ping
On 2019/2/20 21:27, 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.
>
> zhengbin (1):
> Fix NULL pointer dereference in register_disk
>
> block/genhd.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> --
> 2.7.4
>
>
> .
>
