On Fri, Mar 3, 2017 at 8:36 AM, Dmitry Vyukov <dvyu...@google.com> wrote: > On Thu, Mar 2, 2017 at 8:37 PM, Greg Kroah-Hartman > <gre...@linuxfoundation.org> wrote: >>> >> This is hurting us badly. >>> > >>> > Really? How? Are you hitting this a lot? Why now and never before? >>> > Are you really out of memory? >>> >>> >>> This crashes our test bots a lot. >>> Why now... I don't have exact answer. Probably a combination of fuzzer >>> figuring out some magic sequences of syscalls and increased memory >>> consumption due to something (again maybe due to fuzzer figuring out >>> how to eat more memory). >> >> If the fuzzer is suddenly eating more memory, you should be seeing lots >> of other problems right? This can't be the only thing that has issues >> with memory allocation failures? > > > I remember 2 or 3 that started happenning roughly at the same time: > https://groups.google.com/forum/#!msg/syzkaller/tIx42qCVklk/fh0qjUboBgAJ > https://groups.google.com/forum/#!msg/syzkaller/vp1neyeoA8A/Is8aPdrpBgAJ > Both were quickly fixed. > There is strong bias towards failing larger, multi-page allocations. > so it's not that we are failing _all_ allocations in kernel code.
Mailed the patch officially. Once I fixed it, fuzzer was able to uncover another race leading to crashes in tty_ldisc_ref_wait: https://groups.google.com/d/msg/syzkaller/ZTsV9qLIzGA/opsLjyoEEAAJ
