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| author | Abhinav Singh <singhabhinav9051571833@gmail.com> | 2023-11-13 22:13:03 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-01-26 02:35:31 +0300 |
| commit | 9f91aa1ef9180f18cf14f56e4610243da614a9c2 (patch) | |
| tree | 62bf93ae3bbf8fdfdebb4948cbde77e23ab182ac /drivers/gpu/drm/nouveau | |
| parent | a23571137dd10e22dcf398d60b00db7df5478ab6 (diff) | |
| download | linux-9f91aa1ef9180f18cf14f56e4610243da614a9c2.tar.xz | |
drm/nouveau/fence:: fix warning directly dereferencing a rcu pointer
[ Upstream commit 5f35a624c1e30b5bae5023b3c256e94e0ad4f806 ]
Fix a sparse warning with this message
"warning:dereference of noderef expression". In this context it means we
are dereferencing a __rcu tagged pointer directly.
We should not be directly dereferencing a rcu pointer. To get a normal
(non __rcu tagged pointer) from a __rcu tagged pointer we are using the
function unrcu_pointer(...). The non __rcu tagged pointer then can be
dereferenced just like a normal pointer.
I tested with qemu with this command
qemu-system-x86_64 \
-m 2G \
-smp 2 \
-kernel bzImage \
-append "console=ttyS0 root=/dev/sda earlyprintk=serial net.ifnames=0" \
-drive file=bullseye.img,format=raw \
-net user,host=10.0.2.10,hostfwd=tcp:127.0.0.1:10021-:22 \
-net nic,model=e1000 \
-enable-kvm \
-nographic \
-pidfile vm.pid \
2>&1 | tee vm.log
with lockdep enabled.
Fixes: 0ec5f02f0e2c ("drm/nouveau: prevent stale fence->channel pointers, and protect with rcu")
Signed-off-by: Abhinav Singh <singhabhinav9051571833@gmail.com>
Signed-off-by: Danilo Krummrich <dakr@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231113191303.3277733-1-singhabhinav9051571833@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/gpu/drm/nouveau')
| -rw-r--r-- | drivers/gpu/drm/nouveau/nv04_fence.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/gpu/drm/nouveau/nv04_fence.c b/drivers/gpu/drm/nouveau/nv04_fence.c index 5b71a5a5cd85..cdbc75e3d1f6 100644 --- a/drivers/gpu/drm/nouveau/nv04_fence.c +++ b/drivers/gpu/drm/nouveau/nv04_fence.c @@ -39,7 +39,7 @@ struct nv04_fence_priv { static int nv04_fence_emit(struct nouveau_fence *fence) { - struct nvif_push *push = fence->channel->chan.push; + struct nvif_push *push = unrcu_pointer(fence->channel)->chan.push; int ret = PUSH_WAIT(push, 2); if (ret == 0) { PUSH_NVSQ(push, NV_SW, 0x0150, fence->base.seqno); |