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From: Ian Ray <ian.ray@gehealthcare.com>
To: Jakub Kicinski <kuba@kernel.org>
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 09:32:58 +0300	[thread overview]
Message-ID: <aEaAGqP-KtcYCMs-@50995b80b0f4> (raw)
In-Reply-To: <20250605184339.7a4e0f96@kernel.org>

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).

Regards,
Ian

  reply	other threads:[~2025-06-09  6:33 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-06-03  8:09 [PATCH v2] igb: Fix watchdog_task race with shutdown Ian Ray
2025-06-06  1:43 ` Jakub Kicinski
2025-06-09  6:32   ` Ian Ray [this message]
2025-06-09 23:10     ` Jakub Kicinski
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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