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authorAndrew Morton <akpm@linux-foundation.org>2016-02-12 03:13:14 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2016-02-12 05:35:48 +0300
commit4a389810bc3cb0e73443104f0827e81e23cb1e12 (patch)
tree00c0ed0ee923222bbf68bc23ed88450120745428
parent6b75d14912f2d89a3539c0b3a100519e1eec9a63 (diff)
downloadlinux-4a389810bc3cb0e73443104f0827e81e23cb1e12.tar.xz
kernel/locking/lockdep.c: convert hash tables to hlists
Mike said: : CONFIG_UBSAN_ALIGNMENT breaks x86-64 kernel with lockdep enabled, i. e : kernel with CONFIG_UBSAN_ALIGNMENT fails to load without even any error : message. : : The problem is that ubsan callbacks use spinlocks and might be called : before lockdep is initialized. Particularly this line in the : reserve_ebda_region function causes problem: : : lowmem = *(unsigned short *)__va(BIOS_LOWMEM_KILOBYTES); : : If i put lockdep_init() before reserve_ebda_region call in : x86_64_start_reservations kernel loads well. Fix this ordering issue permanently: change lockdep so that it uses hlists for the hash tables. Unlike a list_head, an hlist_head is in its initialized state when it is all-zeroes, so lockdep is ready for operation immediately upon boot - lockdep_init() need not have run. The patch will also save some memory. lockdep_init() and lockdep_initialized can be done away with now - a 4.6 patch has been prepared to do this. Reported-by: Mike Krinkin <krinkin.m.u@gmail.com> Suggested-by: Mike Krinkin <krinkin.m.u@gmail.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/linux/lockdep.h4
-rw-r--r--kernel/locking/lockdep.c42
2 files changed, 21 insertions, 25 deletions
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index c57e424d914b..4dca42fd32f5 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -66,7 +66,7 @@ struct lock_class {
/*
* class-hash:
*/
- struct list_head hash_entry;
+ struct hlist_node hash_entry;
/*
* global list of all lock-classes:
@@ -199,7 +199,7 @@ struct lock_chain {
u8 irq_context;
u8 depth;
u16 base;
- struct list_head entry;
+ struct hlist_node entry;
u64 chain_key;
};
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 60ace56618f6..7537e568dabe 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -292,7 +292,7 @@ LIST_HEAD(all_lock_classes);
#define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS)
#define classhashentry(key) (classhash_table + __classhashfn((key)))
-static struct list_head classhash_table[CLASSHASH_SIZE];
+static struct hlist_head classhash_table[CLASSHASH_SIZE];
/*
* We put the lock dependency chains into a hash-table as well, to cache
@@ -303,7 +303,7 @@ static struct list_head classhash_table[CLASSHASH_SIZE];
#define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS)
#define chainhashentry(chain) (chainhash_table + __chainhashfn((chain)))
-static struct list_head chainhash_table[CHAINHASH_SIZE];
+static struct hlist_head chainhash_table[CHAINHASH_SIZE];
/*
* The hash key of the lock dependency chains is a hash itself too:
@@ -666,7 +666,7 @@ static inline struct lock_class *
look_up_lock_class(struct lockdep_map *lock, unsigned int subclass)
{
struct lockdep_subclass_key *key;
- struct list_head *hash_head;
+ struct hlist_head *hash_head;
struct lock_class *class;
#ifdef CONFIG_DEBUG_LOCKDEP
@@ -719,7 +719,7 @@ look_up_lock_class(struct lockdep_map *lock, unsigned int subclass)
if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
return NULL;
- list_for_each_entry_rcu(class, hash_head, hash_entry) {
+ hlist_for_each_entry_rcu(class, hash_head, hash_entry) {
if (class->key == key) {
/*
* Huh! same key, different name? Did someone trample
@@ -742,7 +742,7 @@ static inline struct lock_class *
register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
{
struct lockdep_subclass_key *key;
- struct list_head *hash_head;
+ struct hlist_head *hash_head;
struct lock_class *class;
DEBUG_LOCKS_WARN_ON(!irqs_disabled());
@@ -774,7 +774,7 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
* We have to do the hash-walk again, to avoid races
* with another CPU:
*/
- list_for_each_entry_rcu(class, hash_head, hash_entry) {
+ hlist_for_each_entry_rcu(class, hash_head, hash_entry) {
if (class->key == key)
goto out_unlock_set;
}
@@ -805,7 +805,7 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
* We use RCU's safe list-add method to make
* parallel walking of the hash-list safe:
*/
- list_add_tail_rcu(&class->hash_entry, hash_head);
+ hlist_add_head_rcu(&class->hash_entry, hash_head);
/*
* Add it to the global list of classes:
*/
@@ -2017,7 +2017,7 @@ static inline int lookup_chain_cache(struct task_struct *curr,
u64 chain_key)
{
struct lock_class *class = hlock_class(hlock);
- struct list_head *hash_head = chainhashentry(chain_key);
+ struct hlist_head *hash_head = chainhashentry(chain_key);
struct lock_chain *chain;
struct held_lock *hlock_curr;
int i, j;
@@ -2033,7 +2033,7 @@ static inline int lookup_chain_cache(struct task_struct *curr,
* We can walk it lock-free, because entries only get added
* to the hash:
*/
- list_for_each_entry_rcu(chain, hash_head, entry) {
+ hlist_for_each_entry_rcu(chain, hash_head, entry) {
if (chain->chain_key == chain_key) {
cache_hit:
debug_atomic_inc(chain_lookup_hits);
@@ -2057,7 +2057,7 @@ cache_hit:
/*
* We have to walk the chain again locked - to avoid duplicates:
*/
- list_for_each_entry(chain, hash_head, entry) {
+ hlist_for_each_entry(chain, hash_head, entry) {
if (chain->chain_key == chain_key) {
graph_unlock();
goto cache_hit;
@@ -2091,7 +2091,7 @@ cache_hit:
}
chain_hlocks[chain->base + j] = class - lock_classes;
}
- list_add_tail_rcu(&chain->entry, hash_head);
+ hlist_add_head_rcu(&chain->entry, hash_head);
debug_atomic_inc(chain_lookup_misses);
inc_chains();
@@ -3875,7 +3875,7 @@ void lockdep_reset(void)
nr_process_chains = 0;
debug_locks = 1;
for (i = 0; i < CHAINHASH_SIZE; i++)
- INIT_LIST_HEAD(chainhash_table + i);
+ INIT_HLIST_HEAD(chainhash_table + i);
raw_local_irq_restore(flags);
}
@@ -3894,7 +3894,7 @@ static void zap_class(struct lock_class *class)
/*
* Unhash the class and remove it from the all_lock_classes list:
*/
- list_del_rcu(&class->hash_entry);
+ hlist_del_rcu(&class->hash_entry);
list_del_rcu(&class->lock_entry);
RCU_INIT_POINTER(class->key, NULL);
@@ -3917,7 +3917,7 @@ static inline int within(const void *addr, void *start, unsigned long size)
void lockdep_free_key_range(void *start, unsigned long size)
{
struct lock_class *class;
- struct list_head *head;
+ struct hlist_head *head;
unsigned long flags;
int i;
int locked;
@@ -3930,9 +3930,7 @@ void lockdep_free_key_range(void *start, unsigned long size)
*/
for (i = 0; i < CLASSHASH_SIZE; i++) {
head = classhash_table + i;
- if (list_empty(head))
- continue;
- list_for_each_entry_rcu(class, head, hash_entry) {
+ hlist_for_each_entry_rcu(class, head, hash_entry) {
if (within(class->key, start, size))
zap_class(class);
else if (within(class->name, start, size))
@@ -3962,7 +3960,7 @@ void lockdep_free_key_range(void *start, unsigned long size)
void lockdep_reset_lock(struct lockdep_map *lock)
{
struct lock_class *class;
- struct list_head *head;
+ struct hlist_head *head;
unsigned long flags;
int i, j;
int locked;
@@ -3987,9 +3985,7 @@ void lockdep_reset_lock(struct lockdep_map *lock)
locked = graph_lock();
for (i = 0; i < CLASSHASH_SIZE; i++) {
head = classhash_table + i;
- if (list_empty(head))
- continue;
- list_for_each_entry_rcu(class, head, hash_entry) {
+ hlist_for_each_entry_rcu(class, head, hash_entry) {
int match = 0;
for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++)
@@ -4027,10 +4023,10 @@ void lockdep_init(void)
return;
for (i = 0; i < CLASSHASH_SIZE; i++)
- INIT_LIST_HEAD(classhash_table + i);
+ INIT_HLIST_HEAD(classhash_table + i);
for (i = 0; i < CHAINHASH_SIZE; i++)
- INIT_LIST_HEAD(chainhash_table + i);
+ INIT_HLIST_HEAD(chainhash_table + i);
lockdep_initialized = 1;
}