From mboxrd@z Thu Jan 1 00:00:00 1970 From: vinod.koul@intel.com (Vinod Koul) Date: Thu, 23 May 2013 15:39:32 +0530 Subject: [PATCH] dmatest: abort transfers immediately when asked for In-Reply-To: References: <20130516153553.GI11706@mudshark.cambridge.arm.com> <1369139597-24446-1-git-send-email-andriy.shevchenko@linux.intel.com> <20130521151143.GH10453@mudshark.cambridge.arm.com> Message-ID: <20130523100932.GA30200@intel.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, May 21, 2013 at 08:24:15PM +0300, Andy Shevchenko wrote: > On Tue, May 21, 2013 at 6:11 PM, Will Deacon wrote: > > Hi Andy, > > > > On Tue, May 21, 2013 at 01:33:17PM +0100, Andy Shevchenko wrote: > >> When thread is going to be stopped we have to unconditionally terminate all > >> ongoing transfers. Otherwise it would be possible that callback function will > >> be called on the next interrupt and will try to access to already freed > >> structures. > >> > >> The patch introduces specific error message for this, though it doesn't > >> increase the counter of the failed tests. > >> > >> Signed-off-by: Andy Shevchenko > >> Reported-by: Will Deacon > > > > Thanks for persevering with this! Although this patch definitely fixes the > > panic I was seeing, I now observe buffer verification failures in subsequent > > test runs after an aborted run: > > I think the description to the commit adfa543e "dmatest: don't use > set_freezable_with_signal()" may shed light on this. > > The background (if I got it correctly) is in race with done flag. So, > we got a callback call from the DMA engine, but we don't know which > transfer triggers it. > I might be wrong. This is just an assumption. > > Have you ever see such behaviour on pre v3.10-rc1 kernels? (I mean > with old dmatest module) Terminate shouldnt cause the issue with buffer verfication, can you try this on dw_dmac, do you see similar failures on verfication? -- ~Vinod