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authorRakib Mullick <rakib.mullick@gmail.com>2011-11-06 21:18:17 +0600
committerLen Brown <len.brown@intel.com>2011-11-06 20:09:23 -0500
commitf7f71cfbf0c276ee3d8d856d0f35a41aed997fa4 (patch)
tree946537396845cdda9f4b9803d27c577d3566901e /drivers/acpi
parentc3b92c8787367a8bb53d57d9789b558f1295cc96 (diff)
downloadlinux-f7f71cfbf0c276ee3d8d856d0f35a41aed997fa4.tar.bz2
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_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. Both acpi_gbl_hardware_lock and acpi_gbl_gpe_lock are at same lock-class and which might cause lock recursion deadlock. 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. Changes since v1 (https://lkml.org/lkml/2011/11/3/89): - Update changelog and rename goto label, courtesy Srivatsa S. Bhat. Signed-off-by: Rakib Mullick <rakib.mullick@gmail.com> Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Acked-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'drivers/acpi')
-rw-r--r--drivers/acpi/acpica/hwregs.c11
1 files changed, 6 insertions, 5 deletions
diff --git a/drivers/acpi/acpica/hwregs.c b/drivers/acpi/acpica/hwregs.c
index 55accb7018bb..cc70f3fdcdd1 100644
--- a/drivers/acpi/acpica/hwregs.c
+++ b/drivers/acpi/acpica/hwregs.c
@@ -269,16 +269,17 @@ acpi_status acpi_hw_clear_acpi_status(void)
status = acpi_hw_register_write(ACPI_REGISTER_PM1_STATUS,
ACPI_BITMASK_ALL_FIXED_STATUS);
- if (ACPI_FAILURE(status)) {
- goto unlock_and_exit;
- }
+
+ acpi_os_release_lock(acpi_gbl_hardware_lock, lock_flags);
+
+ if (ACPI_FAILURE(status))
+ goto exit;
/* Clear the GPE Bits in all GPE registers in all GPE blocks */
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);
+exit:
return_ACPI_STATUS(status);
}