The patch titled
Subject: lglock: update lockdep annotations to report recursive local locks
has been added to the -mm tree. Its filename is
lglock-update-lockdep-annotations-to-report-recursive-local-locks.patch
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From: Michel Lespinasse <walken@xxxxxxxxxx>
Subject: lglock: update lockdep annotations to report recursive local locks
Oleg Nesterov recently noticed that the lockdep annotations in lglock.c
are not sufficient to detect some obvious deadlocks, such as
lg_local_lock(LOCK) + lg_local_lock(LOCK) or spin_lock(X) +
lg_local_lock(Y) vs lg_local_lock(Y) + spin_lock(X).
Both issues are easily fixed by indicating to lockdep that lglock's local
locks are not recursive. We shouldn't use the rwlock acquire/release
functions here, as lglock doesn't share the same semantics. Instead we
can base our lockdep annotations on the lock_acquire_shared (for local
lglock) and lock_acquire_exclusive (for global lglock) helpers.
I am not proposing new lglock specific helpers as I don't see the point of
the existing second level of helpers :)
Signed-off-by: Michel Lespinasse <walken@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>
Cc: "Srivatsa S. Bhat" <srivatsa.bhat@xxxxxxxxxxxxxxxxxx>
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/lglock.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff -puN kernel/lglock.c~lglock-update-lockdep-annotations-to-report-recursive-local-locks kernel/lglock.c
--- a/kernel/lglock.c~lglock-update-lockdep-annotations-to-report-recursive-local-locks
+++ a/kernel/lglock.c
@@ -21,7 +21,7 @@ void lg_local_lock(struct lglock *lg)
arch_spinlock_t *lock;
preempt_disable();
- rwlock_acquire_read(&lg->lock_dep_map, 0, 0, _RET_IP_);
+ lock_acquire_shared(&lg->lock_dep_map, 0, 0, NULL, _RET_IP_);
lock = this_cpu_ptr(lg->lock);
arch_spin_lock(lock);
}
@@ -31,7 +31,7 @@ void lg_local_unlock(struct lglock *lg)
{
arch_spinlock_t *lock;
- rwlock_release(&lg->lock_dep_map, 1, _RET_IP_);
+ lock_release(&lg->lock_dep_map, 1, _RET_IP_);
lock = this_cpu_ptr(lg->lock);
arch_spin_unlock(lock);
preempt_enable();
@@ -43,7 +43,7 @@ void lg_local_lock_cpu(struct lglock *lg
arch_spinlock_t *lock;
preempt_disable();
- rwlock_acquire_read(&lg->lock_dep_map, 0, 0, _RET_IP_);
+ lock_acquire_shared(&lg->lock_dep_map, 0, 0, NULL, _RET_IP_);
lock = per_cpu_ptr(lg->lock, cpu);
arch_spin_lock(lock);
}
@@ -53,7 +53,7 @@ void lg_local_unlock_cpu(struct lglock *
{
arch_spinlock_t *lock;
- rwlock_release(&lg->lock_dep_map, 1, _RET_IP_);
+ lock_release(&lg->lock_dep_map, 1, _RET_IP_);
lock = per_cpu_ptr(lg->lock, cpu);
arch_spin_unlock(lock);
preempt_enable();
@@ -65,7 +65,7 @@ void lg_global_lock(struct lglock *lg)
int i;
preempt_disable();
- rwlock_acquire(&lg->lock_dep_map, 0, 0, _RET_IP_);
+ lock_acquire_exclusive(&lg->lock_dep_map, 0, 0, NULL, _RET_IP_);
for_each_possible_cpu(i) {
arch_spinlock_t *lock;
lock = per_cpu_ptr(lg->lock, i);
@@ -78,7 +78,7 @@ void lg_global_unlock(struct lglock *lg)
{
int i;
- rwlock_release(&lg->lock_dep_map, 1, _RET_IP_);
+ lock_release(&lg->lock_dep_map, 1, _RET_IP_);
for_each_possible_cpu(i) {
arch_spinlock_t *lock;
lock = per_cpu_ptr(lg->lock, i);
_
Patches currently in -mm which might be from walken@xxxxxxxxxx are
mm-remove-free_area_cache-use-in-powerpc-architecture.patch
mm-use-vm_unmapped_area-on-powerpc-architecture.patch
lockdep-introduce-lock_acquire_exclusive-shared-helper-macros.patch
lglock-update-lockdep-annotations-to-report-recursive-local-locks.patch
mm-remove-free_area_cache.patch
mutex-subsystem-synchro-test-module.patch
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