Hi Marek, On 20/05/2020 12:13, Marek Szyprowski wrote:
Hi Tomi, On 20.05.2020 11:00, Tomi Valkeinen wrote:Commit 9495b7e92f716ab2bd6814fab5e97ab4a39adfdd ("driver core: platform: Initialize dma_parms for platform devices") v5.7-rc5 causes at least some v4l2 platform drivers to break when freeing resources. E.g. drivers/media/platform/ti-vpe/cal.c uses vb2_dma_contig_set_max_seg_size() and vb2_dma_contig_clear_max_seg_size() to manage the dma_params, and similar pattern is seen in other drivers too. After 9495b7e92f716ab2, vb2_dma_contig_set_max_seg_size() will not allocate anything, but vb2_dma_contig_clear_max_seg_size() will still kfree the dma_params. I'm not sure what's the proper fix here. A flag somewhere to indicate that vb2_dma_contig_set_max_seg_size() did allocate, and thus vb2_dma_contig_clear_max_seg_size() must free? Or drop the kzalloc and kfree totally, if dma_params is now supposed to always be there?Thanks for reporting this issue! Once the mentioned commit has been merged, the code should assume that the platform devices does have a struct dma_params allocated, so the proper fix is to alloc dma_params only if the bus is not a platform bus: if (!dev_is_platform(dev) && !dev->dma_parms) { dev->dma_parms = kzalloc(sizeof(*dev->dma_parms), GFP_KERNEL); same check for the free path.
There is also "amba: Initialize dma_parms for amba devices". And the commit message says PCI devices do this too.
Guessing this based on the device type doesn't sound like a good idea to me. Tomi -- Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
