| Message ID | 871sokyybc.wl%kuninori.morimoto.gx@renesas.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
Hi Morimoto-san, Thank you for the patch. On Thursday 10 Aug 2017 02:09:21 Kuninori Morimoto wrote: > Anton Volkov noticed that engine->dev is NULL before > of_dma_controller_register() in probe. > Thus there might be a NULL pointer dereference in > rcar_dmac_chan_start_xfer while accessing chan->chan.device->dev which > is equal to (&dmac->engine)->dev. > To be more safety code, this patch initialize dmac->engine before it. > > Reported-by: Anton Volkov <avolkov@ispras.ru> > Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> > --- > > > Anton, Laurent > > I created this patch because noone posted it yesterday. > Anton, you can use this patch and replace Author to you if you want. > Thus, I used [RFC] on this patch I don't think you have, the subject line is still "Re: Possible null pointer dereference in rcar-dmac.ko" :-) > drivers/dma/sh/rcar-dmac.c | 51 ++++++++++++++++++++----------------------- > 1 file changed, 26 insertions(+), 25 deletions(-) > > diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c > index ffcadca..6d60628 100644 > --- a/drivers/dma/sh/rcar-dmac.c > +++ b/drivers/dma/sh/rcar-dmac.c > @@ -1818,8 +1818,32 @@ static int rcar_dmac_probe(struct platform_device > *pdev) goto error; > } > > - /* Initialize the channels. */ > - INIT_LIST_HEAD(&dmac->engine.channels); > + /* Initialize engine */ > + engine = &dmac->engine; > + > + dma_cap_set(DMA_MEMCPY, engine->cap_mask); > + dma_cap_set(DMA_SLAVE, engine->cap_mask); > + > + engine->dev = &pdev->dev; > + engine->copy_align = ilog2(RCAR_DMAC_MEMCPY_XFER_SIZE); > + > + engine->src_addr_widths = widths; > + engine->dst_addr_widths = widths; > + engine->directions = BIT(DMA_MEM_TO_DEV) | BIT(DMA_DEV_TO_MEM); > + engine->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST; > + > + engine->device_alloc_chan_resources = rcar_dmac_alloc_chan_resources; > + engine->device_free_chan_resources = rcar_dmac_free_chan_resources; > + engine->device_prep_dma_memcpy = rcar_dmac_prep_dma_memcpy; > + engine->device_prep_slave_sg = rcar_dmac_prep_slave_sg; > + engine->device_prep_dma_cyclic = rcar_dmac_prep_dma_cyclic; > + engine->device_config = rcar_dmac_device_config; > + engine->device_terminate_all = rcar_dmac_chan_terminate_all; > + engine->device_tx_status = rcar_dmac_tx_status; > + engine->device_issue_pending = rcar_dmac_issue_pending; > + engine->device_synchronize = rcar_dmac_device_synchronize; > + > + INIT_LIST_HEAD(&engine->channels); I don't think this fully fixes the problem, as the rcar_dmac_isr_error() IRQ handler is still registered before all this. Furthermore, at least some of the initialization at the end of rcar_dmac_chan_probe() has to be moved before the rcar_dmac_isr_channel() IRQ handler registration. Let's not commit a quick hack but fix the problem correctly, we should ensure that all the initialization needed by IRQ handlers is performed before they get registered. > for (i = 0; i < dmac->n_channels; ++i) { > ret = rcar_dmac_chan_probe(dmac, &dmac->channels[i], > @@ -1839,29 +1863,6 @@ static int rcar_dmac_probe(struct platform_device > *pdev) * > * Default transfer size of 32 bytes requires 32-byte alignment. > */ > - engine = &dmac->engine; > - dma_cap_set(DMA_MEMCPY, engine->cap_mask); > - dma_cap_set(DMA_SLAVE, engine->cap_mask); > - > - engine->dev = &pdev->dev; > - engine->copy_align = ilog2(RCAR_DMAC_MEMCPY_XFER_SIZE); > - > - engine->src_addr_widths = widths; > - engine->dst_addr_widths = widths; > - engine->directions = BIT(DMA_MEM_TO_DEV) | BIT(DMA_DEV_TO_MEM); > - engine->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST; > - > - engine->device_alloc_chan_resources = rcar_dmac_alloc_chan_resources; > - engine->device_free_chan_resources = rcar_dmac_free_chan_resources; > - engine->device_prep_dma_memcpy = rcar_dmac_prep_dma_memcpy; > - engine->device_prep_slave_sg = rcar_dmac_prep_slave_sg; > - engine->device_prep_dma_cyclic = rcar_dmac_prep_dma_cyclic; > - engine->device_config = rcar_dmac_device_config; > - engine->device_terminate_all = rcar_dmac_chan_terminate_all; > - engine->device_tx_status = rcar_dmac_tx_status; > - engine->device_issue_pending = rcar_dmac_issue_pending; > - engine->device_synchronize = rcar_dmac_device_synchronize; > - > ret = dma_async_device_register(engine); > if (ret < 0) > goto error;
Hi Laurent > I don't think this fully fixes the problem, as the rcar_dmac_isr_error() IRQ > handler is still registered before all this. Furthermore, at least some of the > initialization at the end of rcar_dmac_chan_probe() has to be moved before the > rcar_dmac_isr_channel() IRQ handler registration. > > Let's not commit a quick hack but fix the problem correctly, we should ensure > that all the initialization needed by IRQ handlers is performed before they > get registered. Yeah, indeed. We need v2 patch Best regards --- Kuninori Morimoto -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c index ffcadca..6d60628 100644 --- a/drivers/dma/sh/rcar-dmac.c +++ b/drivers/dma/sh/rcar-dmac.c @@ -1818,8 +1818,32 @@ static int rcar_dmac_probe(struct platform_device *pdev) goto error; } - /* Initialize the channels. */ - INIT_LIST_HEAD(&dmac->engine.channels); + /* Initialize engine */ + engine = &dmac->engine; + + dma_cap_set(DMA_MEMCPY, engine->cap_mask); + dma_cap_set(DMA_SLAVE, engine->cap_mask); + + engine->dev = &pdev->dev; + engine->copy_align = ilog2(RCAR_DMAC_MEMCPY_XFER_SIZE); + + engine->src_addr_widths = widths; + engine->dst_addr_widths = widths; + engine->directions = BIT(DMA_MEM_TO_DEV) | BIT(DMA_DEV_TO_MEM); + engine->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST; + + engine->device_alloc_chan_resources = rcar_dmac_alloc_chan_resources; + engine->device_free_chan_resources = rcar_dmac_free_chan_resources; + engine->device_prep_dma_memcpy = rcar_dmac_prep_dma_memcpy; + engine->device_prep_slave_sg = rcar_dmac_prep_slave_sg; + engine->device_prep_dma_cyclic = rcar_dmac_prep_dma_cyclic; + engine->device_config = rcar_dmac_device_config; + engine->device_terminate_all = rcar_dmac_chan_terminate_all; + engine->device_tx_status = rcar_dmac_tx_status; + engine->device_issue_pending = rcar_dmac_issue_pending; + engine->device_synchronize = rcar_dmac_device_synchronize; + + INIT_LIST_HEAD(&engine->channels); for (i = 0; i < dmac->n_channels; ++i) { ret = rcar_dmac_chan_probe(dmac, &dmac->channels[i], @@ -1839,29 +1863,6 @@ static int rcar_dmac_probe(struct platform_device *pdev) * * Default transfer size of 32 bytes requires 32-byte alignment. */ - engine = &dmac->engine; - dma_cap_set(DMA_MEMCPY, engine->cap_mask); - dma_cap_set(DMA_SLAVE, engine->cap_mask); - - engine->dev = &pdev->dev; - engine->copy_align = ilog2(RCAR_DMAC_MEMCPY_XFER_SIZE); - - engine->src_addr_widths = widths; - engine->dst_addr_widths = widths; - engine->directions = BIT(DMA_MEM_TO_DEV) | BIT(DMA_DEV_TO_MEM); - engine->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST; - - engine->device_alloc_chan_resources = rcar_dmac_alloc_chan_resources; - engine->device_free_chan_resources = rcar_dmac_free_chan_resources; - engine->device_prep_dma_memcpy = rcar_dmac_prep_dma_memcpy; - engine->device_prep_slave_sg = rcar_dmac_prep_slave_sg; - engine->device_prep_dma_cyclic = rcar_dmac_prep_dma_cyclic; - engine->device_config = rcar_dmac_device_config; - engine->device_terminate_all = rcar_dmac_chan_terminate_all; - engine->device_tx_status = rcar_dmac_tx_status; - engine->device_issue_pending = rcar_dmac_issue_pending; - engine->device_synchronize = rcar_dmac_device_synchronize; - ret = dma_async_device_register(engine); if (ret < 0) goto error;