lkml.org 
[lkml]   [2011]   [Nov]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Subject[PATCH -v1] acpi: Fix possible recursive locking in hwregs.c
From
Date
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 <rakib.mullick@gmail.com>
Cc: Lin Ming <ming.m.lin@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Len Brown <len.brown@intel.com>
---
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);
}




\
 
 \ /
  Last update: 2011-11-03 11:51    [from the cache]
©2003-2011 Jasper Spaans