On Thursday, 27 May 2021 12:04:59 AM AEST Colin King wrote:
> The call to make_device_exclusive_range can potentially fail leaving
> pointer page not initialized that leads to an uninitialized pointer
> read issue. Fix this by adding a check to see if the call failed and
> returning the error code.
>
> Addresses-Coverity: ("Uninitialized pointer read")
> Fixes: c620bba9828c ("nouveau/svm: implement atomic SVM access")
> Signed-off-by: Colin Ian King
> ---
> drivers/gpu/drm/nouveau/nouveau_svm.c | 6 --
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/nouveau/nouveau_svm.c
> b/drivers/gpu/drm/nouveau/nouveau_svm.c index 84726a89e665..b913b4907088
> 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_svm.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_svm.c
> @@ -609,8 +609,10 @@ static int nouveau_atomic_range_fault(struct
> nouveau_svmm *svmm,
>
> notifier_seq = mmu_interval_read_begin(>notifier);
> mmap_read_lock(mm);
> - make_device_exclusive_range(mm, start, start + PAGE_SIZE,
> - , drm->dev);
> + ret = make_device_exclusive_range(mm, start, start +
> PAGE_SIZE, + ,
> drm->dev); + if (ret < 0)
> + goto out;
Thanks for spotting, this is fixing get_user_pages() inside
make_device_exclusive_range() returning an error. However the check needs to
happen after dropping mmap_lock below:
> mmap_read_unlock(mm);
> if (!page) {
> ret = -EINVAL;
> --
> 2.31.1
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