Messages in this thread | | | Date | Fri, 1 Apr 2022 10:47:30 +0200 | From | Ivan Vecera <> | Subject | Re: [Intel-wired-lan] [PATCH net] ice: Fix incorrect locking in ice_vc_process_vf_msg() |
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On Thu, 31 Mar 2022 19:59:11 +0000 "Keller, Jacob E" <jacob.e.keller@intel.com> wrote:
> > -----Original Message----- > > From: Brett Creeley <brett@pensando.io> > > Sent: Thursday, March 31, 2022 9:33 AM > > To: Fijalkowski, Maciej <maciej.fijalkowski@intel.com> > > Cc: ivecera <ivecera@redhat.com>; netdev@vger.kernel.org; moderated > > list:INTEL ETHERNET DRIVERS <intel-wired-lan@lists.osuosl.org>; mschmidt > > <mschmidt@redhat.com>; open list <linux-kernel@vger.kernel.org>; poros > > <poros@redhat.com>; Jakub Kicinski <kuba@kernel.org>; Paolo Abeni > > <pabeni@redhat.com>; David S. Miller <davem@davemloft.net>; Keller, Jacob E > > <jacob.e.keller@intel.com> > > Subject: Re: [Intel-wired-lan] [PATCH net] ice: Fix incorrect locking in > > ice_vc_process_vf_msg() > > > > On Thu, Mar 31, 2022 at 6:17 AM Maciej Fijalkowski > > <maciej.fijalkowski@intel.com> wrote: > > > > > > On Thu, Mar 31, 2022 at 03:14:32PM +0200, Maciej Fijalkowski wrote: > > > > On Thu, Mar 31, 2022 at 12:50:04PM +0200, Ivan Vecera wrote: > > > > > Usage of mutex_trylock() in ice_vc_process_vf_msg() is incorrect > > > > > because message sent from VF is ignored and never processed. > > > > > > > > > > Use mutex_lock() instead to fix the issue. It is safe because this > > > > > > > > We need to know what is *the* issue in the first place. > > > > Could you please provide more context what is being fixed to the readers > > > > that don't have an access to bugzilla? > > > > > > > > Specifically, what is the case that ignoring a particular message when > > > > mutex is already held is a broken behavior? > > > > > > Uh oh, let's > > > CC: Brett Creeley <brett@pensando.io> > > > > Thanks for responding, Brett! :) > > > My concern here is that we don't want to handle messages > > from the context of the "previous" VF configuration if that > > makes sense. > > > > Makes sense. Perhaps we need to do some sort of "clear the existing message queue" when we initiate a reset?
I think this logic is already there... Function ice_reset_vf() (running under cfg_lock) sets default allowlist during reset (these are VIRTCHNL_OP_GET_VF_RESOURCES, VIRTCHNL_OP_VERSION, VIRTCHNL_OP_RESET_VF). Function ice_vc_process_vf_msg() currently processed message whether is allowed or not so any spurious messages there were sent by VF prior reset should be dropped already.
> > > It might be best to grab the cfg_lock before doing any > > message/VF validating in ice_vc_process_vf_msg() to > > make sure all of the checks are done under the cfg_lock. > > > > Yes that seems like it should be done.
Yes, the mutex should be placed prior ice_vc_is_opcode_allowed() call to serialize accesses to allowlist. Will send v2.
Thanks, Ivan
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