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authorLinus Torvalds <torvalds@linux-foundation.org>2017-11-13 12:38:26 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-11-13 12:38:26 -0800
commit8e9a2dba8686187d8c8179e5b86640e653963889 (patch)
treea4ba543649219cbb28d91aab65b785d763f5d069 /lib
parent6098850e7e6978f95a958f79a645a653228d0002 (diff)
parent450cbdd0125cfa5d7bbf9e2a6b6961cc48d29730 (diff)
downloadlinux-8e9a2dba8686187d8c8179e5b86640e653963889.tar.bz2
Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull core locking updates from Ingo Molnar: "The main changes in this cycle are: - Another attempt at enabling cross-release lockdep dependency tracking (automatically part of CONFIG_PROVE_LOCKING=y), this time with better performance and fewer false positives. (Byungchul Park) - Introduce lockdep_assert_irqs_enabled()/disabled() and convert open-coded equivalents to lockdep variants. (Frederic Weisbecker) - Add down_read_killable() and use it in the VFS's iterate_dir() method. (Kirill Tkhai) - Convert remaining uses of ACCESS_ONCE() to READ_ONCE()/WRITE_ONCE(). Most of the conversion was Coccinelle driven. (Mark Rutland, Paul E. McKenney) - Get rid of lockless_dereference(), by strengthening Alpha atomics, strengthening READ_ONCE() with smp_read_barrier_depends() and thus being able to convert users of lockless_dereference() to READ_ONCE(). (Will Deacon) - Various micro-optimizations: - better PV qspinlocks (Waiman Long), - better x86 barriers (Michael S. Tsirkin) - better x86 refcounts (Kees Cook) - ... plus other fixes and enhancements. (Borislav Petkov, Juergen Gross, Miguel Bernal Marin)" * 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (70 commits) locking/x86: Use LOCK ADD for smp_mb() instead of MFENCE rcu: Use lockdep to assert IRQs are disabled/enabled netpoll: Use lockdep to assert IRQs are disabled/enabled timers/posix-cpu-timers: Use lockdep to assert IRQs are disabled/enabled sched/clock, sched/cputime: Use lockdep to assert IRQs are disabled/enabled irq_work: Use lockdep to assert IRQs are disabled/enabled irq/timings: Use lockdep to assert IRQs are disabled/enabled perf/core: Use lockdep to assert IRQs are disabled/enabled x86: Use lockdep to assert IRQs are disabled/enabled smp/core: Use lockdep to assert IRQs are disabled/enabled timers/hrtimer: Use lockdep to assert IRQs are disabled/enabled timers/nohz: Use lockdep to assert IRQs are disabled/enabled workqueue: Use lockdep to assert IRQs are disabled/enabled irq/softirqs: Use lockdep to assert IRQs are disabled/enabled locking/lockdep: Add IRQs disabled/enabled assertion APIs: lockdep_assert_irqs_enabled()/disabled() locking/pvqspinlock: Implement hybrid PV queued/unfair locks locking/rwlocks: Fix comments x86/paravirt: Set up the virt_spin_lock_key after static keys get initialized block, locking/lockdep: Assign a lock_class per gendisk used for wait_for_completion() workqueue: Remove now redundant lock acquisitions wrt. workqueue flushes ...
Diffstat (limited to 'lib')
-rw-r--r--lib/Kconfig.debug19
-rw-r--r--lib/assoc_array.c20
-rw-r--r--lib/dynamic_queue_limits.c2
-rw-r--r--lib/llist.c2
-rw-r--r--lib/vsprintf.c4
5 files changed, 31 insertions, 16 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index dfdad67d8f6c..2b439a515c30 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1092,8 +1092,8 @@ config PROVE_LOCKING
select DEBUG_MUTEXES
select DEBUG_RT_MUTEXES if RT_MUTEXES
select DEBUG_LOCK_ALLOC
- select LOCKDEP_CROSSRELEASE if BROKEN
- select LOCKDEP_COMPLETIONS if BROKEN
+ select LOCKDEP_CROSSRELEASE
+ select LOCKDEP_COMPLETIONS
select TRACE_IRQFLAGS
default n
help
@@ -1179,6 +1179,21 @@ config LOCKDEP_COMPLETIONS
A deadlock caused by wait_for_completion() and complete() can be
detected by lockdep using crossrelease feature.
+config BOOTPARAM_LOCKDEP_CROSSRELEASE_FULLSTACK
+ bool "Enable the boot parameter, crossrelease_fullstack"
+ depends on LOCKDEP_CROSSRELEASE
+ default n
+ help
+ The lockdep "cross-release" feature needs to record stack traces
+ (of calling functions) for all acquisitions, for eventual later
+ use during analysis. By default only a single caller is recorded,
+ because the unwind operation can be very expensive with deeper
+ stack chains.
+
+ However a boot parameter, crossrelease_fullstack, was
+ introduced since sometimes deeper traces are required for full
+ analysis. This option turns on the boot parameter.
+
config DEBUG_LOCKDEP
bool "Lock dependency engine debugging"
depends on DEBUG_KERNEL && LOCKDEP
diff --git a/lib/assoc_array.c b/lib/assoc_array.c
index 4e53be8bc590..b77d51da8c73 100644
--- a/lib/assoc_array.c
+++ b/lib/assoc_array.c
@@ -39,7 +39,7 @@ begin_node:
/* Descend through a shortcut */
shortcut = assoc_array_ptr_to_shortcut(cursor);
smp_read_barrier_depends();
- cursor = ACCESS_ONCE(shortcut->next_node);
+ cursor = READ_ONCE(shortcut->next_node);
}
node = assoc_array_ptr_to_node(cursor);
@@ -55,7 +55,7 @@ begin_node:
*/
has_meta = 0;
for (; slot < ASSOC_ARRAY_FAN_OUT; slot++) {
- ptr = ACCESS_ONCE(node->slots[slot]);
+ ptr = READ_ONCE(node->slots[slot]);
has_meta |= (unsigned long)ptr;
if (ptr && assoc_array_ptr_is_leaf(ptr)) {
/* We need a barrier between the read of the pointer
@@ -89,7 +89,7 @@ continue_node:
smp_read_barrier_depends();
for (; slot < ASSOC_ARRAY_FAN_OUT; slot++) {
- ptr = ACCESS_ONCE(node->slots[slot]);
+ ptr = READ_ONCE(node->slots[slot]);
if (assoc_array_ptr_is_meta(ptr)) {
cursor = ptr;
goto begin_node;
@@ -98,7 +98,7 @@ continue_node:
finished_node:
/* Move up to the parent (may need to skip back over a shortcut) */
- parent = ACCESS_ONCE(node->back_pointer);
+ parent = READ_ONCE(node->back_pointer);
slot = node->parent_slot;
if (parent == stop)
return 0;
@@ -107,7 +107,7 @@ finished_node:
shortcut = assoc_array_ptr_to_shortcut(parent);
smp_read_barrier_depends();
cursor = parent;
- parent = ACCESS_ONCE(shortcut->back_pointer);
+ parent = READ_ONCE(shortcut->back_pointer);
slot = shortcut->parent_slot;
if (parent == stop)
return 0;
@@ -147,7 +147,7 @@ int assoc_array_iterate(const struct assoc_array *array,
void *iterator_data),
void *iterator_data)
{
- struct assoc_array_ptr *root = ACCESS_ONCE(array->root);
+ struct assoc_array_ptr *root = READ_ONCE(array->root);
if (!root)
return 0;
@@ -194,7 +194,7 @@ assoc_array_walk(const struct assoc_array *array,
pr_devel("-->%s()\n", __func__);
- cursor = ACCESS_ONCE(array->root);
+ cursor = READ_ONCE(array->root);
if (!cursor)
return assoc_array_walk_tree_empty;
@@ -220,7 +220,7 @@ consider_node:
slot = segments >> (level & ASSOC_ARRAY_KEY_CHUNK_MASK);
slot &= ASSOC_ARRAY_FAN_MASK;
- ptr = ACCESS_ONCE(node->slots[slot]);
+ ptr = READ_ONCE(node->slots[slot]);
pr_devel("consider slot %x [ix=%d type=%lu]\n",
slot, level, (unsigned long)ptr & 3);
@@ -294,7 +294,7 @@ follow_shortcut:
} while (sc_level < shortcut->skip_to_level);
/* The shortcut matches the leaf's index to this point. */
- cursor = ACCESS_ONCE(shortcut->next_node);
+ cursor = READ_ONCE(shortcut->next_node);
if (((level ^ sc_level) & ~ASSOC_ARRAY_KEY_CHUNK_MASK) != 0) {
level = sc_level;
goto jumped;
@@ -337,7 +337,7 @@ void *assoc_array_find(const struct assoc_array *array,
* the terminal node.
*/
for (slot = 0; slot < ASSOC_ARRAY_FAN_OUT; slot++) {
- ptr = ACCESS_ONCE(node->slots[slot]);
+ ptr = READ_ONCE(node->slots[slot]);
if (ptr && assoc_array_ptr_is_leaf(ptr)) {
/* We need a barrier between the read of the pointer
* and dereferencing the pointer - but only if we are
diff --git a/lib/dynamic_queue_limits.c b/lib/dynamic_queue_limits.c
index 6a406fafb5d6..da4672a50a54 100644
--- a/lib/dynamic_queue_limits.c
+++ b/lib/dynamic_queue_limits.c
@@ -21,7 +21,7 @@ void dql_completed(struct dql *dql, unsigned int count)
unsigned int ovlimit, completed, num_queued;
bool all_prev_completed;
- num_queued = ACCESS_ONCE(dql->num_queued);
+ num_queued = READ_ONCE(dql->num_queued);
/* Can't complete more than what's in queue */
BUG_ON(count > num_queued - dql->num_completed);
diff --git a/lib/llist.c b/lib/llist.c
index ae5872b1df0c..7062e931a7bb 100644
--- a/lib/llist.c
+++ b/lib/llist.c
@@ -41,7 +41,7 @@ bool llist_add_batch(struct llist_node *new_first, struct llist_node *new_last,
struct llist_node *first;
do {
- new_last->next = first = ACCESS_ONCE(head->first);
+ new_last->next = first = READ_ONCE(head->first);
} while (cmpxchg(&head->first, first, new_first) != first);
return !first;
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 86c3385b9eb3..1746bae94d41 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -620,8 +620,8 @@ char *dentry_name(char *buf, char *end, const struct dentry *d, struct printf_sp
rcu_read_lock();
for (i = 0; i < depth; i++, d = p) {
- p = ACCESS_ONCE(d->d_parent);
- array[i] = ACCESS_ONCE(d->d_name.name);
+ p = READ_ONCE(d->d_parent);
+ array[i] = READ_ONCE(d->d_name.name);
if (p == d) {
if (i)
array[i] = "";