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Sat, 13 Aug 2022 00:05:53 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6400,9594,10437"; a="289280228" X-IronPort-AV: E=Sophos;i="5.93,233,1654585200"; d="scan'208";a="289280228" Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Aug 2022 17:05:52 -0700 X-IronPort-AV: E=Sophos;i="5.93,233,1654585200"; d="scan'208";a="933897974" Received: from vedsingh-mobl1.amr.corp.intel.com (HELO vcostago-mobl3) ([10.209.2.208]) by fmsmga005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Aug 2022 17:05:52 -0700 From: Vinicius Costa Gomes To: James Hogan In-Reply-To: <4759452.31r3eYUQgx@saruman> References: <20220811151342.19059-1-vinicius.gomes@intel.com> <20220811202524.78323-1-vinicius.gomes@intel.com> <4759452.31r3eYUQgx@saruman> Date: Fri, 12 Aug 2022 21:05:41 -0300 Message-ID: <87o7wpxb1m.fsf@intel.com> MIME-Version: 1.0 X-Mailman-Original-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1660349154; x=1691885154; h=from:to:cc:subject:in-reply-to:references:date: message-id:mime-version; bh=/unn/GWSSxZQI3S+V3HdZHplY4oCOpStK/WAzsbYOiU=; b=atm2TGLlNvcdZTAdN2SOqKYmtLRXPB3S9BP7v/tbaQ3FyV+W3oO4g+1D IjVUSd3lV2nCUb7cEzBMVsSMlzVpGXC/FSgQ8bEw3ouuYKa4Ru6L87+l1 hz3Pg5ICt3i7m4P2b9d916/PW5DKart26t7HyNc0AmyKRLjwpj9rw077B TxGM81MmwLi8D0U1Kl18G0fVi+aJjxYuSGlmawCz87lfkLO0qfAEs5xJf wnH0MJJHztEVu9hjIoGu2/OB6LqQnzBPTnOKv10LptaZbNkzY742ObdjY MzpEaDZv60MS193UtFOkFtGlo+xy1LX/i+zXcgOSHtwSlcYFC040fM6iQ A==; X-Mailman-Original-Authentication-Results: smtp1.osuosl.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.a=rsa-sha256 header.s=Intel header.b=atm2TGLl Subject: Re: [Intel-wired-lan] [WIP v2] igc: fix deadlock caused by taking RTNL in RPM resume path X-BeenThere: intel-wired-lan@osuosl.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel Wired Ethernet Linux Kernel Driver Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Paul Menzel , netdev@vger.kernel.org, Jesse Brandeburg , Aleksandr Loktionov , intel-wired-lan@lists.osuosl.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: intel-wired-lan-bounces@osuosl.org Sender: "Intel-wired-lan" Hi James, James Hogan writes: > 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 >> Signed-off-by: Vinicius Costa Gomes >> --- >> 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/ Oh, sorry. I missed the part that the rtnl assert splat was already using similar/identical code to what I got/copied from igb. So what this seems to be telling us is that the "fix" from igb is only hiding the issue, and we would need to remove the need for taking the RTNL for the suspend/resume paths in igc and igb? (as someone else said in that igb thread, iirc) Cheers, -- Vinicius _______________________________________________ Intel-wired-lan mailing list Intel-wired-lan@osuosl.org https://lists.osuosl.org/mailman/listinfo/intel-wired-lan