From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5BBEF2980AE; Tue, 15 Apr 2025 16:14:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744733646; cv=none; b=hocZatx/62V72OHoDapjxNgiReUIXSfUmDqyeXQKx7cQ3EPHcxjybShFi0xVqBQdDQHPMhfgSavNd10O8p3nQXLQrWFKCiSV9c/NddJkDgp/pWD7y0Mukthtns23MsOiH4ncwSMNxFHX8MrIhVqn8wQg4AR6h/ZujGZ8fB+zXYI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744733646; c=relaxed/simple; bh=NbLare3beq/jAIFXidoKTYfv9DNLJVjdI7gHvGUkNMc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=o/vTaJ1XruiS+Y2R94u9PfqUahi4vjWUIrCUVDcDFDndKBTN/yx9AB/gDZMtL1p2NJ/Gxx35tgECHiYxdsh62eew0xHnZEMRKcCQLFGLkszYVHieenp1psBB2wO2VBnFfaR3gA0oAyQNdd7X18vwbTKY/tQN2mjYWhwh1ISWJXI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=zx8vlGfH; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="zx8vlGfH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3E101C4CEEB; Tue, 15 Apr 2025 16:14:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1744733645; bh=NbLare3beq/jAIFXidoKTYfv9DNLJVjdI7gHvGUkNMc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=zx8vlGfH2I/rlgiziU5fVTIr66F9GJh02lbq3Va1r3zFay17UCDwHkqJ4E1V6yNc0 Q2RY8CEhGVMV85Kl7T4+XUWWkPCtzGQ7obLejfg/VQB0NJALOHEfaD4VVwxk6bknmo vmp2AAW6W9G3yEeTehzE+q9r/td4vf4C38457/AA= Date: Tue, 15 Apr 2025 18:14:02 +0200 From: Greg Kroah-Hartman To: Naman Jain Cc: "K . Y . Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Stephen Hemminger , linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, stable@kernel.org, Saurabh Sengar , Michael Kelley Subject: Re: [PATCH v4 1/2] uio_hv_generic: Fix sysfs creation path for ring buffer Message-ID: <2025041549-unawake-frisbee-5813@gregkh> References: <20250410060847.82407-1-namjain@linux.microsoft.com> <20250410060847.82407-2-namjain@linux.microsoft.com> <2025041527-cesarean-facial-cdca@gregkh> Precedence: bulk X-Mailing-List: linux-hyperv@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Apr 15, 2025 at 09:24:16PM +0530, Naman Jain wrote: > > > On 4/15/2025 8:40 PM, Greg Kroah-Hartman wrote: > > On Thu, Apr 10, 2025 at 11:38:46AM +0530, Naman Jain wrote: > > > On regular bootup, devices get registered to VMBus first, so when > > > uio_hv_generic driver for a particular device type is probed, > > > the device is already initialized and added, so sysfs creation in > > > uio_hv_generic probe works fine. However, when device is removed > > > and brought back, the channel rescinds and device again gets > > > registered to VMBus. However this time, the uio_hv_generic driver is > > > already registered to probe for that device and in this case sysfs > > > creation is tried before the device's kobject gets initialized > > > completely. > > > > > > Fix this by moving the core logic of sysfs creation for ring buffer, > > > from uio_hv_generic to HyperV's VMBus driver, where rest of the sysfs > > > attributes for the channels are defined. While doing that, make use > > > of attribute groups and macros, instead of creating sysfs directly, > > > to ensure better error handling and code flow. > > > > > > Problem path: > > > vmbus_process_offer (new offer comes for the VMBus device) > > > vmbus_add_channel_work > > > vmbus_device_register > > > |-> device_register > > > | |... > > > | |-> hv_uio_probe > > > | |... > > > | |-> sysfs_create_bin_file (leads to a warning as > > > | primary channel's kobject, which is used to > > > | create sysfs is not yet initialized) > > > |-> kset_create_and_add > > > |-> vmbus_add_channel_kobj (initialization of primary channel's > > > kobject happens later) > > > > > > Above code flow is sequential and the warning is always reproducible in > > > this path. > > > > > > Fixes: 9ab877a6ccf8 ("uio_hv_generic: make ring buffer attribute for primary channel") > > > Cc: stable@kernel.org > > > Suggested-by: Saurabh Sengar > > > Suggested-by: Michael Kelley > > > Signed-off-by: Naman Jain > > > --- > > > drivers/hv/hyperv_vmbus.h | 6 ++ > > > drivers/hv/vmbus_drv.c | 110 ++++++++++++++++++++++++++++++++++- > > > drivers/uio/uio_hv_generic.c | 39 ++++++------- > > > include/linux/hyperv.h | 6 ++ > > > 4 files changed, 138 insertions(+), 23 deletions(-) > > > > Always run checkpatch on a patch before submitting it for review :( > > > > Hi Greg, > I verified again and I could not see checkpatch warnings with patch 1,2. > There was a warning regarding length of characters for link to previous > versions in the cover letter but I ignored it. > > I tried on latest linux-next tip with this series fetched from lore using > b4. I'm sorry, if I am missing something, but can you please try again. I've pointed out the first thing that I noticed, thanks.