4469e03fa9
[ 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>
112 lines
3 KiB
C
Executable file
112 lines
3 KiB
C
Executable file
/*
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* Copyright 2012 Red Hat Inc.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
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* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
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* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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* OTHER DEALINGS IN THE SOFTWARE.
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*
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* Authors: Ben Skeggs
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*/
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#include "nouveau_drv.h"
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#include "nouveau_dma.h"
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#include "nouveau_fence.h"
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#include <nvif/if0004.h>
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#include <nvif/push006c.h>
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struct nv04_fence_chan {
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struct nouveau_fence_chan base;
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};
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struct nv04_fence_priv {
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struct nouveau_fence_priv base;
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};
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static int
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nv04_fence_emit(struct nouveau_fence *fence)
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{
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struct nvif_push *push = unrcu_pointer(fence->channel)->chan.push;
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int ret = PUSH_WAIT(push, 2);
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if (ret == 0) {
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PUSH_NVSQ(push, NV_SW, 0x0150, fence->base.seqno);
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PUSH_KICK(push);
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}
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return ret;
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}
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static int
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nv04_fence_sync(struct nouveau_fence *fence,
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struct nouveau_channel *prev, struct nouveau_channel *chan)
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{
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return -ENODEV;
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}
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static u32
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nv04_fence_read(struct nouveau_channel *chan)
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{
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struct nv04_nvsw_get_ref_v0 args = {};
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WARN_ON(nvif_object_mthd(&chan->nvsw, NV04_NVSW_GET_REF,
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&args, sizeof(args)));
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return args.ref;
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}
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static void
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nv04_fence_context_del(struct nouveau_channel *chan)
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{
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struct nv04_fence_chan *fctx = chan->fence;
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nouveau_fence_context_del(&fctx->base);
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chan->fence = NULL;
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nouveau_fence_context_free(&fctx->base);
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}
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static int
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nv04_fence_context_new(struct nouveau_channel *chan)
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{
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struct nv04_fence_chan *fctx = kzalloc(sizeof(*fctx), GFP_KERNEL);
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if (fctx) {
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nouveau_fence_context_new(chan, &fctx->base);
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fctx->base.emit = nv04_fence_emit;
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fctx->base.sync = nv04_fence_sync;
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fctx->base.read = nv04_fence_read;
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chan->fence = fctx;
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return 0;
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}
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return -ENOMEM;
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}
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static void
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nv04_fence_destroy(struct nouveau_drm *drm)
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{
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struct nv04_fence_priv *priv = drm->fence;
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drm->fence = NULL;
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kfree(priv);
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}
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int
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nv04_fence_create(struct nouveau_drm *drm)
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{
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struct nv04_fence_priv *priv;
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priv = drm->fence = kzalloc(sizeof(*priv), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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priv->base.dtor = nv04_fence_destroy;
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priv->base.context_new = nv04_fence_context_new;
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priv->base.context_del = nv04_fence_context_del;
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return 0;
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}
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