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authorChenyuan Mi <cymi20@fudan.edu.cn>2021-09-07 20:26:33 +0800
committerKarol Herbst <kherbst@redhat.com>2021-11-04 12:29:07 +0100
commit6bb8c2d51811eb5e6504f49efe3b089d026009d2 (patch)
tree397549feef0b9b03ae95b91220d97f07090c4088 /drivers/gpu
parent93f43ed81abec8c805e1b77eb1d20dbc51a24dc4 (diff)
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drm/nouveau/svm: Fix refcount leak bug and missing check against null bug
The reference counting issue happens in one exception handling path of nouveau_svmm_bind(). When cli->svm.svmm is null, the function forgets to decrease the refcount of mm increased by get_task_mm(), causing a refcount leak. Fix this issue by using mmput() to decrease the refcount in the exception handling path. Also, the function forgets to do check against null when get mm by get_task_mm(). Fix this issue by adding null check after get mm by get_task_mm(). Signed-off-by: Chenyuan Mi <cymi20@fudan.edu.cn> Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn> Signed-off-by: Xin Tan <tanxin.ctf@gmail.com> Fixes: 822cab6150d3 ("drm/nouveau/svm: check for SVM initialized before migrating") Reviewed-by: Lyude Paul <lyude@redhat.com> Reviewed-by: Ben Skeggs <bskeggs@redhat.com> Reviewed-by: Karol Herbst <kherbst@redhat.com> Signed-off-by: Karol Herbst <kherbst@redhat.com> Link: https://patchwork.freedesktop.org/patch/msgid/20210907122633.16665-1-cymi20@fudan.edu.cn Link: https://gitlab.freedesktop.org/drm/nouveau/-/merge_requests/14
Diffstat (limited to 'drivers/gpu')
-rw-r--r--drivers/gpu/drm/nouveau/nouveau_svm.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/gpu/drm/nouveau/nouveau_svm.c b/drivers/gpu/drm/nouveau/nouveau_svm.c
index b0c3422cb01f..9985bfde015a 100644
--- a/drivers/gpu/drm/nouveau/nouveau_svm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_svm.c
@@ -162,10 +162,14 @@ nouveau_svmm_bind(struct drm_device *dev, void *data,
*/
mm = get_task_mm(current);
+ if (!mm) {
+ return -EINVAL;
+ }
mmap_read_lock(mm);
if (!cli->svm.svmm) {
mmap_read_unlock(mm);
+ mmput(mm);
return -EINVAL;
}