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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no 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 9963DC2BA83 for ; Thu, 13 Feb 2020 18:04:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 78630206DB for ; Thu, 13 Feb 2020 18:04:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581617040; bh=RIhL3zsLAIZ5zP3Wo96HWL5tMetMRisfM3MVee1hCtA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=zcSdV8N8JF9MzFJhuVmh/a2fDSuzGwjv+cryXMOq6UO+hUT9S9DjJ178viFYbZ94w IP7vwIAuZPfJW+Gd++IYnXTbwpVr77IvHKEq6nKRkNwo+5guZEPabk5O4wPvEeIr8H kHeyzJnNaHKHDVYFSFp8F2dH4tEN7sXhPxyCQKU0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726282AbgBMSEA (ORCPT ); Thu, 13 Feb 2020 13:04:00 -0500 Received: from mail.kernel.org ([198.145.29.99]:34576 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725781AbgBMSD7 (ORCPT ); Thu, 13 Feb 2020 13:03:59 -0500 Received: from localhost (unknown [213.57.247.131]) (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 D049B217F4; Thu, 13 Feb 2020 18:03:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581617039; bh=RIhL3zsLAIZ5zP3Wo96HWL5tMetMRisfM3MVee1hCtA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=PSKUgB/kn+hXYENPJ3jIAZooPzLF/5Viima3m8AAcE7RtxZb9cAhffDIkbgICgHHD QLmisrVdVPnJtojmgG4KCLZP4/R7yIjWj/gd0wLs8cjT08wI44u4tKfOqAk7//LQ/t nmpRK4qA1vBUmn+rNpyQqlBfueDSXjY5QXCCwfJA= Date: Thu, 13 Feb 2020 20:03:55 +0200 From: Leon Romanovsky To: Jason Gunthorpe Cc: Doug Ledford , RDMA mailing list , Daniel Jurgens , Erez Shitrit , Maor Gottlieb , Michael Guralnik , Moni Shoua , Parav Pandit , Sean Hefty , Valentine Fatiev , Yishai Hadas , Yonatan Cohen , Zhu Yanjun Subject: Re: [PATCH rdma-rc 8/9] IB/umad: Fix kernel crash while unloading ib_umad Message-ID: <20200213180355.GF679970@unreal> References: <20200212072635.682689-1-leon@kernel.org> <20200212072635.682689-9-leon@kernel.org> <20200213142818.GA16120@ziepe.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200213142818.GA16120@ziepe.ca> Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Thu, Feb 13, 2020 at 10:28:18AM -0400, Jason Gunthorpe wrote: > On Wed, Feb 12, 2020 at 09:26:34AM +0200, Leon Romanovsky wrote: > > From: Yonatan Cohen > > > > When unloading ib_umad, remove ibdev sys file 1st before > > port removal to prevent kernel oops. > > > > ib_mad's method ibdev_show() might access a umad port > > whoes ibdev field has already been NULLed when rmmod ib_umad > > was issued from another shell. > > > > Consider this scenario > > shell-1 shell-2 > > rmmod ib_mod cat /sys/devices/../ibdev > > | | > > ib_umad_kill_port() ibdev_show() > > port->ib_dev = NULL dev_name(port->ib_dev) > > > > kernel stack > > PF: error_code(0x0000) - not-present page > > Oops: 0000 [#1] SMP DEBUG_PAGEALLOC PTI > > RIP: 0010:ibdev_show+0x18/0x50 [ib_umad] > > RSP: 0018:ffffc9000097fe40 EFLAGS: 00010282 > > RAX: 0000000000000000 RBX: ffffffffa0441120 RCX: ffff8881df514000 > > RDX: ffff8881df514000 RSI: ffffffffa0441120 RDI: ffff8881df1e8870 > > RBP: ffffffff81caf000 R08: ffff8881df1e8870 R09: 0000000000000000 > > R10: 0000000000001000 R11: 0000000000000003 R12: ffff88822f550b40 > > R13: 0000000000000001 R14: ffffc9000097ff08 R15: ffff8882238bad58 > > FS: 00007f1437ff3740(0000) GS:ffff888236940000(0000) knlGS:0000000000000000 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: 00000000000004e8 CR3: 00000001e0dfc001 CR4: 00000000001606e0 > > Call Trace: > > dev_attr_show+0x15/0x50 > > sysfs_kf_seq_show+0xb8/0x1a0 > > seq_read+0x12d/0x350 > > vfs_read+0x89/0x140 > > ksys_read+0x55/0xd0 > > do_syscall_64+0x55/0x1b0 > > entry_SYSCALL_64_after_hwframe+0x44/0xa9: > > > > Fixes: e9dd5daf884c ("IB/umad: Refactor code to use cdev_device_add()") > > This is the wrong fixes line, this ordering change was actually > deliberately done: > Can you please fix the fixes line, so I will resend unaccepted patches only? Thanks