linux_dsm_epyc7002/kernel/locking
Imre Deak d9349850e1 locking/lockdep: Fix merging of hlocks with non-zero references
The sequence

	static DEFINE_WW_CLASS(test_ww_class);

	struct ww_acquire_ctx ww_ctx;
	struct ww_mutex ww_lock_a;
	struct ww_mutex ww_lock_b;
	struct ww_mutex ww_lock_c;
	struct mutex lock_c;

	ww_acquire_init(&ww_ctx, &test_ww_class);

	ww_mutex_init(&ww_lock_a, &test_ww_class);
	ww_mutex_init(&ww_lock_b, &test_ww_class);
	ww_mutex_init(&ww_lock_c, &test_ww_class);

	mutex_init(&lock_c);

	ww_mutex_lock(&ww_lock_a, &ww_ctx);

	mutex_lock(&lock_c);

	ww_mutex_lock(&ww_lock_b, &ww_ctx);
	ww_mutex_lock(&ww_lock_c, &ww_ctx);

	mutex_unlock(&lock_c);	(*)

	ww_mutex_unlock(&ww_lock_c);
	ww_mutex_unlock(&ww_lock_b);
	ww_mutex_unlock(&ww_lock_a);

	ww_acquire_fini(&ww_ctx); (**)

will trigger the following error in __lock_release() when calling
mutex_release() at **:

	DEBUG_LOCKS_WARN_ON(depth <= 0)

The problem is that the hlock merging happening at * updates the
references for test_ww_class incorrectly to 3 whereas it should've
updated it to 4 (representing all the instances for ww_ctx and
ww_lock_[abc]).

Fix this by updating the references during merging correctly taking into
account that we can have non-zero references (both for the hlock that we
merge into another hlock or for the hlock we are merging into).

Signed-off-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Link: https://lkml.kernel.org/r/20190524201509.9199-2-imre.deak@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-06-03 12:32:56 +02:00
..
lock_events_list.h locking/rwsem: Enable lock event counting 2019-04-10 10:56:06 +02:00
lock_events.c locking/lock_events: Don't show pvqspinlock events on bare metal 2019-04-10 10:56:05 +02:00
lock_events.h locking/lock_events: Use this_cpu_add() when necessary 2019-05-24 14:17:18 -07:00
lockdep_internals.h locking/lockdep: Test all incompatible scenarios at once in check_irq_usage() 2019-04-29 08:29:20 +02:00
lockdep_proc.c locking/lockdep: Introduce lockdep_next_lockchain() and lock_chain_count() 2019-02-28 07:55:44 +01:00
lockdep_states.h locking/lockdep: Rework FS_RECLAIM annotation 2017-08-10 12:29:03 +02:00
lockdep.c locking/lockdep: Fix merging of hlocks with non-zero references 2019-06-03 12:32:56 +02:00
locktorture.c locktorture: NULL cxt.lwsa and cxt.lrsa to allow bad-arg detection 2019-03-26 14:42:53 -07:00
Makefile locking/lock_events: Make lock_events available for all archs & other locks 2019-04-10 10:56:04 +02:00
mcs_spinlock.h locking/mcs: Use smp_cond_load_acquire() in MCS spin loop 2018-04-27 09:48:49 +02:00
mutex-debug.c locking/mutex: Replace spin_is_locked() with lockdep 2018-11-12 09:06:22 -08:00
mutex-debug.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mutex.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
mutex.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
osq_lock.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
percpu-rwsem.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
qrwlock.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00
qspinlock_paravirt.h locking/qspinlock_stat: Introduce generic lockevent_*() counting APIs 2019-04-10 10:56:03 +02:00
qspinlock_stat.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00
qspinlock.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00
rtmutex_common.h locking/rtmutex: Handle non enqueued waiters gracefully in remove_waiter() 2018-03-28 23:01:30 +02:00
rtmutex-debug.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
rtmutex-debug.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
rtmutex.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
rtmutex.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
rwsem-xadd.c locking/rwsem: Prevent decrement of reader count before increment 2019-05-07 08:46:46 +02:00
rwsem.c locking/rwsem: Enhance DEBUG_RWSEMS_WARN_ON() macro 2019-04-10 10:56:03 +02:00
rwsem.h locking/rwsem: Prevent unneeded warning during locking selftest 2019-04-14 11:09:35 +02:00
semaphore.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/debug.h> 2017-03-02 08:42:34 +01:00
spinlock_debug.c mmiowb: Hook up mmiowb helpers to spinlocks and generic I/O accessors 2019-04-08 11:59:47 +01:00
spinlock.c asm-generic/mmiowb: Add generic implementation of mmiowb() tracking 2019-04-08 11:59:39 +01:00
test-ww_mutex.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 9 2019-05-21 11:28:40 +02:00