On Thu, Feb 4, 2016 at 11:11 PM, David Rientjes <rient...@google.com> wrote: > On Thu, 4 Feb 2016, Dmitry Vyukov wrote: > >> Size of kmalloc() in vc_do_resize() is controlled by user. >> Too large kmalloc() size triggers WARNING message on console. >> >> Use __GFP_NOWARN for this kmalloc() to not scare admins. >> > > Hmm, this is hitting the WARN_ON_ONCE(!(gfp_mask & __GFP_NOWARN)) for > order >= MAX_ORDER. > > vc_do_resize() has > > if (cols > VC_RESIZE_MAXCOL || lines > VC_RESIZE_MAXROW) > return -EINVAL; > > so the appropriate fix would seem to be to reject sizes that would exceed > the page allocator's ability to return contiguous memory (MAX_ORDER) > rather than ever trying the allocation in the first place.
Hi David, Please see Alan response to original report here: https://groups.google.com/d/msg/syzkaller/ufjvr5j0URo/lTlpYP0DBQAJ I can't say that I fully understand it.
