ACPI: Fix lockdep false positives in acpi_power_off() (07e49a7a) · Commits · 戴 / test

All ACPICA locks are allocated by the same function, acpi_os_create_lock(), with the help of a local variable called "lock". Thus, when lockdep is enabled, it uses "lock" as the name of all those locks and regards them as instances of the same lock, which causes it to report possible locking problems with them when there aren't any. To work around this problem, define acpi_os_create_lock() as a macro and make it pass its argument to spin_lock_init(), so that lockdep uses it as the name of the new lock. Define this macron in a Linux-specific file, to minimize the resulting modifications of the OS-independent ACPICA parts. This change is based on an earlier patch from Andrea Righi and it addresses a regression from 2.6.39 tracked as https://bugzilla.kernel.org/show_bug.cgi?id=38152 Signed-off-by:

Rafael J. Wysocki <rjw@sisk.pl> Reported-and-tested-by:

Borislav Petkov <bp@alien8.de> Tested-by:

Andrea Righi <andrea@betterlinux.com> Reviewed-by:

Florian Mickler <florian@mickler.org> Signed-off-by:

Len Brown <len.brown@intel.com>

drivers/acpi/osl.c

+0 −17

Original line number	Diff line number	Diff line
		@@ -1332,23 +1332,6 @@ int acpi_resources_are_enforced(void)
		}
		EXPORT_SYMBOL(acpi_resources_are_enforced);

		/*
		* Create and initialize a spinlock.
		*/
		acpi_status
		acpi_os_create_lock(acpi_spinlock *out_handle)
		{
		spinlock_t *lock;

		lock = ACPI_ALLOCATE(sizeof(spinlock_t));
		if (!lock)
		return AE_NO_MEMORY;
		spin_lock_init(lock);
		*out_handle = lock;

		return AE_OK;
		}

		/*
		* Deallocate the memory for a spinlock.
		*/

include/acpi/acpiosxf.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -98,8 +98,11 @@ acpi_os_table_override(struct acpi_table_header *existing_table,
		/*
		* Spinlock primitives
		*/

		#ifndef acpi_os_create_lock
		acpi_status
		acpi_os_create_lock(acpi_spinlock *out_handle);
		#endif

		void acpi_os_delete_lock(acpi_spinlock handle);

include/acpi/platform/aclinux.h

+18 −0

Original line number	Diff line number	Diff line
		@@ -159,6 +159,24 @@ static inline void acpi_os_acquire_object(acpi_cache_t cache)
		} while (0)
		#endif

		/*
		* When lockdep is enabled, the spin_lock_init() macro stringifies it's
		* argument and uses that as a name for the lock in debugging.
		* By executing spin_lock_init() in a macro the key changes from "lock" for
		* all locks to the name of the argument of acpi_os_create_lock(), which
		* prevents lockdep from reporting false positives for ACPICA locks.
		*/
		#define acpi_os_create_lock(__handle) \
		({ \
		spinlock_t lock = ACPI_ALLOCATE(sizeof(lock)); \
		\
		if (lock) { \
		*(__handle) = lock; \
		spin_lock_init(*(__handle)); \
		} \
		lock ? AE_OK : AE_NO_MEMORY; \
		})

		#endif /* __KERNEL__ */

		#endif /* __ACLINUX_H__ */

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