> -----Original Message----- > From: Sebastian von Ohr <vonohr@xxxxxxxxxxx> > Sent: Wednesday, April 8, 2020 12:42 PM > To: Radhey Shyam Pandey <radheys@xxxxxxxxxx>; Vinod Koul > <vkoul@xxxxxxxxxx>; Appana Durga Kedareswara Rao > <appanad@xxxxxxxxxx>; Michal Simek <michals@xxxxxxxxxx> > Cc: dmaengine@xxxxxxxxxxxxxxx > Subject: RE: [PATCH] dmaengine: xilinx_dma: Add missing check for empty > list > > > -----Original Message----- > > From: Radhey Shyam Pandey [mailto:radheys@xxxxxxxxxx] > > Sent: Tuesday, April 7, 2020 6:04 PM > > To: Sebastian von Ohr <vonohr@xxxxxxxxxxx>; Vinod Koul > > <vkoul@xxxxxxxxxx>; Appana Durga Kedareswara Rao > > <appanad@xxxxxxxxxx>; Michal Simek <michals@xxxxxxxxxx> > > Cc: dmaengine@xxxxxxxxxxxxxxx > > Subject: RE: [PATCH] dmaengine: xilinx_dma: Add missing check for > empty > > list > > > > Thanks for reminding me. Somehow I missed it. You mentioned in one > > of earlier thread that this bug is introduced it using dma_sync_wait to > > wait for DMA completion. So to reproduce the issue in xilinx axidma > > test client I have to replace issue_pending with sync_wait API? > > Yes, dma_sync_wait triggered the bug for me almost every transfer. In the > xilinx axidmatest this is probably best achieved by adding dma_sync_wait > before the wait_for_completion_timeout. I encountered the bug with your > xilinx-v2019.2.01 tag. On this tag it actually crashes the kernel with an > invalid memory access (because the residue is written to desc). With the > current driver version it probably seems to work fine. You might have to > add some debug print to verify that the active_list can indeed be empty in > xilinx_dma_tx_status. I tried with xilinx-v2019.2.01 tag and added dma_sync_wait before wait_for _completion_timeout still the bug is not reproduced. I guess it's difficult to reproduce as it is dependent on actual timing on the events i.e tx_status checks for cookie status and it is not complete. Then soon interrupt handler is triggered for transfer complete and it updates the empty list and when it is again accessed in tx_status it results in data corruption. But just to ensure that I am using the same sequence is it possible to share the patch for axidmatest client?
