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 E02F72DFA42; Tue, 15 Apr 2025 15:10:49 +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=1744729850; cv=none; b=TT/DjaKSXSh4WII6c3XLAFh5FPHpV20Cn81du7g3SwmIggzNWXIShix5t65lpgzFQA2eNBb9Lf3bO/xpmxIRIDNxqnCixDrqaXWqtXwgoggAAv1rRxsZreJs+bsAoW2SpXfCQstK402WPy2JwHCsyHe00qIWvE7qIUiS/A9Incg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744729850; c=relaxed/simple; bh=O+gwOnhjyavqaM35YyMh2F8kVk/KcS+8tNTxAAWr0Mk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=bl6DSrNpApYil+TzW7/MaN/S6S2XXi2NUVVSDanEa7+M1bzQLRaAqDhRCV/Ujlb84rmrzVNkUi02uAYx9daWBR7HAYLHfTn1ZRyQ0RYd/lPRRCXWzcfOR8HqrBXDDDtDSqpuVVLGxHSmdS5+a4Uc/s/9Mzud2fbuhJdmRtuLWzU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=P940ouPD; 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="P940ouPD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B02E5C4CEEB; Tue, 15 Apr 2025 15:10:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1744729849; bh=O+gwOnhjyavqaM35YyMh2F8kVk/KcS+8tNTxAAWr0Mk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=P940ouPD+MZr2C5qxy3lHq5NBKN7P7A7hSOdkf6CzUeXgRvKOVSlb0CK3+XHb6Jmh 8S/FGaO2Gq1cpqzC83dTmDGEs6qRJ32cv5z9ar+ZssVU5ISpe+5JKdMzcD4Hqdl3cp 7DLaSeGWolA6BgtXfIA5IHSZdFoZsqYyy4KpIoNQ= Date: Tue, 15 Apr 2025 17:10:46 +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: <2025041527-cesarean-facial-cdca@gregkh> References: <20250410060847.82407-1-namjain@linux.microsoft.com> <20250410060847.82407-2-namjain@linux.microsoft.com> 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: <20250410060847.82407-2-namjain@linux.microsoft.com> 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 :(