From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 34082C31E49 for ; Sun, 16 Jun 2019 07:09:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F355A21707 for ; Sun, 16 Jun 2019 07:09:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560668959; bh=hvH/uITKMS5seQn+VJ3oEo3HYiTI5KLJ/SX8eTOVYyo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=xBkadDc72ubko6Gaj9Y9+W/NsE0oKs3DxZffyk8Ie6BRwyvuGoYuDDb/mGReDLkKM mXgyptGBqFGpMc7gXxfnWlGYl4r1pyzayzP9wvJVcFRA77inJSjwsP4P5WjDKiRisv 9MmcF+zaTXRpSn5XpCt5B+nFiTrwbyLUE74jA65o= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725888AbfFPHJS (ORCPT ); Sun, 16 Jun 2019 03:09:18 -0400 Received: from mail.kernel.org ([198.145.29.99]:49128 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725860AbfFPHJS (ORCPT ); Sun, 16 Jun 2019 03:09:18 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3BF78216C8; Sun, 16 Jun 2019 07:09:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560668956; bh=hvH/uITKMS5seQn+VJ3oEo3HYiTI5KLJ/SX8eTOVYyo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Ipmr3tI0PLaYfwWUDHL91VpLwaa9+0vpu73DXn3eZ+eO/wXJlGNGScFB0e0bODjwd 8XHgJkstTbXRiNiYyeq95vYt7gedaDqn/cLWggHS0u0DJswJA91a2Vd5a7j9q/vrGA P2qiK2vTdgne4vaXsnn1IsCwE9i6STWNrIrIDbJA= Date: Sun, 16 Jun 2019 09:09:14 +0200 From: Greg Kroah-Hartman To: Sasha Levin Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Scott Wood , Wu Hao , Alan Tull , linux-fpga@vger.kernel.org Subject: Re: [PATCH AUTOSEL 5.1 16/59] fpga: dfl: Add lockdep classes for pdata->lock Message-ID: <20190616070914.GA4464@kroah.com> References: <20190614202843.26941-1-sashal@kernel.org> <20190614202843.26941-16-sashal@kernel.org> <20190615054739.GA23883@kroah.com> <20190615224159.GU1513@sasha-vm> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190615224159.GU1513@sasha-vm> User-Agent: Mutt/1.12.0 (2019-05-25) Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Sat, Jun 15, 2019 at 06:41:59PM -0400, Sasha Levin wrote: > On Sat, Jun 15, 2019 at 07:47:39AM +0200, Greg Kroah-Hartman wrote: > > On Fri, Jun 14, 2019 at 04:28:00PM -0400, Sasha Levin wrote: > > > From: Scott Wood > > > > > > [ Upstream commit dfe3de8d397bf878b31864d4e489d41118ec475f ] > > > > > > struct dfl_feature_platform_data (and it's mutex) is used > > > by both fme and port devices, and when lockdep is enabled it > > > complains about nesting between these locks. Tell lockdep about > > > the difference so it can track each class separately. > > > > > > Here's the lockdep complaint: > > > [ 409.680668] WARNING: possible recursive locking detected > > > [ 409.685983] 5.1.0-rc3.fpga+ #1 Tainted: G E > > > [ 409.691469] -------------------------------------------- > > > [ 409.696779] fpgaconf/9348 is trying to acquire lock: > > > [ 409.701746] 00000000a443fe2e (&pdata->lock){+.+.}, at: port_enable_set+0x24/0x60 [dfl_afu] > > > [ 409.710006] > > > [ 409.710006] but task is already holding lock: > > > [ 409.715837] 0000000063b78782 (&pdata->lock){+.+.}, at: fme_pr_ioctl+0x21d/0x330 [dfl_fme] > > > [ 409.724012] > > > [ 409.724012] other info that might help us debug this: > > > [ 409.730535] Possible unsafe locking scenario: > > > [ 409.730535] > > > [ 409.736457] CPU0 > > > [ 409.738910] ---- > > > [ 409.741360] lock(&pdata->lock); > > > [ 409.744679] lock(&pdata->lock); > > > [ 409.747999] > > > [ 409.747999] *** DEADLOCK *** > > > [ 409.747999] > > > [ 409.753920] May be due to missing lock nesting notation > > > [ 409.753920] > > > [ 409.760704] 4 locks held by fpgaconf/9348: > > > [ 409.764805] #0: 0000000063b78782 (&pdata->lock){+.+.}, at: fme_pr_ioctl+0x21d/0x330 [dfl_fme] > > > [ 409.773408] #1: 00000000213c8a66 (®ion->mutex){+.+.}, at: fpga_region_program_fpga+0x24/0x200 [fpga_region] > > > [ 409.783489] #2: 00000000fe63afb9 (&mgr->ref_mutex){+.+.}, at: fpga_mgr_lock+0x15/0x40 [fpga_mgr] > > > [ 409.792354] #3: 000000000b2285c5 (&bridge->mutex){+.+.}, at: __fpga_bridge_get+0x26/0xa0 [fpga_bridge] > > > [ 409.801740] > > > [ 409.801740] stack backtrace: > > > [ 409.806102] CPU: 45 PID: 9348 Comm: fpgaconf Kdump: loaded Tainted: G E 5.1.0-rc3.fpga+ #1 > > > [ 409.815658] Hardware name: Intel Corporation S2600BT/S2600BT, BIOS SE5C620.86B.01.00.0763.022420181017 02/24/2018 > > > [ 409.825911] Call Trace: > > > [ 409.828369] dump_stack+0x5e/0x8b > > > [ 409.831686] __lock_acquire+0xf3d/0x10e0 > > > [ 409.835612] ? find_held_lock+0x3c/0xa0 > > > [ 409.839451] lock_acquire+0xbc/0x1d0 > > > [ 409.843030] ? port_enable_set+0x24/0x60 [dfl_afu] > > > [ 409.847823] ? port_enable_set+0x24/0x60 [dfl_afu] > > > [ 409.852616] __mutex_lock+0x86/0x970 > > > [ 409.856195] ? port_enable_set+0x24/0x60 [dfl_afu] > > > [ 409.860989] ? port_enable_set+0x24/0x60 [dfl_afu] > > > [ 409.865777] ? __mutex_unlock_slowpath+0x4b/0x290 > > > [ 409.870486] port_enable_set+0x24/0x60 [dfl_afu] > > > [ 409.875106] fpga_bridges_disable+0x36/0x50 [fpga_bridge] > > > [ 409.880502] fpga_region_program_fpga+0xea/0x200 [fpga_region] > > > [ 409.886338] fme_pr_ioctl+0x13e/0x330 [dfl_fme] > > > [ 409.890870] fme_ioctl+0x66/0xe0 [dfl_fme] > > > [ 409.894973] do_vfs_ioctl+0xa9/0x720 > > > [ 409.898548] ? lockdep_hardirqs_on+0xf0/0x1a0 > > > [ 409.902907] ksys_ioctl+0x60/0x90 > > > [ 409.906225] __x64_sys_ioctl+0x16/0x20 > > > [ 409.909981] do_syscall_64+0x5a/0x220 > > > [ 409.913644] entry_SYSCALL_64_after_hwframe+0x49/0xbe > > > [ 409.918698] RIP: 0033:0x7f9d31b9b8d7 > > > [ 409.922276] Code: 44 00 00 48 8b 05 b9 15 2d 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 89 15 2d 00 f7 d8 64 89 01 48 > > > [ 409.941020] RSP: 002b:00007ffe4cae0d68 EFLAGS: 00000202 ORIG_RAX: 0000000000000010 > > > [ 409.948588] RAX: ffffffffffffffda RBX: 00007f9d32ade6a0 RCX: 00007f9d31b9b8d7 > > > [ 409.955719] RDX: 00007ffe4cae0df0 RSI: 000000000000b680 RDI: 0000000000000003 > > > [ 409.962852] RBP: 0000000000000003 R08: 00007f9d2b70a177 R09: 00007ffe4cae0e40 > > > [ 409.969984] R10: 00007ffe4cae0160 R11: 0000000000000202 R12: 00007ffe4cae0df0 > > > [ 409.977115] R13: 000000000000b680 R14: 0000000000000000 R15: 00007ffe4cae0f60 > > > > > > Signed-off-by: Scott Wood > > > Acked-by: Wu Hao > > > Acked-by: Alan Tull > > > Signed-off-by: Greg Kroah-Hartman > > > Signed-off-by: Sasha Levin > > > --- > > > drivers/fpga/dfl.c | 16 +++++++++++++++- > > > 1 file changed, 15 insertions(+), 1 deletion(-) > > > > Adding lockdep stuff is not really needed for stable kernels, please > > drop this from all trees. > > For actual splats? Why? I treat them as compiler warnings. Keeping these > around will just make them show up over and over in testing (at least > until we unify our testing story...). Ah, good point, ok, leave this in :) thanks, greg k-h