From: Dave Jiang dave.jiang@intel.com
commit e594443196d6e0ef3d3b30320c49b3a4d4f9a547 upstream.
Channel device_node deletion is managed by the device driver rather than the dmaengine core. The deletion was accidentally introduced when making channel unregister dynamic. It causes xilinx_dma module to crash on unload as reported by Radhey. Remove chan->device_node delete in dmaengine and also fix up idxd driver.
[ 42.142705] Internal error: Oops: 96000044 [#1] SMP [ 42.147566] Modules linked in: xilinx_dma(-) clk_xlnx_clock_wizard uio_pdrv_genirq [ 42.155139] CPU: 1 PID: 2075 Comm: rmmod Not tainted 5.10.1-00026-g3a2e6dd7a05-dirty #192 [ 42.163302] Hardware name: Enclustra XU5 SOM (DT) [ 42.167992] pstate: 40000005 (nZcv daif -PAN -UAO -TCO BTYPE=--) [ 42.173996] pc : xilinx_dma_chan_remove+0x74/0xa0 [xilinx_dma] [ 42.179815] lr : xilinx_dma_chan_remove+0x70/0xa0 [xilinx_dma] [ 42.185636] sp : ffffffc01112bca0 [ 42.188935] x29: ffffffc01112bca0 x28: ffffff80402ea640
xilinx_dma_chan_remove+0x74/0xa0: __list_del at ./include/linux/list.h:112 (inlined by) __list_del_entry at./include/linux/list.h:135 (inlined by) list_del at ./include/linux/list.h:146 (inlined by) xilinx_dma_chan_remove at drivers/dma/xilinx/xilinx_dma.c:2546
Fixes: e81274cd6b52 ("dmaengine: add support to dynamic register/unregister of channels") Reported-by: Radhey Shyam Pandey radheys@xilinx.com Signed-off-by: Dave Jiang dave.jiang@intel.com Tested-by: Radhey Shyam Pandey radhey.shyam.pandey@xilinx.com Link: https://lore.kernel.org/r/161099092469.2495902.5064826526660062342.stgit@dji... Signed-off-by: Vinod Koul vkoul@kernel.org Cc: stable@vger.kernel.org # 5.9+ Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/dma/dmaengine.c | 1 - drivers/dma/idxd/dma.c | 5 ++++- 2 files changed, 4 insertions(+), 2 deletions(-)
--- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -1110,7 +1110,6 @@ static void __dma_async_device_channel_u "%s called while %d clients hold a reference\n", __func__, chan->client_count); mutex_lock(&dma_list_mutex); - list_del(&chan->device_node); device->chancnt--; chan->dev->chan = NULL; mutex_unlock(&dma_list_mutex); --- a/drivers/dma/idxd/dma.c +++ b/drivers/dma/idxd/dma.c @@ -214,5 +214,8 @@ int idxd_register_dma_channel(struct idx
void idxd_unregister_dma_channel(struct idxd_wq *wq) { - dma_async_device_channel_unregister(&wq->idxd->dma_dev, &wq->dma_chan); + struct dma_chan *chan = &wq->dma_chan; + + dma_async_device_channel_unregister(&wq->idxd->dma_dev, chan); + list_del(&chan->device_node); }