Hi Daniel, On 10/03/2021 12:40, דניאל ניב wrote: > Hello all, > after looking on the linux kernel source code(version 5.11.15) of the saa7164 driver, it seems like I found a memory leak. > I couldn't find a specific person that maintains the saa7164 driver in the kernel maintainers file, so I hope you can help me or forward me > to the right person. > > The leak is located at /drivers/media/pci/saa7164/saa7164-encoder.c file, in the next function: > int saa7164_encoder_register(struct saa7164_port *port) > > The bug is actually allocation of memory in the kernel heap, without explicitly freeing it. > > The memory allocation is happening here > (https://github.com/torvalds/linux/blob/v5.8/drivers/media/pci/saa7164/saa7164-vbi.c#L720 > <https://github.com/torvalds/linux/blob/v5.8/drivers/media/pci/saa7164/saa7164-vbi.c#L720>): > /* Allocate and register the video device node */ > port->v4l_device = saa7164_vbi_alloc(port,dev->pci, &saa7164_vbi_template, "vbi"); > > and if we look deeper in the function saa7164_vbi_alloc(...), we can see it eventually uses kzalloc() in order to allocate the memory. > Looking again at saa7164_encoder_register(...) function, we can see the next code block > (https://github.com/torvalds/linux/blob/v5.8/drivers/media/pci/saa7164/saa7164-vbi.c#L734 > <https://github.com/torvalds/linux/blob/v5.8/drivers/media/pci/saa7164/saa7164-vbi.c#L734>): > if (result < 0) { > printk(KERN_INFO "%s: can't register vbi device\n", > dev->name); > /* TODO: We're going to leak here if we don't dealloc > The buffers above. The unreg function can't deal wit it. > */ > goto failed; > } > > ````````failed: > return result; > > > that actually exists from the function without freeing the memory it allocated earlier. > This flow seems to happen when we can't register a vbi device. > It seems like we can trigger this flow. > > I would like to add some code that will free the allocated memory and fix the bug, > but I want to ask first if there is a point in doing that? will it be merged into the driver code? Sure, we accept patches for fixes like that. Just post the patch to the linux-media mailinglist. Make sure that you do post ascii only emails to the mailinglist, HTML emails (like the one you sent) will be silently dropped. This should be helpful: https://www.kernel.org/doc/html/latest/process/submitting-patches.html Regards, Hans > > Thanks in advance, > Danie Niv. >
