On Sat, Jan 2, 2016 at 12:33 PM, Manfred Spraul <manf...@colorfullife.com> wrote: > Hi Dmitry, > > shm locking differs too much from msg/sem locking, I never looked at it in > depth, so I'm not able to perform a proper review. > > Except for the obvious: Races that can be triggered from user space are > inacceptable. > Regardless if there is a BUG_ON, a WARN_ON or nothing at all. > > On 12/21/2015 04:44 PM, Dmitry Vyukov wrote: >>> >>> + >>> +/* This is called by fork, once for every shm attach. */ >>> +static void shm_open(struct vm_area_struct *vma) >>> +{ >>> + int err = __shm_open(vma); >>> + /* >>> + * We raced in the idr lookup or with shm_destroy(). >>> + * Either way, the ID is busted. >>> + */ >>> + WARN_ON_ONCE(err); >>> } > > Is it possible to trigger this race? Parallel IPC_RMID & fork()?
Hi Manfred, As far as I see my reproducer triggers exactly this warning (and later a crash). -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/