On Tue, Dec 19, 2017 at 9:37 AM, Tobin C. Harding <m...@tobin.cc> wrote: >> > <penguin-ker...@i-love.sakura.ne.jp> wrote: >> >> On 2017/12/18 22:40, syzbot wrote: >> >>> Hello, >> >>> >> >>> syzkaller hit the following crash on >> >>> 6084b576dca2e898f5c101baef151f7bfdbb606d >> >>> git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/master >> >>> compiler: gcc (GCC) 7.1.1 20170620 >> >>> .config is attached >> >>> Raw console output is attached. >> >>> >> >>> Unfortunately, I don't have any reproducer for this bug yet. >> >>> >> >>> >> >> >> >> This BUG is reporting >> >> >> >> [ 26.089789] usercopy: kernel memory overwrite attempt detected to >> >> 0000000022a5b430 (kmalloc-1024) (1024 bytes) >> >> >> >> line. But isn't 0000000022a5b430 strange for kmalloc(1024, GFP_KERNEL)ed >> >> kernel address? >> > >> > The address is hashed (see the %p threads for 4.15). >> >> >> +Tobin, is there a way to disable hashing entirely? The only >> designation of syzbot is providing crash reports to kernel developers >> with as much info as possible. It's fine for it to leak whatever. > > We have new specifier %px to print addresses in hex if leaking info is > not a worry.
This is not a per-printf-site thing. It's per-machine thing.
