 4 insertions, 5 deletions
diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c
index 9d086133a84e..8b8d6546cfac 100644
--- a/drivers/gpu/drm/panfrost/panfrost_drv.c
+++ b/drivers/gpu/drm/panfrost/panfrost_drv.c
@@ -347,20 +347,19 @@ static int panfrost_ioctl_madvise(struct drm_device *dev, void *data,
return -ENOENT;
}
+ mutex_lock(&pfdev->shrinker_lock);
args->retained = drm_gem_shmem_madvise(gem_obj, args->madv);
if (args->retained) {
struct panfrost_gem_object *bo = to_panfrost_bo(gem_obj);
- mutex_lock(&pfdev->shrinker_lock);
-
if (args->madv == PANFROST_MADV_DONTNEED)
- list_add_tail(&bo->base.madv_list, &pfdev->shrinker_list);
+ list_add_tail(&bo->base.madv_list,
+ &pfdev->shrinker_list);
else if (args->madv == PANFROST_MADV_WILLNEED)
list_del_init(&bo->base.madv_list);
-
- mutex_unlock(&pfdev->shrinker_lock);
}
+ mutex_unlock(&pfdev->shrinker_lock);
drm_gem_object_put_unlocked(gem_obj);
return 0;