[lkml]   [2011]   [Sep]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[PATCH] acpi: Fix possible recursive locking in hwregs.c
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 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_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);

- acpi_os_release_lock(acpi_gbl_hardware_lock, lock_flags);

 \ /
  Last update: 2011-09-21 20:13    [W:0.037 / U:7.400 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site