From: Jakub Kicinski <kuba@kernel.org>
To: Ian Ray <ian.ray@gehealthcare.com>
Cc: horms@kernel.org, Tony Nguyen <anthony.l.nguyen@intel.com>,
Przemek Kitszel <przemyslaw.kitszel@intel.com>,
Andrew Lunn <andrew+netdev@lunn.ch>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Paolo Abeni <pabeni@redhat.com>,
brian.ruley@gehealthcare.com, intel-wired-lan@lists.osuosl.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [Intel-wired-lan] [PATCH v2] igb: Fix watchdog_task race with shutdown
Date: Mon, 9 Jun 2025 16:10:39 -0700 [thread overview]
Message-ID: <20250609161039.00c73103@kernel.org> (raw)
In-Reply-To: <aEaAGqP-KtcYCMs-@50995b80b0f4>
On Mon, 9 Jun 2025 09:32:58 +0300 Ian Ray wrote:
> On Thu, Jun 05, 2025 at 06:43:39PM -0700, Jakub Kicinski wrote:
> > On Tue, 3 Jun 2025 11:09:49 +0300 Ian Ray wrote:
> > > set_bit(__IGB_DOWN, &adapter->state);
> > > + timer_delete_sync(&adapter->watchdog_timer);
> > > + timer_delete_sync(&adapter->phy_info_timer);
> > > +
> > > + cancel_work_sync(&adapter->watchdog_task);
> >
> > This doesn't look very race-proof as watchdog_task
> > can schedule the timer as its last operation?
>
> Thanks for the reply. __IGB_DOWN is the key to this design.
>
> If watchdog_task runs *before* __IGB_DOWN is set, then the
> timer is stopped (by this patch) as required.
>
> However, if watchdog_task runs *after* __IGB_DOWN is set,
> then the timer will not even be started (by watchdog_task).
Well, yes, but what if the two functions run *simultaneously*
There is no mutual exclusion between these two pieces of code AFAICT
WARNING: multiple messages have this Message-ID (diff)
From: Jakub Kicinski <kuba@kernel.org>
To: Ian Ray <ian.ray@gehealthcare.com>
Cc: horms@kernel.org, Tony Nguyen <anthony.l.nguyen@intel.com>,
Przemek Kitszel <przemyslaw.kitszel@intel.com>,
Andrew Lunn <andrew+netdev@lunn.ch>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Paolo Abeni <pabeni@redhat.com>,
brian.ruley@gehealthcare.com, intel-wired-lan@lists.osuosl.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] igb: Fix watchdog_task race with shutdown
Date: Mon, 9 Jun 2025 16:10:39 -0700 [thread overview]
Message-ID: <20250609161039.00c73103@kernel.org> (raw)
In-Reply-To: <aEaAGqP-KtcYCMs-@50995b80b0f4>
On Mon, 9 Jun 2025 09:32:58 +0300 Ian Ray wrote:
> On Thu, Jun 05, 2025 at 06:43:39PM -0700, Jakub Kicinski wrote:
> > On Tue, 3 Jun 2025 11:09:49 +0300 Ian Ray wrote:
> > > set_bit(__IGB_DOWN, &adapter->state);
> > > + timer_delete_sync(&adapter->watchdog_timer);
> > > + timer_delete_sync(&adapter->phy_info_timer);
> > > +
> > > + cancel_work_sync(&adapter->watchdog_task);
> >
> > This doesn't look very race-proof as watchdog_task
> > can schedule the timer as its last operation?
>
> Thanks for the reply. __IGB_DOWN is the key to this design.
>
> If watchdog_task runs *before* __IGB_DOWN is set, then the
> timer is stopped (by this patch) as required.
>
> However, if watchdog_task runs *after* __IGB_DOWN is set,
> then the timer will not even be started (by watchdog_task).
Well, yes, but what if the two functions run *simultaneously*
There is no mutual exclusion between these two pieces of code AFAICT
next prev parent reply other threads:[~2025-06-09 23:10 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-03 8:09 [Intel-wired-lan] [PATCH v2] igb: Fix watchdog_task race with shutdown Ian Ray
2025-06-03 8:09 ` Ian Ray
2025-06-06 1:43 ` [Intel-wired-lan] " Jakub Kicinski
2025-06-06 1:43 ` Jakub Kicinski
2025-06-09 6:32 ` [Intel-wired-lan] " Ian Ray
2025-06-09 6:32 ` Ian Ray
2025-06-09 23:10 ` Jakub Kicinski [this message]
2025-06-09 23:10 ` Jakub Kicinski
2025-06-10 12:44 ` [Intel-wired-lan] " Ian Ray
2025-06-10 12:44 ` Ian Ray
2025-06-16 21:47 ` [Intel-wired-lan] " Jacob Keller
2025-06-27 13:28 ` Ian Ray
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