Thanks > That can/should be done when we actually deal with error handling properly > in this path. I have applied your patch. -->So when we will actually deal with error handling properly? On 2019/3/1 5:02, Jens Axboe wrote: > On 2/20/19 6:27 AM, zhengbin wrote: >> When I use syzkaller test kernel, there is a NULL pointer dereference >> in register_disk. The better solution is add return code to >> __device_add_disk. There is a patchset(http://lists.infradead.org/pipermail >> /linux-nvme/2016-August/005860.html) from Fam Zheng, int this patchset, the >> modify is as follows: >> int device_add_disk() { >> ...alloc A... >> retval = alloc B >> if (retval) >> goto fail; >> ... >> fail: >> return retval; --->did not free A >> } >> There are many callers, ie: >> loop_add-->add_disk-->device_add_disk-->__device_add_disk >> loop_remove-->del_gendisk >> ----->This will free all resources, inclue B(free fail) >> >> Maybe the better way is that if device_add_disk return fail, it should >> free all resources? This needs to modify all the callers(Otherwise the >> callers will double free), unfortunately, I am not very familiar with it. > > That can/should be done when we actually deal with error handling properly > in this path. I have applied your patch. >
