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    SubjectRe: [PATCH 5.4 160/344] dmaengine: imx-sdma: Fix memory leak
    On Mon, Feb 24, 2020 at 03:57:18PM +0100, Sascha Hauer wrote:
    >On Mon, Feb 24, 2020 at 01:24:04PM +0000, Andreas Tobler wrote:
    >> Hi all,
    >>
    >> On 21.02.20 08:39, Greg Kroah-Hartman wrote:
    >> > From: Sascha Hauer <s.hauer@pengutronix.de>
    >> >
    >> > [ Upstream commit 02939cd167095f16328a1bd5cab5a90b550606df ]
    >> >
    >> > The current descriptor is not on any list of the virtual DMA channel.
    >> > Once sdma_terminate_all() is called when a descriptor is currently
    >> > in flight then this one is forgotten to be freed. We have to call
    >> > vchan_terminate_vdesc() on this descriptor to re-add it to the lists.
    >> > Now that we also free the currently running descriptor we can (and
    >> > actually have to) remove the current descriptor from its list also
    >> > for the cyclic case.
    >> >
    >> > Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
    >> > Reviewed-by: Robin Gong <yibin.gong@nxp.com>
    >> > Tested-by: Robin Gong <yibin.gong@nxp.com>
    >> > Link: https://lore.kernel.org/r/20191216105328.15198-10-s.hauer@pengutronix.de
    >> > Signed-off-by: Vinod Koul <vkoul@kernel.org>
    >> > Signed-off-by: Sasha Levin <sashal@kernel.org>
    >> > ---
    >> > drivers/dma/imx-sdma.c | 19 +++++++++++--------
    >> > 1 file changed, 11 insertions(+), 8 deletions(-)
    >> >
    >> > diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c
    >> > index c27e206a764c3..66f1b2ac5cde4 100644
    >> > --- a/drivers/dma/imx-sdma.c
    >> > +++ b/drivers/dma/imx-sdma.c
    >> > @@ -760,12 +760,8 @@ static void sdma_start_desc(struct sdma_channel *sdmac)
    >> > return;
    >> > }
    >> > sdmac->desc = desc = to_sdma_desc(&vd->tx);
    >> > - /*
    >> > - * Do not delete the node in desc_issued list in cyclic mode, otherwise
    >> > - * the desc allocated will never be freed in vchan_dma_desc_free_list
    >> > - */
    >> > - if (!(sdmac->flags & IMX_DMA_SG_LOOP))
    >> > - list_del(&vd->node);
    >> > +
    >> > + list_del(&vd->node);
    >> >
    >> > sdma->channel_control[channel].base_bd_ptr = desc->bd_phys;
    >> > sdma->channel_control[channel].current_bd_ptr = desc->bd_phys;
    >> > @@ -1071,7 +1067,6 @@ static void sdma_channel_terminate_work(struct work_struct *work)
    >> >
    >> > spin_lock_irqsave(&sdmac->vc.lock, flags);
    >> > vchan_get_all_descriptors(&sdmac->vc, &head);
    >> > - sdmac->desc = NULL;
    >> > spin_unlock_irqrestore(&sdmac->vc.lock, flags);
    >> > vchan_dma_desc_free_list(&sdmac->vc, &head);
    >> > sdmac->context_loaded = false;
    >> > @@ -1080,11 +1075,19 @@ static void sdma_channel_terminate_work(struct work_struct *work)
    >> > static int sdma_disable_channel_async(struct dma_chan *chan)
    >> > {
    >> > struct sdma_channel *sdmac = to_sdma_chan(chan);
    >> > + unsigned long flags;
    >> > +
    >> > + spin_lock_irqsave(&sdmac->vc.lock, flags);
    >> >
    >> > sdma_disable_channel(chan);
    >> >
    >> > - if (sdmac->desc)
    >> > + if (sdmac->desc) {
    >> > + vchan_terminate_vdesc(&sdmac->desc->vd);
    >> > + sdmac->desc = NULL;
    >> > schedule_work(&sdmac->terminate_worker);
    >> > + }
    >> > +
    >> > + spin_unlock_irqrestore(&sdmac->vc.lock, flags);
    >> >
    >> > return 0;
    >> > }
    >> >
    >>
    >> This patch breaks our imx6 board with the attached trace. Reverting the
    >> patch makes it boot again.
    >> I tried also 5.6-rc3 and it booted too. A closer look into imx-sdma.c
    >> from 5.6-rc3 showed me some details which might have to be backported as
    >> well to make this patch work.
    >> I tried a1ff6a07f5a3951fcac84f064a76d1ad79c10e40 and was somehow
    >> successful. I still have one trace but the board boots now.
    >>
    >> Any insights from the experts?
    >
    >This series should be applied as a whole or not, only 7/9 is optional.
    >
    >It seems I have to avoid the trigger word "fix" in my commit messages or
    >make sure these patches won't apply without their dependencies :-/

    Or you could just tag the dependencies so that we could take all of them
    as well? We have a nice "Depends-on:" tag that makes it easy.

    As with everything in life, you want to communicate more effectively
    rather than not communicate at all.

    --
    Thanks,
    Sasha

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