From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 138B028373; Fri, 28 Mar 2025 05:27:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.77.154.182 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743139677; cv=none; b=EWr+pEBWU43CTdsJITfI9sAWNJ6AxZ5/b5ZWbXOLgZuMXFl6uEA4wSgnFQrYy1stH2UnU+NJCdH/Tvkkijogk5FrIgh5KjksJk6uSYqjPp+T4VLmLxTAxwjEf51IIzWkmTBmh6jBtGzYSstsi5MPZ9q3DTWl7xhq2dIY+jBXMi8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743139677; c=relaxed/simple; bh=WBme0HkyRRbDQ8Leq+Bd79QqsRz7MTEZD4uciGXbfQQ=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=Czirl+cxcjfuhUcCqMPeF3/E6SLLSxvJVdMZ6xRF732IV/TtooPNmzDsCrRi36z1psjMhS/PFdA2LCw22N8VTPQDuKnnOTbYlkMUS3C3MS9eJmIqjz7/hL51u6XxsxIiHdSy5sYLSgXZG3Q2LyBtL2OSdZCQoqD8Pm4T+/B3QP0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com; spf=pass smtp.mailfrom=linux.microsoft.com; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b=IHxKW8M3; arc=none smtp.client-ip=13.77.154.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="IHxKW8M3" Received: from namjain-Virtual-Machine.mshome.net (unknown [167.220.238.203]) by linux.microsoft.com (Postfix) with ESMTPSA id 789272025649; Thu, 27 Mar 2025 22:27:51 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 789272025649 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1743139674; bh=/2fyyVl7aEx5o80jahY1lO4oF3T0nV2EB9vhYbdzV0Y=; h=From:To:Cc:Subject:Date:From; b=IHxKW8M3Q3RXYtVWRK5U/MJj/grBs37XoNfaVJalUddmFYUsW37RPPD4AsCLjf6J5 MBnHzeeQCk0UYmtC0SQTIws3aOd6VjcEDPC8RRriYegT1GpIsfyGhvSoJ43rzdogHf W8z4wZkOA9j7Lte/3NLjaAQthJy7vNmChE06/M0M= From: Naman Jain To: "K . Y . Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Greg Kroah-Hartman , Stephen Hemminger Cc: linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, stable@kernel.org, Saurabh Sengar , Michael Kelley , Naman Jain Subject: [PATCH v3 0/2] uio_hv_generic: Fix ring buffer sysfs creation path Date: Fri, 28 Mar 2025 10:57:43 +0530 Message-Id: <20250328052745.1417-1-namjain@linux.microsoft.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Hi, PFB change logs: Changes since v2: https://lore.kernel.org/all/20250318061558.3294-1-namjain@linux.microsoft.com/ Addressed Greg's comments: * Split the original patch into two. * Updated the commit message to explain the problem scenario. * Added comments for new APIs in the kerneldoc format. * Highlighted potential race conditions and explained why sysfs should not be created in the driver probe. * Made minor changes to how the sysfs_update_group return value is handled. Changes since v1: https://lore.kernel.org/all/20250225052001.2225-1-namjain@linux.microsoft.com/ * Fixed race condition in setting channel->mmap_ring_buffer by introducing a new variable for visibility of sysfs (addressed Greg's comments) * Used binary attribute fields instead of regular ones for initializing attribute_group. * Make size of ring sysfs dynamic based on actual ring buffer's size. * Preferred to keep mmap function in uio_hv_generic to give more control over ring's mmap functionality, since this is specific to uio_hv_generic driver. * Remove spurious warning during sysfs creation in uio_hv_generic probe. * Added comments in a couple of places. Changes since RFC patch: https://lore.kernel.org/all/20250214064351.8994-1-namjain@linux.microsoft.com/ * Different approach to solve the problem is proposed (credits to Michael Kelley). * Core logic for sysfs creation moved out of uio_hv_generic, to VMBus drivers where rest of the sysfs attributes for a VMBus channel are defined. (addressed Greg's comments) * Used attribute groups instead of sysfs_create* functions, and bundled ring attribute with other attributes for the channel sysfs. Error logs: [ 35.574120] ------------[ cut here ]------------ [ 35.574122] WARNING: CPU: 0 PID: 10 at fs/sysfs/file.c:591 sysfs_create_bin_file+0x81/0x90 [ 35.574168] Workqueue: hv_pri_chan vmbus_add_channel_work [ 35.574172] RIP: 0010:sysfs_create_bin_file+0x81/0x90 [ 35.574197] Call Trace: [ 35.574199] [ 35.574200] ? show_regs+0x69/0x80 [ 35.574217] ? __warn+0x8d/0x130 [ 35.574220] ? sysfs_create_bin_file+0x81/0x90 [ 35.574222] ? report_bug+0x182/0x190 [ 35.574225] ? handle_bug+0x5b/0x90 [ 35.574244] ? exc_invalid_op+0x19/0x70 [ 35.574247] ? asm_exc_invalid_op+0x1b/0x20 [ 35.574252] ? sysfs_create_bin_file+0x81/0x90 [ 35.574255] hv_uio_probe+0x1e7/0x410 [uio_hv_generic] [ 35.574271] vmbus_probe+0x3b/0x90 [ 35.574275] really_probe+0xf4/0x3b0 [ 35.574279] __driver_probe_device+0x8a/0x170 [ 35.574282] driver_probe_device+0x23/0xc0 [ 35.574285] __device_attach_driver+0xb5/0x140 [ 35.574288] ? __pfx___device_attach_driver+0x10/0x10 [ 35.574291] bus_for_each_drv+0x86/0xe0 [ 35.574294] __device_attach+0xc1/0x200 [ 35.574297] device_initial_probe+0x13/0x20 [ 35.574315] bus_probe_device+0x99/0xa0 [ 35.574318] device_add+0x647/0x870 [ 35.574320] ? hrtimer_init+0x28/0x70 [ 35.574323] device_register+0x1b/0x30 [ 35.574326] vmbus_device_register+0x83/0x130 [ 35.574328] vmbus_add_channel_work+0x135/0x1a0 [ 35.574331] process_one_work+0x177/0x340 [ 35.574348] worker_thread+0x2b2/0x3c0 [ 35.574350] kthread+0xe3/0x1f0 [ 35.574353] ? __pfx_worker_thread+0x10/0x10 [ 35.574356] ? __pfx_kthread+0x10/0x10 Regards, Naman Naman Jain (2): uio_hv_generic: Fix sysfs creation path for ring buffer Drivers: hv: Make the sysfs node size for the ring buffer dynamic drivers/hv/hyperv_vmbus.h | 6 ++ drivers/hv/vmbus_drv.c | 119 ++++++++++++++++++++++++++++++++++- drivers/uio/uio_hv_generic.c | 33 ++++------ include/linux/hyperv.h | 6 ++ 4 files changed, 143 insertions(+), 21 deletions(-) base-commit: db8da9da41bced445077925f8a886c776a47440c -- 2.34.1