From: Amelie Delaunay <amelie.delaunay@foss.st.com> stable inclusion from stable-v5.10.210 commit 9de69732dde4e443c1c7f89acbbed2c45a6a8e17 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I97NHW CVE: CVE-2023-52492 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... --------------------------- [ Upstream commit f5c24d94512f1b288262beda4d3dcb9629222fc7 ] __dma_async_device_channel_register() can fail. In case of failure, chan->local is freed (with free_percpu()), and chan->local is nullified. When dma_async_device_unregister() is called (because of managed API or intentionally by DMA controller driver), channels are unconditionally unregistered, leading to this NULL pointer: [ 1.318693] Unable to handle kernel NULL pointer dereference at virtual address 00000000000000d0 [...] [ 1.484499] Call trace: [ 1.486930] device_del+0x40/0x394 [ 1.490314] device_unregister+0x20/0x7c [ 1.494220] __dma_async_device_channel_unregister+0x68/0xc0 Look at dma_async_device_register() function error path, channel device unregistration is done only if chan->local is not NULL. Then add the same condition at the beginning of __dma_async_device_channel_unregister() function, to avoid NULL pointer issue whatever the API used to reach this function. Fixes: d2fb0a043838 ("dmaengine: break out channel registration") Signed-off-by: Amelie Delaunay <amelie.delaunay@foss.st.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Link: https://lore.kernel.org/r/20231213160452.2598073-1-amelie.delaunay@foss.st.c... Signed-off-by: Vinod Koul <vkoul@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com> --- drivers/dma/dmaengine.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index 4ec7bb58c195..9559ebd61f3b 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -1108,6 +1108,9 @@ EXPORT_SYMBOL_GPL(dma_async_device_channel_register); static void __dma_async_device_channel_unregister(struct dma_device *device, struct dma_chan *chan) { + if (chan->local == NULL) + return; + WARN_ONCE(!device->device_release && chan->client_count, "%s called while %d clients hold a reference\n", __func__, chan->client_count); -- 2.25.1