On Thu, Apr 10, 2025 at 03:33:40PM +0200, Alexander Lobakin wrote: > From: Leon Romanovsky <l...@kernel.org> > Date: Thu, 10 Apr 2025 16:27:06 +0300 > > > On Thu, Apr 10, 2025 at 02:58:28PM +0200, Larysa Zaremba wrote: > >> On Thu, Apr 10, 2025 at 02:23:49PM +0300, Leon Romanovsky wrote: > >>> On Thu, Apr 10, 2025 at 12:44:33PM +0200, Larysa Zaremba wrote: > >>>> On Thu, Apr 10, 2025 at 11:21:37AM +0300, Leon Romanovsky wrote: > >>>>> On Tue, Apr 08, 2025 at 02:47:51PM +0200, Larysa Zaremba wrote: > >>>>>> From: Phani R Burra <phani.r.bu...@intel.com> > >>>>>> > >>>>>> Libeth will now support control queue setup and configuration APIs. > >>>>>> These are mainly used for mailbox communication between drivers and > >>>>>> control plane. > >>>>>> > >>>>>> Make use of the page pool support for managing controlq buffers. > >>>>> > >>>>> <...> > >>>>> > >>>>>> libeth-y := rx.o > >>>>>> > >>>>>> +obj-$(CONFIG_LIBETH_CP) += libeth_cp.o > >>>>>> + > >>>>>> +libeth_cp-y := controlq.o > >>>>> > >>>>> So why did you create separate module for it? > >>>>> Now you have pci -> libeth -> libeth_cp -> ixd, with the potential > >>>>> races between ixd and libeth, am I right? > >>>>> > >>>> > >>>> I am not sure what kind of races do you mean, all libeth modules > >>>> themselves are > >>>> stateless and will stay this way [0], all used data is owned by drivers. > >>> > >>> Somehow such separation doesn't truly work. There are multiple syzkaller > >>> reports per-cycle where module A tries to access module C, which already > >>> doesn't exist because it was proxied through module B. > >> > >> Are there similar reports for libeth and libie modules when iavf is > >> enabled? > > > > To get such report, syzkaller should run on physical iavf, it looks like it > > doesn't. > > Did I miss it here? > > https://syzkaller.appspot.com/upstream/s/net > > > >> It is basically the same hierarchy. (iavf uses both libeth and libie, > >> libie > >> depends on libeth). > >> > >> I am just trying to understand, is this a regular situation or did I just > >> mess > >> smth up? > > > > My review comment was general one. It is almost impossible to review > > this newly proposed architecture split for correctness. > > > >> > >>> > >>>> > >>>> As for the module separation, I think there is no harm in keeping it > >>>> modular. > >>> > >>> Syzkaller reports disagree with you. > >>> > >> > >> Could you please share them? > > > > It is not an easy question to answer, because all these reports are > > complaining > > about some wrong locking order or NULL-pointer access. You will never know > > if > > it is because of programming or design error. > > > > As an approximate example, see commits a27c6f46dcec ("RDMA/bnxt_re: Fix an > > issue in bnxt_re_async_notifier") > > and f0df225d12fc ("RDMA/bnxt_re: Add sanity checks on rdev validity"). > > At the first glance, they look unrelated to our discussion, however > > they can serve as an example or races between deinit/disable paths in > > parent module vs. child. > > Unrelated. At first, you were talking about module dependencies, now > you're talking about struct device etc dependencies, which is a > completely different thing. > > As already said, libeth is stateless, so the latter one can't happen. > The former one is impossible at all. As long as at least 1 child module > is loaded, you can't unload the parent. And load/unload is serialized, > see module core code.
It is not only module load/unload. It is bind/unbind, devlink operations e.t.c, everything that can cause to reload driver in module C. Thanks
