From f7f71cfbf0c276ee3d8d856d0f35a41aed997fa4 Mon Sep 17 00:00:00 2001 From: Rakib Mullick Date: Sun, 6 Nov 2011 21:18:17 +0600 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_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 Reviewed-by: Srivatsa S. Bhat Acked-by: Rafael J. Wysocki Signed-off-by: Len Brown --- drivers/acpi/acpica/hwregs.c | 11 ++++++----- 1 file 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); } -- 2.20.1