From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rakib Mullick Subject: [PATCH -v1] acpi: Fix possible recursive locking in hwregs.c Date: Thu, 03 Nov 2011 16:48:42 +0600 Message-ID: <1320317323.5711.5.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-gy0-f174.google.com ([209.85.160.174]:33455 "EHLO mail-gy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932159Ab1KCKtA (ORCPT ); Thu, 3 Nov 2011 06:49:00 -0400 Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: linux-kernel@vger.kernel.org Cc: linux-acpi , Andrew Morton , Len Brown , Lin Ming Calling pm-suspend might trigger a recursive lock in it's code path. In function acpi_hw_clear_acpi_status, acpi_os_acquire_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 tries to hold acpi_gbl_gpe_lock and thus might causes possible recursive lock. Following patch fixes this scenario by just releasing acpi_gbl_hardware_lock before calling acpi_ev_walk_gpe_list. Changes since v0(https://lkml.org/lkml/2011/9/21/355): - Fix changelog, thanks to Lin Ming. Signed-off-by: Rakib Mullick Cc: Lin Ming Cc: Andrew Morton Cc: Len Brown --- 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); }