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-rw-r--r--kernel/cgroup/cpuset.c7
-rw-r--r--kernel/exit.c1
-rw-r--r--kernel/fork.c4
-rw-r--r--kernel/futex.c61
-rw-r--r--kernel/jump_label.c104
-rw-r--r--kernel/locking/lockdep.c1008
-rw-r--r--kernel/locking/lockdep_internals.h2
-rw-r--r--kernel/locking/lockdep_proc.c4
-rw-r--r--kernel/locking/lockdep_states.h1
-rw-r--r--kernel/locking/osq_lock.c13
-rw-r--r--kernel/locking/qspinlock_paravirt.h24
-rw-r--r--kernel/locking/rtmutex_common.h29
-rw-r--r--kernel/locking/rwsem-spinlock.c37
-rw-r--r--kernel/locking/rwsem-xadd.c33
-rw-r--r--kernel/panic.c12
-rw-r--r--kernel/sched/completion.c11
-rw-r--r--kernel/sched/core.c4
-rw-r--r--kernel/sched/sched.h2
-rw-r--r--kernel/sched/swait.c6
-rw-r--r--kernel/smp.c32
-rw-r--r--kernel/up.c2
-rw-r--r--kernel/workqueue.c53
22 files changed, 1176 insertions, 274 deletions
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index df403e97b073..2f4039bafebb 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -577,6 +577,13 @@ static void update_domain_attr_tree(struct sched_domain_attr *dattr,
rcu_read_unlock();
}
+/* Must be called with cpuset_mutex held. */
+static inline int nr_cpusets(void)
+{
+ /* jump label reference count + the top-level cpuset */
+ return static_key_count(&cpusets_enabled_key.key) + 1;
+}
+
/*
* generate_sched_domains()
*
diff --git a/kernel/exit.c b/kernel/exit.c
index f9ef3ecc78c1..a35d8a17e01f 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -918,6 +918,7 @@ void __noreturn do_exit(long code)
exit_rcu();
exit_tasks_rcu_finish();
+ lockdep_free_task(tsk);
do_task_dead();
}
EXPORT_SYMBOL_GPL(do_exit);
diff --git a/kernel/fork.c b/kernel/fork.c
index b7e9e57b71ea..dab73d18bc4d 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -484,6 +484,8 @@ void __init fork_init(void)
cpuhp_setup_state(CPUHP_BP_PREPARE_DYN, "fork:vm_stack_cache",
NULL, free_vm_stack_cache);
#endif
+
+ lockdep_init_task(&init_task);
}
int __weak arch_dup_task_struct(struct task_struct *dst,
@@ -1700,6 +1702,7 @@ static __latent_entropy struct task_struct *copy_process(
p->lockdep_depth = 0; /* no locks held yet */
p->curr_chain_key = 0;
p->lockdep_recursion = 0;
+ lockdep_init_task(p);
#endif
#ifdef CONFIG_DEBUG_MUTEXES
@@ -1958,6 +1961,7 @@ bad_fork_cleanup_audit:
bad_fork_cleanup_perf:
perf_event_free_task(p);
bad_fork_cleanup_policy:
+ lockdep_free_task(p);
#ifdef CONFIG_NUMA
mpol_put(p->mempolicy);
bad_fork_cleanup_threadgroup_lock:
diff --git a/kernel/futex.c b/kernel/futex.c
index f50b434756c1..3d38eaf05492 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -876,6 +876,8 @@ static struct task_struct *futex_find_get_task(pid_t pid)
return p;
}
+#ifdef CONFIG_FUTEX_PI
+
/*
* This task is holding PI mutexes at exit time => bad.
* Kernel cleans up PI-state, but userspace is likely hosed.
@@ -933,6 +935,8 @@ void exit_pi_state_list(struct task_struct *curr)
raw_spin_unlock_irq(&curr->pi_lock);
}
+#endif
+
/*
* We need to check the following states:
*
@@ -1547,6 +1551,45 @@ out:
return ret;
}
+static int futex_atomic_op_inuser(unsigned int encoded_op, u32 __user *uaddr)
+{
+ unsigned int op = (encoded_op & 0x70000000) >> 28;
+ unsigned int cmp = (encoded_op & 0x0f000000) >> 24;
+ int oparg = sign_extend32((encoded_op & 0x00fff000) >> 12, 12);
+ int cmparg = sign_extend32(encoded_op & 0x00000fff, 12);
+ int oldval, ret;
+
+ if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) {
+ if (oparg < 0 || oparg > 31)
+ return -EINVAL;
+ oparg = 1 << oparg;
+ }
+
+ if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
+ return -EFAULT;
+
+ ret = arch_futex_atomic_op_inuser(op, oparg, &oldval, uaddr);
+ if (ret)
+ return ret;
+
+ switch (cmp) {
+ case FUTEX_OP_CMP_EQ:
+ return oldval == cmparg;
+ case FUTEX_OP_CMP_NE:
+ return oldval != cmparg;
+ case FUTEX_OP_CMP_LT:
+ return oldval < cmparg;
+ case FUTEX_OP_CMP_GE:
+ return oldval >= cmparg;
+ case FUTEX_OP_CMP_LE:
+ return oldval <= cmparg;
+ case FUTEX_OP_CMP_GT:
+ return oldval > cmparg;
+ default:
+ return -ENOSYS;
+ }
+}
+
/*
* Wake up all waiters hashed on the physical page that is mapped
* to this virtual address:
@@ -1800,6 +1843,15 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags,
struct futex_q *this, *next;
DEFINE_WAKE_Q(wake_q);
+ /*
+ * When PI not supported: return -ENOSYS if requeue_pi is true,
+ * consequently the compiler knows requeue_pi is always false past
+ * this point which will optimize away all the conditional code
+ * further down.
+ */
+ if (!IS_ENABLED(CONFIG_FUTEX_PI) && requeue_pi)
+ return -ENOSYS;
+
if (requeue_pi) {
/*
* Requeue PI only works on two distinct uaddrs. This
@@ -2595,6 +2647,9 @@ static int futex_lock_pi(u32 __user *uaddr, unsigned int flags,
struct futex_q q = futex_q_init;
int res, ret;
+ if (!IS_ENABLED(CONFIG_FUTEX_PI))
+ return -ENOSYS;
+
if (refill_pi_state_cache())
return -ENOMEM;
@@ -2774,6 +2829,9 @@ static int futex_unlock_pi(u32 __user *uaddr, unsigned int flags)
struct futex_q *top_waiter;
int ret;
+ if (!IS_ENABLED(CONFIG_FUTEX_PI))
+ return -ENOSYS;
+
retry:
if (get_user(uval, uaddr))
return -EFAULT;
@@ -2984,6 +3042,9 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
struct futex_q q = futex_q_init;
int res, ret;
+ if (!IS_ENABLED(CONFIG_FUTEX_PI))
+ return -ENOSYS;
+
if (uaddr == uaddr2)
return -EINVAL;
diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index d11c506a6ac3..0bf2e8f5244a 100644
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -79,29 +79,7 @@ int static_key_count(struct static_key *key)
}
EXPORT_SYMBOL_GPL(static_key_count);
-void static_key_enable(struct static_key *key)
-{
- int count = static_key_count(key);
-
- WARN_ON_ONCE(count < 0 || count > 1);
-
- if (!count)
- static_key_slow_inc(key);
-}
-EXPORT_SYMBOL_GPL(static_key_enable);
-
-void static_key_disable(struct static_key *key)
-{
- int count = static_key_count(key);
-
- WARN_ON_ONCE(count < 0 || count > 1);
-
- if (count)
- static_key_slow_dec(key);
-}
-EXPORT_SYMBOL_GPL(static_key_disable);
-
-void static_key_slow_inc(struct static_key *key)
+static void static_key_slow_inc_cpuslocked(struct static_key *key)
{
int v, v1;
@@ -125,24 +103,87 @@ void static_key_slow_inc(struct static_key *key)
return;
}
- cpus_read_lock();
jump_label_lock();
if (atomic_read(&key->enabled) == 0) {
atomic_set(&key->enabled, -1);
jump_label_update(key);
- atomic_set(&key->enabled, 1);
+ /*
+ * Ensure that if the above cmpxchg loop observes our positive
+ * value, it must also observe all the text changes.
+ */
+ atomic_set_release(&key->enabled, 1);
} else {
atomic_inc(&key->enabled);
}
jump_label_unlock();
+}
+
+void static_key_slow_inc(struct static_key *key)
+{
+ cpus_read_lock();
+ static_key_slow_inc_cpuslocked(key);
cpus_read_unlock();
}
EXPORT_SYMBOL_GPL(static_key_slow_inc);
-static void __static_key_slow_dec(struct static_key *key,
- unsigned long rate_limit, struct delayed_work *work)
+void static_key_enable_cpuslocked(struct static_key *key)
+{
+ STATIC_KEY_CHECK_USE();
+
+ if (atomic_read(&key->enabled) > 0) {
+ WARN_ON_ONCE(atomic_read(&key->enabled) != 1);
+ return;
+ }
+
+ jump_label_lock();
+ if (atomic_read(&key->enabled) == 0) {
+ atomic_set(&key->enabled, -1);
+ jump_label_update(key);
+ /*
+ * See static_key_slow_inc().
+ */
+ atomic_set_release(&key->enabled, 1);
+ }
+ jump_label_unlock();
+}
+EXPORT_SYMBOL_GPL(static_key_enable_cpuslocked);
+
+void static_key_enable(struct static_key *key)
+{
+ cpus_read_lock();
+ static_key_enable_cpuslocked(key);
+ cpus_read_unlock();
+}
+EXPORT_SYMBOL_GPL(static_key_enable);
+
+void static_key_disable_cpuslocked(struct static_key *key)
+{
+ STATIC_KEY_CHECK_USE();
+
+ if (atomic_read(&key->enabled) != 1) {
+ WARN_ON_ONCE(atomic_read(&key->enabled) != 0);
+ return;
+ }
+
+ jump_label_lock();
+ if (atomic_cmpxchg(&key->enabled, 1, 0))
+ jump_label_update(key);
+ jump_label_unlock();
+}
+EXPORT_SYMBOL_GPL(static_key_disable_cpuslocked);
+
+void static_key_disable(struct static_key *key)
{
cpus_read_lock();
+ static_key_disable_cpuslocked(key);
+ cpus_read_unlock();
+}
+EXPORT_SYMBOL_GPL(static_key_disable);
+
+static void static_key_slow_dec_cpuslocked(struct static_key *key,
+ unsigned long rate_limit,
+ struct delayed_work *work)
+{
/*
* The negative count check is valid even when a negative
* key->enabled is in use by static_key_slow_inc(); a
@@ -153,7 +194,6 @@ static void __static_key_slow_dec(struct static_key *key,
if (!atomic_dec_and_mutex_lock(&key->enabled, &jump_label_mutex)) {
WARN(atomic_read(&key->enabled) < 0,
"jump label: negative count!\n");
- cpus_read_unlock();
return;
}
@@ -164,6 +204,14 @@ static void __static_key_slow_dec(struct static_key *key,
jump_label_update(key);
}
jump_label_unlock();
+}
+
+static void __static_key_slow_dec(struct static_key *key,
+ unsigned long rate_limit,
+ struct delayed_work *work)
+{
+ cpus_read_lock();
+ static_key_slow_dec_cpuslocked(key, rate_limit, work);
cpus_read_unlock();
}
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 7d2499bec5fe..44c8d0d17170 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -58,6 +58,10 @@
#define CREATE_TRACE_POINTS
#include <trace/events/lock.h>
+#ifdef CONFIG_LOCKDEP_CROSSRELEASE
+#include <linux/slab.h>
+#endif
+
#ifdef CONFIG_PROVE_LOCKING
int prove_locking = 1;
module_param(prove_locking, int, 0644);
@@ -344,14 +348,12 @@ EXPORT_SYMBOL(lockdep_on);
#if VERBOSE
# define HARDIRQ_VERBOSE 1
# define SOFTIRQ_VERBOSE 1
-# define RECLAIM_VERBOSE 1
#else
# define HARDIRQ_VERBOSE 0
# define SOFTIRQ_VERBOSE 0
-# define RECLAIM_VERBOSE 0
#endif
-#if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE || RECLAIM_VERBOSE
+#if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE
/*
* Quick filtering for interesting events:
*/
@@ -726,6 +728,18 @@ look_up_lock_class(struct lockdep_map *lock, unsigned int subclass)
return is_static || static_obj(lock->key) ? NULL : ERR_PTR(-EINVAL);
}
+#ifdef CONFIG_LOCKDEP_CROSSRELEASE
+static void cross_init(struct lockdep_map *lock, int cross);
+static int cross_lock(struct lockdep_map *lock);
+static int lock_acquire_crosslock(struct held_lock *hlock);
+static int lock_release_crosslock(struct lockdep_map *lock);
+#else
+static inline void cross_init(struct lockdep_map *lock, int cross) {}
+static inline int cross_lock(struct lockdep_map *lock) { return 0; }
+static inline int lock_acquire_crosslock(struct held_lock *hlock) { return 2; }
+static inline int lock_release_crosslock(struct lockdep_map *lock) { return 2; }
+#endif
+
/*
* Register a lock's class in the hash-table, if the class is not present
* yet. Otherwise we look it up. We cache the result in the lock object
@@ -1125,22 +1139,41 @@ print_circular_lock_scenario(struct held_lock *src,
printk(KERN_CONT "\n\n");
}
- printk(" Possible unsafe locking scenario:\n\n");
- printk(" CPU0 CPU1\n");
- printk(" ---- ----\n");
- printk(" lock(");
- __print_lock_name(target);
- printk(KERN_CONT ");\n");
- printk(" lock(");
- __print_lock_name(parent);
- printk(KERN_CONT ");\n");
- printk(" lock(");
- __print_lock_name(target);
- printk(KERN_CONT ");\n");
- printk(" lock(");
- __print_lock_name(source);
- printk(KERN_CONT ");\n");
- printk("\n *** DEADLOCK ***\n\n");
+ if (cross_lock(tgt->instance)) {
+ printk(" Possible unsafe locking scenario by crosslock:\n\n");
+ printk(" CPU0 CPU1\n");
+ printk(" ---- ----\n");
+ printk(" lock(");
+ __print_lock_name(parent);
+ printk(KERN_CONT ");\n");
+ printk(" lock(");
+ __print_lock_name(target);
+ printk(KERN_CONT ");\n");
+ printk(" lock(");
+ __print_lock_name(source);
+ printk(KERN_CONT ");\n");
+ printk(" unlock(");
+ __print_lock_name(target);
+ printk(KERN_CONT ");\n");
+ printk("\n *** DEADLOCK ***\n\n");
+ } else {
+ printk(" Possible unsafe locking scenario:\n\n");
+ printk(" CPU0 CPU1\n");
+ printk(" ---- ----\n");
+ printk(" lock(");
+ __print_lock_name(target);
+ printk(KERN_CONT ");\n");
+ printk(" lock(");
+ __print_lock_name(parent);
+ printk(KERN_CONT ");\n");
+ printk(" lock(");
+ __print_lock_name(target);
+ printk(KERN_CONT ");\n");
+ printk(" lock(");
+ __print_lock_name(source);
+ printk(KERN_CONT ");\n");
+ printk("\n *** DEADLOCK ***\n\n");
+ }
}
/*
@@ -1165,7 +1198,12 @@ print_circular_bug_header(struct lock_list *entry, unsigned int depth,
pr_warn("%s/%d is trying to acquire lock:\n",
curr->comm, task_pid_nr(curr));
print_lock(check_src);
- pr_warn("\nbut task is already holding lock:\n");
+
+ if (cross_lock(check_tgt->instance))
+ pr_warn("\nbut now in release context of a crosslock acquired at the following:\n");
+ else
+ pr_warn("\nbut task is already holding lock:\n");
+
print_lock(check_tgt);
pr_warn("\nwhich lock already depends on the new lock.\n\n");
pr_warn("\nthe existing dependency chain (in reverse order) is:\n");
@@ -1183,7 +1221,8 @@ static inline int class_equal(struct lock_list *entry, void *data)
static noinline int print_circular_bug(struct lock_list *this,
struct lock_list *target,
struct held_lock *check_src,
- struct held_lock *check_tgt)
+ struct held_lock *check_tgt,
+ struct stack_trace *trace)
{
struct task_struct *curr = current;
struct lock_list *parent;
@@ -1193,7 +1232,9 @@ static noinline int print_circular_bug(struct lock_list *this,
if (!debug_locks_off_graph_unlock() || debug_locks_silent)
return 0;
- if (!save_trace(&this->trace))
+ if (cross_lock(check_tgt->instance))
+ this->trace = *trace;
+ else if (!save_trace(&this->trace))
return 0;
depth = get_lock_depth(target);
@@ -1309,6 +1350,19 @@ check_noncircular(struct lock_list *root, struct lock_class *target,
return result;
}
+static noinline int
+check_redundant(struct lock_list *root, struct lock_class *target,
+ struct lock_list **target_entry)
+{
+ int result;
+
+ debug_atomic_inc(nr_redundant_checks);
+
+ result = __bfs_forwards(root, target, class_equal, target_entry);
+
+ return result;
+}
+
#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
/*
* Forwards and backwards subgraph searching, for the purposes of
@@ -1784,6 +1838,9 @@ check_deadlock(struct task_struct *curr, struct held_lock *next,
if (nest)
return 2;
+ if (cross_lock(prev->instance))
+ continue;
+
return print_deadlock_bug(curr, prev, next);
}
return 1;
@@ -1813,20 +1870,13 @@ check_deadlock(struct task_struct *curr, struct held_lock *next,
*/
static int
check_prev_add(struct task_struct *curr, struct held_lock *prev,
- struct held_lock *next, int distance, int *stack_saved)
+ struct held_lock *next, int distance, struct stack_trace *trace,
+ int (*save)(struct stack_trace *trace))
{
struct lock_list *entry;
int ret;
struct lock_list this;
struct lock_list *uninitialized_var(target_entry);
- /*
- * Static variable, serialized by the graph_lock().
- *
- * We use this static variable to save the stack trace in case
- * we call into this function multiple times due to encountering
- * trylocks in the held lock stack.
- */
- static struct stack_trace trace;
/*
* Prove that the new <prev> -> <next> dependency would not
@@ -1841,7 +1891,7 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev,
this.parent = NULL;
ret = check_noncircular(&this, hlock_class(prev), &target_entry);
if (unlikely(!ret))
- return print_circular_bug(&this, target_entry, next, prev);
+ return print_circular_bug(&this, target_entry, next, prev, trace);
else if (unlikely(ret < 0))
return print_bfs_bug(ret);
@@ -1870,15 +1920,26 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev,
if (entry->class == hlock_class(next)) {
if (distance == 1)
entry->distance = 1;
- return 2;
+ return 1;
}
}
- if (!*stack_saved) {
- if (!save_trace(&trace))
- return 0;
- *stack_saved = 1;
+ /*
+ * Is the <prev> -> <next> link redundant?
+ */
+ this.class = hlock_class(prev);
+ this.parent = NULL;
+ ret = check_redundant(&this, hlock_class(next), &target_entry);
+ if (!ret) {
+ debug_atomic_inc(nr_redundant);
+ return 2;
}
+ if (ret < 0)
+ return print_bfs_bug(ret);
+
+
+ if (save && !save(trace))
+ return 0;
/*
* Ok, all validations passed, add the new lock
@@ -1886,14 +1947,14 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev,
*/
ret = add_lock_to_list(hlock_class(next),
&hlock_class(prev)->locks_after,
- next->acquire_ip, distance, &trace);
+ next->acquire_ip, distance, trace);
if (!ret)
return 0;
ret = add_lock_to_list(hlock_class(prev),
&hlock_class(next)->locks_before,
- next->acquire_ip, distance, &trace);
+ next->acquire_ip, distance, trace);
if (!ret)
return 0;
@@ -1901,8 +1962,6 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev,
* Debugging printouts:
*/
if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) {
- /* We drop graph lock, so another thread can overwrite trace. */
- *stack_saved = 0;
graph_unlock();
printk("\n new dependency: ");
print_lock_name(hlock_class(prev));
@@ -1910,9 +1969,10 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev,
print_lock_name(hlock_class(next));
printk(KERN_CONT "\n");
dump_stack();
- return graph_lock();
+ if (!graph_lock())
+ return 0;
}
- return 1;
+ return 2;
}
/*
@@ -1925,8 +1985,9 @@ static int
check_prevs_add(struct task_struct *curr, struct held_lock *next)
{
int depth = curr->lockdep_depth;
- int stack_saved = 0;
struct held_lock *hlock;
+ struct stack_trace trace;
+ int (*save)(struct stack_trace *trace) = save_trace;
/*
* Debugging checks.
@@ -1947,21 +2008,36 @@ check_prevs_add(struct task_struct *curr, struct held_lock *next)
int distance = curr->lockdep_depth - depth + 1;
hlock = curr->held_locks + depth - 1;
/*
- * Only non-recursive-read entries get new dependencies
- * added:
+ * Only non-crosslock entries get new dependencies added.
+ * Crosslock entries will be added by commit later:
*/
- if (hlock->read != 2 && hlock->check) {
- if (!check_prev_add(curr, hlock, next,
- distance, &stack_saved))
- return 0;
+ if (!cross_lock(hlock->instance)) {
/*
- * Stop after the first non-trylock entry,
- * as non-trylock entries have added their
- * own direct dependencies already, so this
- * lock is connected to them indirectly:
+ * Only non-recursive-read entries get new dependencies
+ * added:
*/
- if (!hlock->trylock)
- break;
+ if (hlock->read != 2 && hlock->check) {
+ int ret = check_prev_add(curr, hlock, next,
+ distance, &trace, save);
+ if (!ret)
+ return 0;
+
+ /*
+ * Stop saving stack_trace if save_trace() was
+ * called at least once:
+ */
+ if (save && ret == 2)
+ save = NULL;
+
+ /*
+ * Stop after the first non-trylock entry,
+ * as non-trylock entries have added their
+ * own direct dependencies already, so this
+ * lock is connected to them indirectly:
+ */
+ if (!hlock->trylock)
+ break;
+ }
}
depth--;
/*
@@ -2126,19 +2202,26 @@ static int check_no_collision(struct task_struct *curr,
}
/*
- * Look up a dependency chain. If the key is not present yet then
- * add it and return 1 - in this case the new dependency chain is
- * validated. If the key is already hashed, return 0.
- * (On return with 1 graph_lock is held.)
+ * This is for building a chain between just two different classes,
+ * instead of adding a new hlock upon current, which is done by
+ * add_chain_cache().
+ *
+ * This can be called in any context with two classes, while
+ * add_chain_cache() must be done within the lock owener's context
+ * since it uses hlock which might be racy in another context.
*/
-static inline int lookup_chain_cache(struct task_struct *curr,
- struct held_lock *hlock,
- u64 chain_key)
+static inline int add_chain_cache_classes(unsigned int prev,
+ unsigned int next,
+ unsigned int irq_context,
+ u64 chain_key)
{
- struct lock_class *class = hlock_class(hlock);
struct hlist_head *hash_head = chainhashentry(chain_key);
struct lock_chain *chain;
- int i, j;
+
+ /*
+ * Allocate a new chain entry from the static array, and add
+ * it to the hash:
+ */
/*
* We might need to take the graph lock, ensure we've got IRQs
@@ -2147,43 +2230,76 @@ static inline int lookup_chain_cache(struct task_struct *curr,
*/
if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
return 0;
+
+ if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) {
+ if (!debug_locks_off_graph_unlock())
+ return 0;
+
+ print_lockdep_off("BUG: MAX_LOCKDEP_CHAINS too low!");
+ dump_stack();
+ return 0;
+ }
+
+ chain = lock_chains + nr_lock_chains++;
+ chain->chain_key = chain_key;
+ chain->irq_context = irq_context;
+ chain->depth = 2;
+ if (likely(nr_chain_hlocks + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) {
+ chain->base = nr_chain_hlocks;
+ nr_chain_hlocks += chain->depth;
+ chain_hlocks[chain->base] = prev - 1;
+ chain_hlocks[chain->base + 1] = next -1;
+ }
+#ifdef CONFIG_DEBUG_LOCKDEP
/*
- * We can walk it lock-free, because entries only get added
- * to the hash:
+ * Important for check_no_collision().
*/
- hlist_for_each_entry_rcu(chain, hash_head, entry) {
- if (chain->chain_key == chain_key) {
-cache_hit:
- debug_atomic_inc(chain_lookup_hits);
- if (!check_no_collision(curr, hlock, chain))
- return 0;
-
- if (very_verbose(class))
- printk("\nhash chain already cached, key: "
- "%016Lx tail class: [%p] %s\n",
- (unsigned long long)chain_key,
- class->key, class->name);
+ else {
+ if (!debug_locks_off_graph_unlock())
return 0;
- }
+
+ print_lockdep_off("BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!");
+ dump_stack();
+ return 0;
}
- if (very_verbose(class))
- printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n",
- (unsigned long long)chain_key, class->key, class->name);
+#endif
+
+ hlist_add_head_rcu(&chain->entry, hash_head);
+ debug_atomic_inc(chain_lookup_misses);
+ inc_chains();
+
+ return 1;
+}
+
+/*
+ * Adds a dependency chain into chain hashtable. And must be called with
+ * graph_lock held.
+ *
+ * Return 0 if fail, and graph_lock is released.
+ * Return 1 if succeed, with graph_lock held.
+ */
+static inline int add_chain_cache(struct task_struct *curr,
+ struct held_lock *hlock,
+ u64 chain_key)
+{
+ struct lock_class *class = hlock_class(hlock);
+ struct hlist_head *hash_head = chainhashentry(chain_key);
+ struct lock_chain *chain;
+ int i, j;
+
/*
* Allocate a new chain entry from the static array, and add
* it to the hash:
*/
- if (!graph_lock())
- return 0;
+
/*
- * We have to walk the chain again locked - to avoid duplicates:
+ * We might need to take the graph lock, ensure we've got IRQs
+ * disabled to make this an IRQ-safe lock.. for recursion reasons
+ * lockdep won't complain about its own locking errors.
*/
- hlist_for_each_entry(chain, hash_head, entry) {
- if (chain->chain_key == chain_key) {
- graph_unlock();
- goto cache_hit;
- }
- }
+ if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+ return 0;
+
if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) {
if (!debug_locks_off_graph_unlock())
return 0;
@@ -2235,6 +2351,78 @@ cache_hit:
return 1;
}
+/*
+ * Look up a dependency chain.
+ */
+static inline struct lock_chain *lookup_chain_cache(u64 chain_key)
+{
+ struct hlist_head *hash_head = chainhashentry(chain_key);
+ struct lock_chain *chain;
+
+ /*
+ * We can walk it lock-free, because entries only get added
+ * to the hash:
+ */
+ hlist_for_each_entry_rcu(chain, hash_head, entry) {
+ if (chain->chain_key == chain_key) {
+ debug_atomic_inc(chain_lookup_hits);
+ return chain;
+ }
+ }
+ return NULL;
+}
+
+/*
+ * If the key is not present yet in dependency chain cache then
+ * add it and return 1 - in this case the new dependency chain is
+ * validated. If the key is already hashed, return 0.
+ * (On return with 1 graph_lock is held.)
+ */
+static inline int lookup_chain_cache_add(struct task_struct *curr,
+ struct held_lock *hlock,
+ u64 chain_key)
+{
+ struct lock_class *class = hlock_class(hlock);
+ struct lock_chain *chain = lookup_chain_cache(chain_key);
+
+ if (chain) {
+cache_hit:
+ if (!check_no_collision(curr, hlock, chain))
+ return 0;
+
+ if (very_verbose(class)) {
+ printk("\nhash chain already cached, key: "
+ "%016Lx tail class: [%p] %s\n",
+ (unsigned long long)chain_key,
+ class->key, class->name);
+ }
+
+ return 0;
+ }
+
+ if (very_verbose(class)) {
+ printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n",
+ (unsigned long long)chain_key, class->key, class->name);
+ }
+
+ if (!graph_lock())
+ return 0;
+
+ /*
+ * We have to walk the chain again locked - to avoid duplicates:
+ */
+ chain = lookup_chain_cache(chain_key);
+ if (chain) {
+ graph_unlock();
+ goto cache_hit;
+ }
+
+ if (!add_chain_cache(curr, hlock, chain_key))
+ return 0;
+
+ return 1;
+}
+
static int validate_chain(struct task_struct *curr, struct lockdep_map *lock,
struct held_lock *hlock, int chain_head, u64 chain_key)
{
@@ -2245,11 +2433,11 @@ static int validate_chain(struct task_struct *curr, struct lockdep_map *lock,
*
* We look up the chain_key and do the O(N^2) check and update of
* the dependencies only if this is a new dependency chain.
- * (If lookup_chain_cache() returns with 1 it acquires
+ * (If lookup_chain_cache_add() return with 1 it acquires
* graph_lock for us)
*/
if (!hlock->trylock && hlock->check &&
- lookup_chain_cache(curr, hlock, chain_key)) {
+ lookup_chain_cache_add(curr, hlock, chain_key)) {
/*
* Check whether last held lock:
*
@@ -2277,14 +2465,17 @@ static int validate_chain(struct task_struct *curr, struct lockdep_map *lock,
* Add dependency only if this lock is not the head
* of the chain, and if it's not a secondary read-lock:
*/
- if (!chain_head && ret != 2)
+ if (!chain_head && ret != 2) {
if (!check_prevs_add(curr, hlock))
return 0;
+ }
+
graph_unlock();
- } else
- /* after lookup_chain_cache(): */
+ } else {
+ /* after lookup_chain_cache_add(): */
if (unlikely(!debug_locks))
return 0;
+ }
return 1;
}
@@ -2567,14 +2758,6 @@ static int SOFTIRQ_verbose(struct lock_class *class)
return 0;
}
-static int RECLAIM_FS_verbose(struct lock_class *class)
-{
-#if RECLAIM_VERBOSE
- return class_filter(class);
-#endif
- return 0;
-}
-
#define STRICT_READ_CHECKS 1
static int (*state_verbose_f[])(struct lock_class *class) = {
@@ -2870,57 +3053,6 @@ void trace_softirqs_off(unsigned long ip)
debug_atomic_inc(redundant_softirqs_off);
}
-static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags)
-{
- struct task_struct *curr = current;
-
- if (unlikely(!debug_locks))
- return;
-
- gfp_mask = current_gfp_context(gfp_mask);
-
- /* no reclaim without waiting on it */
- if (!(gfp_mask & __GFP_DIRECT_RECLAIM))
- return;
-
- /* this guy won't enter reclaim */
- if ((curr->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC))
- return;
-
- /* We're only interested __GFP_FS allocations for now */
- if (!(gfp_mask & __GFP_FS) || (curr->flags & PF_MEMALLOC_NOFS))
- return;
-
- /*
- * Oi! Can't be having __GFP_FS allocations with IRQs disabled.
- */
- if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags)))
- return;
-
- /* Disable lockdep if explicitly requested */
- if (gfp_mask & __GFP_NOLOCKDEP)
- return;
-
- mark_held_locks(curr, RECLAIM_FS);
-}
-
-static void check_flags(unsigned long flags);
-
-void lockdep_trace_alloc(gfp_t gfp_mask)
-{
- unsigned long flags;
-
- if (unlikely(current->lockdep_recursion))
- return;
-
- raw_local_irq_save(flags);
- check_flags(flags);
- current->lockdep_recursion = 1;
- __lockdep_trace_alloc(gfp_mask, flags);
- current->lockdep_recursion = 0;
- raw_local_irq_restore(flags);
-}
-
static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock)
{
/*
@@ -2966,22 +3098,6 @@ static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock)
}
}
- /*
- * We reuse the irq context infrastructure more broadly as a general
- * context checking code. This tests GFP_FS recursion (a lock taken
- * during reclaim for a GFP_FS allocation is held over a GFP_FS
- * allocation).
- */
- if (!hlock->trylock && (curr->lockdep_reclaim_gfp & __GFP_FS)) {
- if (hlock->read) {
- if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS_READ))
- return 0;
- } else {
- if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS))
- return 0;
- }
- }
-
return 1;
}
@@ -3040,10 +3156,6 @@ static inline int separate_irq_context(struct task_struct *curr,
return 0;
}
-void lockdep_trace_alloc(gfp_t gfp_mask)
-{
-}
-
#endif /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */
/*
@@ -3116,7 +3228,7 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this,
/*
* Initialize a lock instance's lock-class mapping info:
*/
-void lockdep_init_map(struct lockdep_map *lock, const char *name,
+static void __lockdep_init_map(struct lockdep_map *lock, const char *name,
struct lock_class_key *key, int subclass)
{
int i;
@@ -3174,8 +3286,25 @@ void lockdep_init_map(struct lockdep_map *lock, const char *name,
raw_local_irq_restore(flags);
}
}
+
+void lockdep_init_map(struct lockdep_map *lock, const char *name,
+ struct lock_class_key *key, int subclass)
+{
+ cross_init(lock, 0);
+ __lockdep_init_map(lock, name, key, subclass);
+}
EXPORT_SYMBOL_GPL(lockdep_init_map);
+#ifdef CONFIG_LOCKDEP_CROSSRELEASE
+void lockdep_init_map_crosslock(struct lockdep_map *lock, const char *name,
+ struct lock_class_key *key, int subclass)
+{
+ cross_init(lock, 1);
+ __lockdep_init_map(lock, name, key, subclass);
+}
+EXPORT_SYMBOL_GPL(lockdep_init_map_crosslock);
+#endif
+
struct lock_class_key __lockdep_no_validate__;
EXPORT_SYMBOL_GPL(__lockdep_no_validate__);
@@ -3231,6 +3360,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
int chain_head = 0;
int class_idx;
u64 chain_key;
+ int ret;
if (unlikely(!debug_locks))
return 0;
@@ -3279,7 +3409,8 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
class_idx = class - lock_classes + 1;
- if (depth) {
+ /* TODO: nest_lock is not implemented for crosslock yet. */
+ if (depth && !cross_lock(lock)) {
hlock = curr->held_locks + depth - 1;
if (hlock->class_idx == class_idx && nest_lock) {
if (hlock->references) {
@@ -3367,6 +3498,14 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
if (!validate_chain(curr, lock, hlock, chain_head, chain_key))
return 0;
+ ret = lock_acquire_crosslock(hlock);
+ /*
+ * 2 means normal acquire operations are needed. Otherwise, it's
+ * ok just to return with '0:fail, 1:success'.
+ */
+ if (ret != 2)
+ return ret;
+
curr->curr_chain_key = chain_key;
curr->lockdep_depth++;
check_chain_key(curr);
@@ -3604,11 +3743,19 @@ __lock_release(struct lockdep_map *lock, int nested, unsigned long ip)
struct task_struct *curr = current;
struct held_lock *hlock;
unsigned int depth;
- int i;
+ int ret, i;
if (unlikely(!debug_locks))
return 0;
+ ret = lock_release_crosslock(lock);
+ /*
+ * 2 means normal release operations are needed. Otherwise, it's
+ * ok just to return with '0:fail, 1:success'.
+ */
+ if (ret != 2)
+ return ret;
+
depth = curr->lockdep_depth;
/*
* So we're all set to release this lock.. wait what lock? We don't
@@ -3952,18 +4099,6 @@ void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie cookie)
}
EXPORT_SYMBOL_GPL(lock_unpin_lock);
-void lockdep_set_current_reclaim_state(gfp_t gfp_mask)
-{
- current->lockdep_reclaim_gfp = current_gfp_context(gfp_mask);
-}
-EXPORT_SYMBOL_GPL(lockdep_set_current_reclaim_state);
-
-void lockdep_clear_current_reclaim_state(void)
-{
- current->lockdep_reclaim_gfp = 0;
-}
-EXPORT_SYMBOL_GPL(lockdep_clear_current_reclaim_state);
-
#ifdef CONFIG_LOCK_STAT
static int
print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock,
@@ -4484,6 +4619,12 @@ asmlinkage __visible void lockdep_sys_exit(void)
curr->comm, curr->pid);
lockdep_print_held_locks(curr);
}
+
+ /*
+ * The lock history for each syscall should be independent. So wipe the
+ * slate clean on return to userspace.
+ */
+ lockdep_invariant_state(false);
}
void lockdep_rcu_suspicious(const char *file, const int line, const char *s)
@@ -4532,3 +4673,488 @@ void lockdep_rcu_suspicious(const char *file, const int line, const char *s)
dump_stack();
}
EXPORT_SYMBOL_GPL(lockdep_rcu_suspicious);
+
+#ifdef CONFIG_LOCKDEP_CROSSRELEASE
+
+/*
+ * Crossrelease works by recording a lock history for each thread and
+ * connecting those historic locks that were taken after the
+ * wait_for_completion() in the complete() context.
+ *
+ * Task-A Task-B
+ *
+ * mutex_lock(&A);
+ * mutex_unlock(&A);
+ *
+ * wait_for_completion(&C);
+ * lock_acquire_crosslock();
+ * atomic_inc_return(&cross_gen_id);
+ * |
+ * | mutex_lock(&B);
+ * | mutex_unlock(&B);
+ * |
+ * | complete(&C);
+ * `-- lock_commit_crosslock();
+ *
+ * Which will then add a dependency between B and C.
+ */
+
+#define xhlock(i) (current->xhlocks[(i) % MAX_XHLOCKS_NR])
+
+/*
+ * Whenever a crosslock is held, cross_gen_id will be increased.
+ */
+static atomic_t cross_gen_id; /* Can be wrapped */
+
+/*
+ * Make an entry of the ring buffer invalid.
+ */
+static inline void invalidate_xhlock(struct hist_lock *xhlock)
+{
+ /*
+ * Normally, xhlock->hlock.instance must be !NULL.
+ */
+ xhlock->hlock.instance = NULL;
+}
+
+/*
+ * Lock history stacks; we have 2 nested lock history stacks:
+ *
+ * HARD(IRQ)
+ * SOFT(IRQ)
+ *
+ * The thing is that once we complete a HARD/SOFT IRQ the future task locks
+ * should not depend on any of the locks observed while running the IRQ. So
+ * what we do is rewind the history buffer and erase all our knowledge of that
+ * temporal event.
+ */
+
+void crossrelease_hist_start(enum xhlock_context_t c)
+{
+ struct task_struct *cur = current;
+
+ if (!cur->xhlocks)
+ return;
+
+ cur->xhlock_idx_hist[c] = cur->xhlock_idx;
+ cur->hist_id_save[c] = cur->hist_id;
+}
+
+void crossrelease_hist_end(enum xhlock_context_t c)
+{
+ struct task_struct *cur = current;
+
+ if (cur->xhlocks) {
+ unsigned int idx = cur->xhlock_idx_hist[c];
+ struct hist_lock *h = &xhlock(idx);
+
+ cur->xhlock_idx = idx;
+
+ /* Check if the ring was overwritten. */
+ if (h->hist_id != cur->hist_id_save[c])
+ invalidate_xhlock(h);
+ }
+}
+
+/*
+ * lockdep_invariant_state() is used to annotate independence inside a task, to
+ * make one task look like multiple independent 'tasks'.
+ *
+ * Take for instance workqueues; each work is independent of the last. The
+ * completion of a future work does not depend on the completion of a past work
+ * (in general). Therefore we must not carry that (lock) dependency across
+ * works.
+ *
+ * This is true for many things; pretty much all kthreads fall into this
+ * pattern, where they have an invariant state and future completions do not
+ * depend on past completions. Its just that since they all have the 'same'
+ * form -- the kthread does the same over and over -- it doesn't typically
+ * matter.
+ *
+ * The same is true for system-calls, once a system call is completed (we've
+ * returned to userspace) the next system call does not depend on the lock
+ * history of the previous system call.
+ *
+ * They key property for independence, this invariant state, is that it must be
+ * a point where we hold no locks and have no history. Because if we were to
+ * hold locks, the restore at _end() would not necessarily recover it's history
+ * entry. Similarly, independence per-definition means it does not depend on
+ * prior state.
+ */
+void lockdep_invariant_state(bool force)
+{
+ /*
+ * We call this at an invariant point, no current state, no history.
+ * Verify the former, enforce the latter.
+ */
+ WARN_ON_ONCE(!force && current->lockdep_depth);
+ invalidate_xhlock(&xhlock(current->xhlock_idx));
+}
+
+static int cross_lock(struct lockdep_map *lock)
+{
+ return lock ? lock->cross : 0;
+}
+
+/*
+ * This is needed to decide the relationship between wrapable variables.
+ */
+static inline int before(unsigned int a, unsigned int b)
+{
+ return (int)(a - b) < 0;
+}
+
+static inline struct lock_class *xhlock_class(struct hist_lock *xhlock)
+{
+ return hlock_class(&xhlock->hlock);
+}
+
+static inline struct lock_class *xlock_class(struct cross_lock *xlock)
+{
+ return hlock_class(&xlock->hlock);
+}
+
+/*
+ * Should we check a dependency with previous one?
+ */
+static inline int depend_before(struct held_lock *hlock)
+{
+ return hlock->read != 2 && hlock->check && !hlock->trylock;
+}
+
+/*
+ * Should we check a dependency with next one?
+ */
+static inline int depend_after(struct held_lock *hlock)
+{
+ return hlock->read != 2 && hlock->check;
+}
+
+/*
+ * Check if the xhlock is valid, which would be false if,
+ *
+ * 1. Has not used after initializaion yet.
+ * 2. Got invalidated.
+ *
+ * Remind hist_lock is implemented as a ring buffer.
+ */
+static inline int xhlock_valid(struct hist_lock *xhlock)
+{
+ /*
+ * xhlock->hlock.instance must be !NULL.
+ */
+ return !!xhlock->hlock.instance;
+}
+
+/*
+ * Record a hist_lock entry.
+ *
+ * Irq disable is only required.
+ */
+static void add_xhlock(struct held_lock *hlock)
+{
+ unsigned int idx = ++current->xhlock_idx;
+ struct hist_lock *xhlock = &xhlock(idx);
+
+#ifdef CONFIG_DEBUG_LOCKDEP
+ /*
+ * This can be done locklessly because they are all task-local
+ * state, we must however ensure IRQs are disabled.
+ */
+ WARN_ON_ONCE(!irqs_disabled());
+#endif
+
+ /* Initialize hist_lock's members */
+ xhlock->hlock = *hlock;
+ xhlock->hist_id = ++current->hist_id;
+
+ xhlock->trace.nr_entries = 0;
+ xhlock->trace.max_entries = MAX_XHLOCK_TRACE_ENTRIES;
+ xhlock->trace.entries = xhlock->trace_entries;
+ xhlock->trace.skip = 3;
+ save_stack_trace(&xhlock->trace);
+}
+
+static inline int same_context_xhlock(struct hist_lock *xhlock)
+{
+ return xhlock->hlock.irq_context == task_irq_context(current);
+}
+
+/*
+ * This should be lockless as far as possible because this would be
+ * called very frequently.
+ */
+static void check_add_xhlock(struct held_lock *hlock)
+{
+ /*
+ * Record a hist_lock, only in case that acquisitions ahead
+ * could depend on the held_lock. For example, if the held_lock
+ * is trylock then acquisitions ahead never depends on that.
+ * In that case, we don't need to record it. Just return.
+ */
+ if (!current->xhlocks || !depend_before(hlock))
+ return;
+
+ add_xhlock(hlock);
+}
+
+/*
+ * For crosslock.
+ */
+static int add_xlock(struct held_lock *hlock)
+{
+ struct cross_lock *xlock;
+ unsigned int gen_id;
+
+ if (!graph_lock())
+ return 0;
+
+ xlock = &((struct lockdep_map_cross *)hlock->instance)->xlock;
+
+ /*
+ * When acquisitions for a crosslock are overlapped, we use
+ * nr_acquire to perform commit for them, based on cross_gen_id
+ * of the first acquisition, which allows to add additional
+ * dependencies.
+ *
+ * Moreover, when no acquisition of a crosslock is in progress,
+ * we should not perform commit because the lock might not exist
+ * any more, which might cause incorrect memory access. So we
+ * have to track the number of acquisitions of a crosslock.
+ *
+ * depend_after() is necessary to initialize only the first
+ * valid xlock so that the xlock can be used on its commit.
+ */
+ if (xlock->nr_acquire++ && depend_after(&xlock->hlock))
+ goto unlock;
+
+ gen_id = (unsigned int)atomic_inc_return(&cross_gen_id);
+ xlock->hlock = *hlock;
+ xlock->hlock.gen_id = gen_id;
+unlock:
+ graph_unlock();
+ return 1;
+}
+
+/*
+ * Called for both normal and crosslock acquires. Normal locks will be
+ * pushed on the hist_lock queue. Cross locks will record state and
+ * stop regular lock_acquire() to avoid being placed on the held_lock
+ * stack.
+ *
+ * Return: 0 - failure;
+ * 1 - crosslock, done;
+ * 2 - normal lock, continue to held_lock[] ops.
+ */
+static int lock_acquire_crosslock(struct held_lock *hlock)
+{
+ /*
+ * CONTEXT 1 CONTEXT 2
+ * --------- ---------
+ * lock A (cross)
+ * X = atomic_inc_return(&cross_gen_id)
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ * Y = atomic_read_acquire(&cross_gen_id)
+ * lock B
+ *
+ * atomic_read_acquire() is for ordering between A and B,
+ * IOW, A happens before B, when CONTEXT 2 see Y >= X.
+ *
+ * Pairs with atomic_inc_return() in add_xlock().
+ */
+ hlock->gen_id = (unsigned int)atomic_read_acquire(&cross_gen_id);
+
+ if (cross_lock(hlock->instance))
+ return add_xlock(hlock);
+
+ check_add_xhlock(hlock);
+ return 2;
+}
+
+static int copy_trace(struct stack_trace *trace)
+{
+ unsigned long *buf = stack_trace + nr_stack_trace_entries;
+ unsigned int max_nr = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries;
+ unsigned int nr = min(max_nr, trace->nr_entries);
+
+ trace->nr_entries = nr;
+ memcpy(buf, trace->entries, nr * sizeof(trace->entries[0]));
+ trace->entries = buf;
+ nr_stack_trace_entries += nr;
+
+ if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) {
+ if (!debug_locks_off_graph_unlock())
+ return 0;
+
+ print_lockdep_off("BUG: MAX_STACK_TRACE_ENTRIES too low!");
+ dump_stack();
+
+ return 0;
+ }
+
+ return 1;
+}
+
+static int commit_xhlock(struct cross_lock *xlock, struct hist_lock *xhlock)
+{
+ unsigned int xid, pid;
+ u64 chain_key;
+
+ xid = xlock_class(xlock) - lock_classes;
+ chain_key = iterate_chain_key((u64)0, xid);
+ pid = xhlock_class(xhlock) - lock_classes;
+ chain_key = iterate_chain_key(chain_key, pid);
+
+ if (lookup_chain_cache(chain_key))
+ return 1;
+
+ if (!add_chain_cache_classes(xid, pid, xhlock->hlock.irq_context,
+ chain_key))
+ return 0;
+
+ if (!check_prev_add(current, &xlock->hlock, &xhlock->hlock, 1,
+ &xhlock->trace, copy_trace))
+ return 0;
+
+ return 1;
+}
+
+static void commit_xhlocks(struct cross_lock *xlock)
+{
+ unsigned int cur = current->xhlock_idx;
+ unsigned int prev_hist_id = xhlock(cur).hist_id;
+ unsigned int i;
+
+ if (!graph_lock())
+ return;
+
+ if (xlock->nr_acquire) {
+ for (i = 0; i < MAX_XHLOCKS_NR; i++) {
+ struct hist_lock *xhlock = &xhlock(cur - i);
+
+ if (!xhlock_valid(xhlock))
+ break;
+
+ if (before(xhlock->hlock.gen_id, xlock->hlock.gen_id))
+ break;
+
+ if (!same_context_xhlock(xhlock))
+ break;
+
+ /*
+ * Filter out the cases where the ring buffer was
+ * overwritten and the current entry has a bigger
+ * hist_id than the previous one, which is impossible
+ * otherwise:
+ */
+ if (unlikely(before(prev_hist_id, xhlock->hist_id)))
+ break;
+
+ prev_hist_id = xhlock->hist_id;
+
+ /*
+ * commit_xhlock() returns 0 with graph_lock already
+ * released if fail.
+ */
+ if (!commit_xhlock(xlock, xhlock))
+ return;
+ }
+ }
+
+ graph_unlock();
+}
+
+void lock_commit_crosslock(struct lockdep_map *lock)
+{
+ struct cross_lock *xlock;
+ unsigned long flags;
+
+ if (unlikely(!debug_locks || current->lockdep_recursion))
+ return;
+
+ if (!current->xhlocks)
+ return;
+
+ /*
+ * Do commit hist_locks with the cross_lock, only in case that
+ * the cross_lock could depend on acquisitions after that.
+ *
+ * For example, if the cross_lock does not have the 'check' flag
+ * then we don't need to check dependencies and commit for that.
+ * Just skip it. In that case, of course, the cross_lock does
+ * not depend on acquisitions ahead, either.
+ *
+ * WARNING: Don't do that in add_xlock() in advance. When an
+ * acquisition context is different from the commit context,
+ * invalid(skipped) cross_lock might be accessed.
+ */
+ if (!depend_after(&((struct lockdep_map_cross *)lock)->xlock.hlock))
+ return;
+
+ raw_local_irq_save(flags);
+ check_flags(flags);
+ current->lockdep_recursion = 1;
+ xlock = &((struct lockdep_map_cross *)lock)->xlock;
+ commit_xhlocks(xlock);
+ current->lockdep_recursion = 0;
+ raw_local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(lock_commit_crosslock);
+
+/*
+ * Return: 0 - failure;
+ * 1 - crosslock, done;
+ * 2 - normal lock, continue to held_lock[] ops.
+ */
+static int lock_release_crosslock(struct lockdep_map *lock)
+{
+ if (cross_lock(lock)) {
+ if (!graph_lock())
+ return 0;
+ ((struct lockdep_map_cross *)lock)->xlock.nr_acquire--;
+ graph_unlock();
+ return 1;
+ }
+ return 2;
+}
+
+static void cross_init(struct lockdep_map *lock, int cross)
+{
+ if (cross)
+ ((struct lockdep_map_cross *)lock)->xlock.nr_acquire = 0;
+
+ lock->cross = cross;
+
+ /*
+ * Crossrelease assumes that the ring buffer size of xhlocks
+ * is aligned with power of 2. So force it on build.
+ */
+ BUILD_BUG_ON(MAX_XHLOCKS_NR & (MAX_XHLOCKS_NR - 1));
+}
+
+void lockdep_init_task(struct task_struct *task)
+{
+ int i;
+
+ task->xhlock_idx = UINT_MAX;
+ task->hist_id = 0;
+
+ for (i = 0; i < XHLOCK_CTX_NR; i++) {
+ task->xhlock_idx_hist[i] = UINT_MAX;
+ task->hist_id_save[i] = 0;
+ }
+
+ task->xhlocks = kzalloc(sizeof(struct hist_lock) * MAX_XHLOCKS_NR,
+ GFP_KERNEL);
+}
+
+void lockdep_free_task(struct task_struct *task)
+{
+ if (task->xhlocks) {
+ void *tmp = task->xhlocks;
+ /* Diable crossrelease for current */
+ task->xhlocks = NULL;
+ kfree(tmp);
+ }
+}
+#endif
diff --git a/kernel/locking/lockdep_internals.h b/kernel/locking/lockdep_internals.h
index c08fbd2f5ba9..1da4669d57a7 100644
--- a/kernel/locking/lockdep_internals.h
+++ b/kernel/locking/lockdep_internals.h
@@ -143,6 +143,8 @@ struct lockdep_stats {
int redundant_softirqs_on;
int redundant_softirqs_off;
int nr_unused_locks;
+ int nr_redundant_checks;
+ int nr_redundant;
int nr_cyclic_checks;
int nr_cyclic_check_recursions;
int nr_find_usage_forwards_checks;
diff --git a/kernel/locking/lockdep_proc.c b/kernel/locking/lockdep_proc.c
index 6d1fcc786081..68d9e267ccd4 100644
--- a/kernel/locking/lockdep_proc.c
+++ b/kernel/locking/lockdep_proc.c
@@ -201,6 +201,10 @@ static void lockdep_stats_debug_show(struct seq_file *m)
debug_atomic_read(chain_lookup_hits));
seq_printf(m, " cyclic checks: %11llu\n",
debug_atomic_read(nr_cyclic_checks));
+ seq_printf(m, " redundant checks: %11llu\n",
+ debug_atomic_read(nr_redundant_checks));
+ seq_printf(m, " redundant links: %11llu\n",
+ debug_atomic_read(nr_redundant));
seq_printf(m, " find-mask forwards checks: %11llu\n",
debug_atomic_read(nr_find_usage_forwards_checks));
seq_printf(m, " find-mask backwards checks: %11llu\n",
diff --git a/kernel/locking/lockdep_states.h b/kernel/locking/lockdep_states.h
index 995b0cc2b84c..35ca09f2ed0b 100644
--- a/kernel/locking/lockdep_states.h
+++ b/kernel/locking/lockdep_states.h
@@ -6,4 +6,3 @@
*/
LOCKDEP_STATE(HARDIRQ)
LOCKDEP_STATE(SOFTIRQ)
-LOCKDEP_STATE(RECLAIM_FS)
diff --git a/kernel/locking/osq_lock.c b/kernel/locking/osq_lock.c
index a3167941093b..a74ee6abd039 100644
--- a/kernel/locking/osq_lock.c
+++ b/kernel/locking/osq_lock.c
@@ -109,6 +109,19 @@ bool osq_lock(struct optimistic_spin_queue *lock)
prev = decode_cpu(old);
node->prev = prev;
+
+ /*
+ * osq_lock() unqueue
+ *
+ * node->prev = prev osq_wait_next()
+ * WMB MB
+ * prev->next = node next->prev = prev // unqueue-C
+ *
+ * Here 'node->prev' and 'next->prev' are the same variable and we need
+ * to ensure these stores happen in-order to avoid corrupting the list.
+ */
+ smp_wmb();
+
WRITE_ONCE(prev->next, node);
/*
diff --git a/kernel/locking/qspinlock_paravirt.h b/kernel/locking/qspinlock_paravirt.h
index 4ccfcaae5b89..43555681c40b 100644
--- a/kernel/locking/qspinlock_paravirt.h
+++ b/kernel/locking/qspinlock_paravirt.h
@@ -72,7 +72,7 @@ static inline bool pv_queued_spin_steal_lock(struct qspinlock *lock)
struct __qspinlock *l = (void *)lock;
if (!(atomic_read(&lock->val) & _Q_LOCKED_PENDING_MASK) &&
- (cmpxchg(&l->locked, 0, _Q_LOCKED_VAL) == 0)) {
+ (cmpxchg_acquire(&l->locked, 0, _Q_LOCKED_VAL) == 0)) {
qstat_inc(qstat_pv_lock_stealing, true);
return true;
}
@@ -101,16 +101,16 @@ static __always_inline void clear_pending(struct qspinlock *lock)
/*
* The pending bit check in pv_queued_spin_steal_lock() isn't a memory
- * barrier. Therefore, an atomic cmpxchg() is used to acquire the lock
- * just to be sure that it will get it.
+ * barrier. Therefore, an atomic cmpxchg_acquire() is used to acquire the
+ * lock just to be sure that it will get it.
*/
static __always_inline int trylock_clear_pending(struct qspinlock *lock)
{
struct __qspinlock *l = (void *)lock;
return !READ_ONCE(l->locked) &&
- (cmpxchg(&l->locked_pending, _Q_PENDING_VAL, _Q_LOCKED_VAL)
- == _Q_PENDING_VAL);
+ (cmpxchg_acquire(&l->locked_pending, _Q_PENDING_VAL,
+ _Q_LOCKED_VAL) == _Q_PENDING_VAL);
}
#else /* _Q_PENDING_BITS == 8 */
static __always_inline void set_pending(struct qspinlock *lock)
@@ -138,7 +138,7 @@ static __always_inline int trylock_clear_pending(struct qspinlock *lock)
*/
old = val;
new = (val & ~_Q_PENDING_MASK) | _Q_LOCKED_VAL;
- val = atomic_cmpxchg(&lock->val, old, new);
+ val = atomic_cmpxchg_acquire(&lock->val, old, new);
if (val == old)
return 1;
@@ -362,8 +362,18 @@ static void pv_kick_node(struct qspinlock *lock, struct mcs_spinlock *node)
* observe its next->locked value and advance itself.
*
* Matches with smp_store_mb() and cmpxchg() in pv_wait_node()
+ *
+ * The write to next->locked in arch_mcs_spin_unlock_contended()
+ * must be ordered before the read of pn->state in the cmpxchg()
+ * below for the code to work correctly. To guarantee full ordering
+ * irrespective of the success or failure of the cmpxchg(),
+ * a relaxed version with explicit barrier is used. The control
+ * dependency will order the reading of pn->state before any
+ * subsequent writes.
*/
- if (cmpxchg(&pn->state, vcpu_halted, vcpu_hashed) != vcpu_halted)
+ smp_mb__before_atomic();
+ if (cmpxchg_relaxed(&pn->state, vcpu_halted, vcpu_hashed)
+ != vcpu_halted)
return;
/*
diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h
index 72ad45a9a794..8d039b928d61 100644
--- a/kernel/locking/rtmutex_common.h
+++ b/kernel/locking/rtmutex_common.h
@@ -40,6 +40,9 @@ struct rt_mutex_waiter {
/*
* Various helpers to access the waiters-tree:
*/
+
+#ifdef CONFIG_RT_MUTEXES
+
static inline int rt_mutex_has_waiters(struct rt_mutex *lock)
{
return !RB_EMPTY_ROOT(&lock->waiters);
@@ -69,6 +72,32 @@ task_top_pi_waiter(struct task_struct *p)
pi_tree_entry);
}
+#else
+
+static inline int rt_mutex_has_waiters(struct rt_mutex *lock)
+{
+ return false;
+}
+
+static inline struct rt_mutex_waiter *
+rt_mutex_top_waiter(struct rt_mutex *lock)
+{
+ return NULL;
+}
+
+static inline int task_has_pi_waiters(struct task_struct *p)
+{
+ return false;
+}
+
+static inline struct rt_mutex_waiter *
+task_top_pi_waiter(struct task_struct *p)
+{
+ return NULL;
+}
+
+#endif
+
/*
* lock->owner state tracking:
*/
diff --git a/kernel/locking/rwsem-spinlock.c b/kernel/locking/rwsem-spinlock.c
index 20819df98125..0848634c5512 100644
--- a/kernel/locking/rwsem-spinlock.c
+++ b/kernel/locking/rwsem-spinlock.c
@@ -126,7 +126,7 @@ __rwsem_wake_one_writer(struct rw_semaphore *sem)
/*
* get a read lock on the semaphore
*/
-void __sched __down_read(struct rw_semaphore *sem)
+int __sched __down_read_common(struct rw_semaphore *sem, int state)
{
struct rwsem_waiter waiter;
unsigned long flags;
@@ -140,8 +140,6 @@ void __sched __down_read(struct rw_semaphore *sem)
goto out;
}
- set_current_state(TASK_UNINTERRUPTIBLE);
-
/* set up my own style of waitqueue */
waiter.task = current;
waiter.type = RWSEM_WAITING_FOR_READ;
@@ -149,20 +147,41 @@ void __sched __down_read(struct rw_semaphore *sem)
list_add_tail(&waiter.list, &sem->wait_list);
- /* we don't need to touch the semaphore struct anymore */
- raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
-
/* wait to be given the lock */
for (;;) {
if (!waiter.task)
break;
+ if (signal_pending_state(state, current))
+ goto out_nolock;
+ set_current_state(state);
+ raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
schedule();
- set_current_state(TASK_UNINTERRUPTIBLE);
+ raw_spin_lock_irqsave(&sem->wait_lock, flags);
}
- __set_current_state(TASK_RUNNING);
+ raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
out:
- ;
+ return 0;
+
+out_nolock:
+ /*
+ * We didn't take the lock, so that there is a writer, which
+ * is owner or the first waiter of the sem. If it's a waiter,
+ * it will be woken by current owner. Not need to wake anybody.
+ */
+ list_del(&waiter.list);
+ raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
+ return -EINTR;
+}
+
+void __sched __down_read(struct rw_semaphore *sem)
+{
+ __down_read_common(sem, TASK_UNINTERRUPTIBLE);
+}
+
+int __sched __down_read_killable(struct rw_semaphore *sem)
+{
+ return __down_read_common(sem, TASK_KILLABLE);
}
/*
diff --git a/kernel/locking/rwsem-xadd.c b/kernel/locking/rwsem-xadd.c
index 34e727f18e49..02f660666ab8 100644
--- a/kernel/locking/rwsem-xadd.c
+++ b/kernel/locking/rwsem-xadd.c
@@ -221,8 +221,8 @@ static void __rwsem_mark_wake(struct rw_semaphore *sem,
/*
* Wait for the read lock to be granted
*/
-__visible
-struct rw_semaphore __sched *rwsem_down_read_failed(struct rw_semaphore *sem)
+static inline struct rw_semaphore __sched *
+__rwsem_down_read_failed_common(struct rw_semaphore *sem, int state)
{
long count, adjustment = -RWSEM_ACTIVE_READ_BIAS;
struct rwsem_waiter waiter;
@@ -255,17 +255,44 @@ struct rw_semaphore __sched *rwsem_down_read_failed(struct rw_semaphore *sem)
/* wait to be given the lock */
while (true) {
- set_current_state(TASK_UNINTERRUPTIBLE);
+ set_current_state(state);
if (!waiter.task)
break;
+ if (signal_pending_state(state, current)) {
+ raw_spin_lock_irq(&sem->wait_lock);
+ if (waiter.task)
+ goto out_nolock;
+ raw_spin_unlock_irq(&sem->wait_lock);
+ break;
+ }
schedule();
}
__set_current_state(TASK_RUNNING);
return sem;
+out_nolock:
+ list_del(&waiter.list);
+ if (list_empty(&sem->wait_list))
+ atomic_long_add(-RWSEM_WAITING_BIAS, &sem->count);
+ raw_spin_unlock_irq(&sem->wait_lock);
+ __set_current_state(TASK_RUNNING);
+ return ERR_PTR(-EINTR);
+}
+
+__visible struct rw_semaphore * __sched
+rwsem_down_read_failed(struct rw_semaphore *sem)
+{
+ return __rwsem_down_read_failed_common(sem, TASK_UNINTERRUPTIBLE);
}
EXPORT_SYMBOL(rwsem_down_read_failed);
+__visible struct rw_semaphore * __sched
+rwsem_down_read_failed_killable(struct rw_semaphore *sem)
+{
+ return __rwsem_down_read_failed_common(sem, TASK_KILLABLE);
+}
+EXPORT_SYMBOL(rwsem_down_read_failed_killable);
+
/*
* This function must be called with the sem->wait_lock held to prevent
* race conditions between checking the rwsem wait list and setting the
diff --git a/kernel/panic.c b/kernel/panic.c
index a58932b41700..bdd18afa19a4 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -26,6 +26,7 @@
#include <linux/nmi.h>
#include <linux/console.h>
#include <linux/bug.h>
+#include <linux/ratelimit.h>
#define PANIC_TIMER_STEP 100
#define PANIC_BLINK_SPD 18
@@ -601,6 +602,17 @@ EXPORT_SYMBOL(__stack_chk_fail);
#endif
+#ifdef CONFIG_ARCH_HAS_REFCOUNT
+void refcount_error_report(struct pt_regs *regs, const char *err)
+{
+ WARN_RATELIMIT(1, "refcount_t %s at %pB in %s[%d], uid/euid: %u/%u\n",
+ err, (void *)instruction_pointer(regs),
+ current->comm, task_pid_nr(current),
+ from_kuid_munged(&init_user_ns, current_uid()),
+ from_kuid_munged(&init_user_ns, current_euid()));
+}
+#endif
+
core_param(panic, panic_timeout, int, 0644);
core_param(pause_on_oops, pause_on_oops, int, 0644);
core_param(panic_on_warn, panic_on_warn, int, 0644);
diff --git a/kernel/sched/completion.c b/kernel/sched/completion.c
index 5d9131aa846f..cc873075c3bd 100644
--- a/kernel/sched/completion.c
+++ b/kernel/sched/completion.c
@@ -32,6 +32,12 @@ void complete(struct completion *x)
unsigned long flags;
spin_lock_irqsave(&x->wait.lock, flags);
+
+ /*
+ * Perform commit of crossrelease here.
+ */
+ complete_release_commit(x);
+
if (x->done != UINT_MAX)
x->done++;
__wake_up_locked(&x->wait, TASK_NORMAL, 1);
@@ -99,9 +105,14 @@ __wait_for_common(struct completion *x,
{
might_sleep();
+ complete_acquire(x);
+
spin_lock_irq(&x->wait.lock);
timeout = do_wait_for_common(x, action, timeout, state);
spin_unlock_irq(&x->wait.lock);
+
+ complete_release(x);
+
return timeout;
}
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index c1fcd96cf432..6d2c7ff9ba98 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1972,8 +1972,8 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
* reordered with p->state check below. This pairs with mb() in
* set_current_state() the waiting thread does.
*/
- smp_mb__before_spinlock();
raw_spin_lock_irqsave(&p->pi_lock, flags);
+ smp_mb__after_spinlock();
if (!(p->state & state))
goto out;
@@ -3296,8 +3296,8 @@ static void __sched notrace __schedule(bool preempt)
* can't be reordered with __set_current_state(TASK_INTERRUPTIBLE)
* done by the caller to avoid the race with signal_wake_up().
*/
- smp_mb__before_spinlock();
rq_lock(rq, &rf);
+ smp_mb__after_spinlock();
/* Promote REQ to ACT */
rq->clock_update_flags <<= 1;
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 25e5cb1107f3..ab1c7f5409a0 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -769,7 +769,7 @@ struct rq {
#ifdef CONFIG_SCHED_HRTICK
#ifdef CONFIG_SMP
int hrtick_csd_pending;
- struct call_single_data hrtick_csd;
+ call_single_data_t hrtick_csd;
#endif
struct hrtimer hrtick_timer;
#endif
diff --git a/kernel/sched/swait.c b/kernel/sched/swait.c
index 3d5610dcce11..2227e183e202 100644
--- a/kernel/sched/swait.c
+++ b/kernel/sched/swait.c
@@ -33,9 +33,6 @@ void swake_up(struct swait_queue_head *q)
{
unsigned long flags;
- if (!swait_active(q))
- return;
-
raw_spin_lock_irqsave(&q->lock, flags);
swake_up_locked(q);
raw_spin_unlock_irqrestore(&q->lock, flags);
@@ -51,9 +48,6 @@ void swake_up_all(struct swait_queue_head *q)
struct swait_queue *curr;
LIST_HEAD(tmp);
- if (!swait_active(q))
- return;
-
raw_spin_lock_irq(&q->lock);
list_splice_init(&q->task_list, &tmp);
while (!list_empty(&tmp)) {
diff --git a/kernel/smp.c b/kernel/smp.c
index 3061483cb3ad..81cfca9b4cc3 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -28,7 +28,7 @@ enum {
};
struct call_function_data {
- struct call_single_data __percpu *csd;
+ call_single_data_t __percpu *csd;
cpumask_var_t cpumask;
cpumask_var_t cpumask_ipi;
};
@@ -51,7 +51,7 @@ int smpcfd_prepare_cpu(unsigned int cpu)
free_cpumask_var(cfd->cpumask);
return -ENOMEM;
}
- cfd->csd = alloc_percpu(struct call_single_data);
+ cfd->csd = alloc_percpu(call_single_data_t);
if (!cfd->csd) {
free_cpumask_var(cfd->cpumask);
free_cpumask_var(cfd->cpumask_ipi);
@@ -103,12 +103,12 @@ void __init call_function_init(void)
* previous function call. For multi-cpu calls its even more interesting
* as we'll have to ensure no other cpu is observing our csd.
*/
-static __always_inline void csd_lock_wait(struct call_single_data *csd)
+static __always_inline void csd_lock_wait(call_single_data_t *csd)
{
smp_cond_load_acquire(&csd->flags, !(VAL & CSD_FLAG_LOCK));
}
-static __always_inline void csd_lock(struct call_single_data *csd)
+static __always_inline void csd_lock(call_single_data_t *csd)
{
csd_lock_wait(csd);
csd->flags |= CSD_FLAG_LOCK;
@@ -116,12 +116,12 @@ static __always_inline void csd_lock(struct call_single_data *csd)
/*
* prevent CPU from reordering the above assignment
* to ->flags with any subsequent assignments to other
- * fields of the specified call_single_data structure:
+ * fields of the specified call_single_data_t structure:
*/
smp_wmb();
}
-static __always_inline void csd_unlock(struct call_single_data *csd)
+static __always_inline void csd_unlock(call_single_data_t *csd)
{
WARN_ON(!(csd->flags & CSD_FLAG_LOCK));
@@ -131,14 +131,14 @@ static __always_inline void csd_unlock(struct call_single_data *csd)
smp_store_release(&csd->flags, 0);
}
-static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_single_data, csd_data);
+static DEFINE_PER_CPU_SHARED_ALIGNED(call_single_data_t, csd_data);
/*
- * Insert a previously allocated call_single_data element
+ * Insert a previously allocated call_single_data_t element
* for execution on the given CPU. data must already have
* ->func, ->info, and ->flags set.
*/
-static int generic_exec_single(int cpu, struct call_single_data *csd,
+static int generic_exec_single(int cpu, call_single_data_t *csd,
smp_call_func_t func, void *info)
{
if (cpu == smp_processor_id()) {
@@ -210,7 +210,7 @@ static void flush_smp_call_function_queue(bool warn_cpu_offline)
{
struct llist_head *head;
struct llist_node *entry;
- struct call_single_data *csd, *csd_next;
+ call_single_data_t *csd, *csd_next;
static bool warned;
WARN_ON(!irqs_disabled());
@@ -268,8 +268,10 @@ static void flush_smp_call_function_queue(bool warn_cpu_offline)
int smp_call_function_single(int cpu, smp_call_func_t func, void *info,
int wait)
{
- struct call_single_data *csd;
- struct call_single_data csd_stack = { .flags = CSD_FLAG_LOCK | CSD_FLAG_SYNCHRONOUS };
+ call_single_data_t *csd;
+ call_single_data_t csd_stack = {
+ .flags = CSD_FLAG_LOCK | CSD_FLAG_SYNCHRONOUS,
+ };
int this_cpu;
int err;
@@ -321,7 +323,7 @@ EXPORT_SYMBOL(smp_call_function_single);
* NOTE: Be careful, there is unfortunately no current debugging facility to
* validate the correctness of this serialization.
*/
-int smp_call_function_single_async(int cpu, struct call_single_data *csd)
+int smp_call_function_single_async(int cpu, call_single_data_t *csd)
{
int err = 0;
@@ -444,7 +446,7 @@ void smp_call_function_many(const struct cpumask *mask,
cpumask_clear(cfd->cpumask_ipi);
for_each_cpu(cpu, cfd->cpumask) {
- struct call_single_data *csd = per_cpu_ptr(cfd->csd, cpu);
+ call_single_data_t *csd = per_cpu_ptr(cfd->csd, cpu);
csd_lock(csd);
if (wait)
@@ -460,7 +462,7 @@ void smp_call_function_many(const struct cpumask *mask,
if (wait) {
for_each_cpu(cpu, cfd->cpumask) {
- struct call_single_data *csd;
+ call_single_data_t *csd;
csd = per_cpu_ptr(cfd->csd, cpu);
csd_lock_wait(csd);
diff --git a/kernel/up.c b/kernel/up.c
index ee81ac9af4ca..42c46bf3e0a5 100644
--- a/kernel/up.c
+++ b/kernel/up.c
@@ -23,7 +23,7 @@ int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
}
EXPORT_SYMBOL(smp_call_function_single);
-int smp_call_function_single_async(int cpu, struct call_single_data *csd)
+int smp_call_function_single_async(int cpu, call_single_data_t *csd)
{
unsigned long flags;
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index ca937b0c3a96..ab3c0dc8c7ed 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -2091,8 +2091,30 @@ __acquires(&pool->lock)
spin_unlock_irq(&pool->lock);
- lock_map_acquire_read(&pwq->wq->lockdep_map);
+ lock_map_acquire(&pwq->wq->lockdep_map);
lock_map_acquire(&lockdep_map);
+ /*
+ * Strictly speaking we should mark the invariant state without holding
+ * any locks, that is, before these two lock_map_acquire()'s.
+ *
+ * However, that would result in:
+ *
+ * A(W1)
+ * WFC(C)
+ * A(W1)
+ * C(C)
+ *
+ * Which would create W1->C->W1 dependencies, even though there is no
+ * actual deadlock possible. There are two solutions, using a
+ * read-recursive acquire on the work(queue) 'locks', but this will then
+ * hit the lockdep limitation on recursive locks, or simply discard
+ * these locks.
+ *
+ * AFAICT there is no possible deadlock scenario between the
+ * flush_work() and complete() primitives (except for single-threaded
+ * workqueues), so hiding them isn't a problem.
+ */
+ lockdep_invariant_state(true);
trace_workqueue_execute_start(work);
worker->current_func(work);
/*
@@ -2474,7 +2496,16 @@ static void insert_wq_barrier(struct pool_workqueue *pwq,
*/
INIT_WORK_ONSTACK(&barr->work, wq_barrier_func);
__set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&barr->work));
- init_completion(&barr->done);
+
+ /*
+ * Explicitly init the crosslock for wq_barrier::done, make its lock
+ * key a subkey of the corresponding work. As a result we won't
+ * build a dependency between wq_barrier::done and unrelated work.
+ */
+ lockdep_init_map_crosslock((struct lockdep_map *)&barr->done.map,
+ "(complete)wq_barr::done",
+ target->lockdep_map.key, 1);
+ __init_completion(&barr->done);
barr->task = current;
/*
@@ -2815,16 +2846,18 @@ static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr)
spin_unlock_irq(&pool->lock);
/*
- * If @max_active is 1 or rescuer is in use, flushing another work
- * item on the same workqueue may lead to deadlock. Make sure the
- * flusher is not running on the same workqueue by verifying write
- * access.
+ * Force a lock recursion deadlock when using flush_work() inside a
+ * single-threaded or rescuer equipped workqueue.
+ *
+ * For single threaded workqueues the deadlock happens when the work
+ * is after the work issuing the flush_work(). For rescuer equipped
+ * workqueues the deadlock happens when the rescuer stalls, blocking
+ * forward progress.
*/
- if (pwq->wq->saved_max_active == 1 || pwq->wq->rescuer)
+ if (pwq->wq->saved_max_active == 1 || pwq->wq->rescuer) {
lock_map_acquire(&pwq->wq->lockdep_map);
- else
- lock_map_acquire_read(&pwq->wq->lockdep_map);
- lock_map_release(&pwq->wq->lockdep_map);
+ lock_map_release(&pwq->wq->lockdep_map);
+ }
return true;
already_gone:
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-26 09:11:56 +0000