diff options
| author | Amelie Delaunay <amelie.delaunay@foss.st.com> | 2023-12-13 17:04:52 +0100 |
|---|---|---|
| committer | Vinod Koul <vkoul@kernel.org> | 2023-12-21 21:44:29 +0530 |
| commit | f5c24d94512f1b288262beda4d3dcb9629222fc7 (patch) | |
| tree | d00a6fee7e977d9a59c5ad48c479c37e85c49c2b /drivers/dma/dmaengine.c | |
| parent | d0e217b72f9f5c5ef35e3423d393ea8093ce98ec (diff) | |
dmaengine: fix NULL pointer in channel unregistration function
__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.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Diffstat (limited to 'drivers/dma/dmaengine.c')
| -rw-r--r-- | drivers/dma/dmaengine.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index b7388ae62d7f..491b22240221 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -1103,6 +1103,9 @@ 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); |