On Mon, Jan 09, 2017 at 11:01:29AM +0100, Iago Abal wrote: > Hi, > > With the help of a static bug finder (EBA - > http://www.iagoabal.eu/eba/) I have found a potential double-lock in > drivers/dma/pl330.c. This happens due to a recursive spin_lock_irqsave > on `pch->lock'. > > If this is indeed a bug, I will be happy to help with a patch. > > The trace is as follows: > > 1. Function `pl330_free_chan_resources' takes the lock for the first > time in line 2236: > > // https://github.com/torvalds/linux/blob/v4.10-rc2/drivers/dma/pl330.c#L2236 > spin_lock_irqsave(&pch->lock, flags); > > 2. Call to function `pl330_release_channel' immediately after; > > 3. Call to function `dma_pl330_rqcb' in line 1753; > > 4. Assuming that pch->thread->req[i].desc->pchan == pch, then function > `dma_pl330_rqcb' takes the lock again in line 1505: > > // https://github.com/torvalds/linux/blob/v4.10-rc2/drivers/dma/pl330.c#L1505 > spin_lock_irqsave(&pch->lock, flags); Yeah at first looks, it seems to be true, but then folks should have seen this Adding folks working on pl330 -- ~Vinod -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
