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From: James Hogan <jhogan@kernel.org>
To: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Cc: Vinicius Costa Gomes <vinicius.gomes@intel.com>,
	Paul Menzel <pmenzel@molgen.mpg.de>,
	Tony Nguyen <anthony.l.nguyen@intel.com>,
	Jesse Brandeburg <jesse.brandeburg@intel.com>,
	netdev@vger.kernel.org, intel-wired-lan@lists.osuosl.org,
	Sasha Neftin <sasha.neftin@intel.com>,
	Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Subject: Re: [WIP v2] igc: fix deadlock caused by taking RTNL in RPM resume path
Date: Thu, 11 Aug 2022 22:41:48 +0100	[thread overview]
Message-ID: <4759452.31r3eYUQgx@saruman> (raw)
In-Reply-To: <20220811202524.78323-1-vinicius.gomes@intel.com>

On Thursday, 11 August 2022 21:25:24 BST Vinicius Costa Gomes wrote:
> It was reported a RTNL deadlock in the igc driver that was causing
> problems during suspend/resume.
> 
> The solution is similar to commit ac8c58f5b535 ("igb: fix deadlock
> caused by taking RTNL in RPM resume path").
> 
> Reported-by: James Hogan <jhogan@kernel.org>
> Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
> ---
> Sorry for the noise earlier, my kernel config didn't have runtime PM
> enabled.

Thanks for looking into this.

This is identical to the patch I've been running for the last week. The 
deadlock is avoided, however I now occasionally see an assertion from 
netif_set_real_num_tx_queues due to the lock not being taken in some cases via 
the runtime_resume path, and a suspicious rcu_dereference_protected() warning 
(presumably due to the same issue of the lock not being taken). See here for 
details:
https://lore.kernel.org/netdev/4765029.31r3eYUQgx@saruman/

Cheers
James



  reply	other threads:[~2022-08-11 21:41 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <4752347.31r3eYUQgx@saruman>
     [not found] ` <3198206.44csPzL39Z@saruman>
     [not found]   ` <e8f33b45-380f-e73e-3879-0e1a478262e9@molgen.mpg.de>
2022-08-04 21:41     ` [Intel-wired-lan] I225-V (igc driver) hangs after resume in igc_resume/igc_tsn_reset James Hogan
2022-08-04 22:07       ` James Hogan
2022-08-05 11:25         ` James Hogan
2022-08-11 15:13           ` [PATCH] igc: fix deadlock caused by taking RTNL in RPM resume path Vinicius Costa Gomes
2022-08-11 18:58             ` [Intel-wired-lan] " kernel test robot
2022-08-11 19:59             ` kernel test robot
2022-08-11 20:25             ` [WIP v2] " Vinicius Costa Gomes
2022-08-11 21:41               ` James Hogan [this message]
2022-08-13  0:05                 ` Vinicius Costa Gomes
2022-08-13 17:18                   ` James Hogan
2022-08-29  8:16                     ` James Hogan
2022-10-02 10:56                       ` James Hogan
2023-08-14 11:04                         ` James Hogan
2023-08-29  1:58                           ` Vinicius Costa Gomes
2023-09-03 17:57                             ` James Hogan

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