From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753878Ab1IUSKa (ORCPT ); Wed, 21 Sep 2011 14:10:30 -0400 Received: from mail-gx0-f174.google.com ([209.85.161.174]:33181 "EHLO mail-gx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753848Ab1IUSK1 (ORCPT ); Wed, 21 Sep 2011 14:10:27 -0400 Subject: [PATCH] acpi: Fix possible recursive locking in hwregs.c From: Rakib Mullick To: linux-kernel@vger.kernel.org Cc: Len Brown , Andrew Morton , linux-acpi@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Date: Thu, 22 Sep 2011 00:09:49 +0600 Message-ID: <1316628589.7341.11.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.32.1 (2.32.1-1.fc14) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Calling pm-suspend might trigger a recursive lock in it's code path. In function acpi_hw_clear_acpi_status, acpi_os_release_lock holds the lock acpi_gbl_hardware_lock before calling acpi_hw_register_write(), then without releasing acpi_gbl_hardware_lock, this function calls acpi_ev_walk_gpe_list, which also tries to hold acpi_gbl_hardware_lock and thus causes possible recursive lock. Following patch fixes this scenario by just releasing acpi_gbl_hardware_lock before calling acpi_ev_walk_gpe_list. [This patch was created against 3.0-rc3. Since kernel.org is down, I don't have the updated tree. So, before applying it might require some adjustment.] Signed-off-by: Rakib Mullick --- diff --git a/drivers/acpi/acpica/hwregs.c b/drivers/acpi/acpica/hwregs.c index 55accb7..e3110ac 100644 --- a/drivers/acpi/acpica/hwregs.c +++ b/drivers/acpi/acpica/hwregs.c @@ -269,6 +269,9 @@ acpi_status acpi_hw_clear_acpi_status(void) status = acpi_hw_register_write(ACPI_REGISTER_PM1_STATUS, ACPI_BITMASK_ALL_FIXED_STATUS); + + acpi_os_release_lock(acpi_gbl_hardware_lock, lock_flags); + if (ACPI_FAILURE(status)) { goto unlock_and_exit; } @@ -278,7 +281,6 @@ acpi_status acpi_hw_clear_acpi_status(void) status = acpi_ev_walk_gpe_list(acpi_hw_clear_gpe_block, NULL); unlock_and_exit: - acpi_os_release_lock(acpi_gbl_hardware_lock, lock_flags); return_ACPI_STATUS(status); }