From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757827Ab2IDWGO (ORCPT ); Tue, 4 Sep 2012 18:06:14 -0400 Received: from usindpps03.hds.com ([207.126.252.16]:58414 "EHLO usindpps03.hds.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752496Ab2IDWGN convert rfc822-to-8bit (ORCPT ); Tue, 4 Sep 2012 18:06:13 -0400 From: Seiji Aguchi To: Mike Waychison , "linux-kernel@vger.kernel.org" , "Luck, Tony (tony.luck@intel.com)" , "Matthew Garrett (mjg@redhat.com)" , "dzickus@redhat.com" , "linux-efi@vger.kernel.org" CC: "dle-develop@lists.sourceforge.net" , Satoru Moriya Subject: [RESEND][PATCH v4 0/3] make efivars/efi_pstore interrupt-safe Thread-Topic: [RESEND][PATCH v4 0/3] make efivars/efi_pstore interrupt-safe Thread-Index: Ac2K54VYIT+D1QatRhGlRDeIAxe21Q== Date: Tue, 4 Sep 2012 22:05:54 +0000 Message-ID: Accept-Language: ja-JP, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.74.43.113] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:5.7.7855,1.0.431,0.0.0000 definitions=2012-09-04_07:2012-09-04,2012-09-04,1970-01-01 signatures=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Changelog v3 -> v4 - Patch 2/3 Move cancel_work_sync() above an efi_enabled test in efivars_exit(). v2 -> v3 - Patch 1/3 Replace spin_lock_irqsave/spin_unlock_irqrestore with spin_lock_irq/spin_unlock_irq in efivars_unregister(), efivar_create(), efivar_store_raw() and efivar_delete() which are called in a process context. - Patch 2/3 Change a name of delete_sysfs_entry() to delete_all_stale_sysfs_entries(). Also, don't release an efivar->lock while searching efivar->list in delete_all_stale_sysfs_entries(). - Patch 3/3 Remove a logic in efi_pstore_erase() which freshly created in patch v2. v1 -> v2 - Patch 1/3 Add spin_lock_irq/spin_unlock_irq to open/close callbacks of efi_pstore instead of moving spin_locks to a read callback. - Patch 2/3 Replace a periodical timer with schedule_work(). - Patch 3/3 freshly create to kick a workqueue in oops case only. [Problem] There are following problems related to an interrupt context in efivar/efi_pstore. Currently, efivars enables interrupt while taking efivars->lock. So, there is a risk to be deadlocking in a write callback of efi_pstore if kernel panics in interrupt context while taking efi_lock. Also, efi_pstore creates sysfs entries ,which enable users to access to NVRAM, in a write callback. If a kernel panic happens in interrupt contexts, pstore may fail because it could sleep due to dynamic memory allocations during creating sysfs entries. To resolve the problems above, a goal of this patchset is making efivars/efi_pstore interrupt-safe. [Patch Description] Patch 1/3 efivars: Disable external interrupt while holding efivars->lock This patch replaces spin_lock/spin_unlock with spin_lock_irqsave/spin_lock_irqrestore to make efivars interrupt safe Patch 2/3 efi_pstore: Introducing workqueue updating sysfs entries This patch removes sysfs operations from write callback by introducing a workqueue updating sysfs entries Patch 3/3 efi_pstore: Skiping scheduling a workqueue in cases other than oops This patch restricts a schedule of a workqueue in case where users erase entries or oops happen which is truly needed for users. drivers/firmware/efivars.c | 167 +++++++++++++++++++++++++++++++++++-------- include/linux/efi.h | 3 +- 2 files changed, 138 insertions(+), 32 deletions(-)