[GIT PULL] core kernel fixes
From: Ingo Molnar
Date: Thu Aug 04 2011 - 16:46:52 EST
Linus,
Please pull the latest core-urgent-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git core-urgent-for-linus
Thanks,
Ingo
------------------>
Peter Zijlstra (4):
lockdep: Fix trace_hardirqs_on_caller()
lockdep: Fix up warning
slab, lockdep: Annotate slab -> rcu -> debug_object -> slab
slab, lockdep: Annotate the locks before using them
Shawn Bohrer (1):
futex: Fix regression with read only mappings
Tejun Heo (1):
lockdep: Clear whole lockdep_map on initialization
kernel/futex.c | 54 ++++++++++++++++++++++++-------
kernel/lockdep.c | 37 ++++++++++-----------
mm/slab.c | 92 +++++++++++++++++++++++++++++++++++++++++------------
3 files changed, 131 insertions(+), 52 deletions(-)
diff --git a/kernel/futex.c b/kernel/futex.c
index 0a30897..11cbe05 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -218,6 +218,8 @@ static void drop_futex_key_refs(union futex_key *key)
* @uaddr: virtual address of the futex
* @fshared: 0 for a PROCESS_PRIVATE futex, 1 for PROCESS_SHARED
* @key: address where result is stored.
+ * @rw: mapping needs to be read/write (values: VERIFY_READ,
+ * VERIFY_WRITE)
*
* Returns a negative error code or 0
* The key words are stored in *key on success.
@@ -229,12 +231,12 @@ static void drop_futex_key_refs(union futex_key *key)
* lock_page() might sleep, the caller should not hold a spinlock.
*/
static int
-get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key)
+get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key, int rw)
{
unsigned long address = (unsigned long)uaddr;
struct mm_struct *mm = current->mm;
struct page *page, *page_head;
- int err;
+ int err, ro = 0;
/*
* The futex address must be "naturally" aligned.
@@ -262,8 +264,18 @@ get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key)
again:
err = get_user_pages_fast(address, 1, 1, &page);
+ /*
+ * If write access is not required (eg. FUTEX_WAIT), try
+ * and get read-only access.
+ */
+ if (err == -EFAULT && rw == VERIFY_READ) {
+ err = get_user_pages_fast(address, 1, 0, &page);
+ ro = 1;
+ }
if (err < 0)
return err;
+ else
+ err = 0;
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
page_head = page;
@@ -305,6 +317,13 @@ again:
if (!page_head->mapping) {
unlock_page(page_head);
put_page(page_head);
+ /*
+ * ZERO_PAGE pages don't have a mapping. Avoid a busy loop
+ * trying to find one. RW mapping would have COW'd (and thus
+ * have a mapping) so this page is RO and won't ever change.
+ */
+ if ((page_head == ZERO_PAGE(address)))
+ return -EFAULT;
goto again;
}
@@ -316,6 +335,15 @@ again:
* the object not the particular process.
*/
if (PageAnon(page_head)) {
+ /*
+ * A RO anonymous page will never change and thus doesn't make
+ * sense for futex operations.
+ */
+ if (ro) {
+ err = -EFAULT;
+ goto out;
+ }
+
key->both.offset |= FUT_OFF_MMSHARED; /* ref taken on mm */
key->private.mm = mm;
key->private.address = address;
@@ -327,9 +355,10 @@ again:
get_futex_key_refs(key);
+out:
unlock_page(page_head);
put_page(page_head);
- return 0;
+ return err;
}
static inline void put_futex_key(union futex_key *key)
@@ -940,7 +969,7 @@ futex_wake(u32 __user *uaddr, unsigned int flags, int nr_wake, u32 bitset)
if (!bitset)
return -EINVAL;
- ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &key);
+ ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &key, VERIFY_READ);
if (unlikely(ret != 0))
goto out;
@@ -986,10 +1015,10 @@ futex_wake_op(u32 __user *uaddr1, unsigned int flags, u32 __user *uaddr2,
int ret, op_ret;
retry:
- ret = get_futex_key(uaddr1, flags & FLAGS_SHARED, &key1);
+ ret = get_futex_key(uaddr1, flags & FLAGS_SHARED, &key1, VERIFY_READ);
if (unlikely(ret != 0))
goto out;
- ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2);
+ ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2, VERIFY_WRITE);
if (unlikely(ret != 0))
goto out_put_key1;
@@ -1243,10 +1272,11 @@ retry:
pi_state = NULL;
}
- ret = get_futex_key(uaddr1, flags & FLAGS_SHARED, &key1);
+ ret = get_futex_key(uaddr1, flags & FLAGS_SHARED, &key1, VERIFY_READ);
if (unlikely(ret != 0))
goto out;
- ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2);
+ ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2,
+ requeue_pi ? VERIFY_WRITE : VERIFY_READ);
if (unlikely(ret != 0))
goto out_put_key1;
@@ -1790,7 +1820,7 @@ static int futex_wait_setup(u32 __user *uaddr, u32 val, unsigned int flags,
* while the syscall executes.
*/
retry:
- ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &q->key);
+ ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &q->key, VERIFY_READ);
if (unlikely(ret != 0))
return ret;
@@ -1941,7 +1971,7 @@ static int futex_lock_pi(u32 __user *uaddr, unsigned int flags, int detect,
}
retry:
- ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &q.key);
+ ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &q.key, VERIFY_WRITE);
if (unlikely(ret != 0))
goto out;
@@ -2060,7 +2090,7 @@ retry:
if ((uval & FUTEX_TID_MASK) != vpid)
return -EPERM;
- ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &key);
+ ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &key, VERIFY_WRITE);
if (unlikely(ret != 0))
goto out;
@@ -2249,7 +2279,7 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
debug_rt_mutex_init_waiter(&rt_waiter);
rt_waiter.task = NULL;
- ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2);
+ ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2, VERIFY_WRITE);
if (unlikely(ret != 0))
goto out;
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 3956f51..8c24294 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -2468,7 +2468,7 @@ mark_held_locks(struct task_struct *curr, enum mark_type mark)
BUG_ON(usage_bit >= LOCK_USAGE_STATES);
- if (hlock_class(hlock)->key == &__lockdep_no_validate__)
+ if (hlock_class(hlock)->key == __lockdep_no_validate__.subkeys)
continue;
if (!mark_lock(curr, hlock, usage_bit))
@@ -2485,23 +2485,9 @@ static void __trace_hardirqs_on_caller(unsigned long ip)
{
struct task_struct *curr = current;
- if (DEBUG_LOCKS_WARN_ON(unlikely(early_boot_irqs_disabled)))
- return;
-
- if (unlikely(curr->hardirqs_enabled)) {
- /*
- * Neither irq nor preemption are disabled here
- * so this is racy by nature but losing one hit
- * in a stat is not a big deal.
- */
- __debug_atomic_inc(redundant_hardirqs_on);
- return;
- }
/* we'll do an OFF -> ON transition: */
curr->hardirqs_enabled = 1;
- if (DEBUG_LOCKS_WARN_ON(current->hardirq_context))
- return;
/*
* We are going to turn hardirqs on, so set the
* usage bit for all held locks:
@@ -2529,9 +2515,25 @@ void trace_hardirqs_on_caller(unsigned long ip)
if (unlikely(!debug_locks || current->lockdep_recursion))
return;
+ if (unlikely(current->hardirqs_enabled)) {
+ /*
+ * Neither irq nor preemption are disabled here
+ * so this is racy by nature but losing one hit
+ * in a stat is not a big deal.
+ */
+ __debug_atomic_inc(redundant_hardirqs_on);
+ return;
+ }
+
if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
return;
+ if (DEBUG_LOCKS_WARN_ON(unlikely(early_boot_irqs_disabled)))
+ return;
+
+ if (DEBUG_LOCKS_WARN_ON(current->hardirq_context))
+ return;
+
current->lockdep_recursion = 1;
__trace_hardirqs_on_caller(ip);
current->lockdep_recursion = 0;
@@ -2872,10 +2874,7 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this,
void lockdep_init_map(struct lockdep_map *lock, const char *name,
struct lock_class_key *key, int subclass)
{
- int i;
-
- for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++)
- lock->class_cache[i] = NULL;
+ memset(lock, 0, sizeof(*lock));
#ifdef CONFIG_LOCK_STAT
lock->cpu = raw_smp_processor_id();
diff --git a/mm/slab.c b/mm/slab.c
index 9594740..6d90a09 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -622,6 +622,51 @@ int slab_is_available(void)
static struct lock_class_key on_slab_l3_key;
static struct lock_class_key on_slab_alc_key;
+static struct lock_class_key debugobj_l3_key;
+static struct lock_class_key debugobj_alc_key;
+
+static void slab_set_lock_classes(struct kmem_cache *cachep,
+ struct lock_class_key *l3_key, struct lock_class_key *alc_key,
+ int q)
+{
+ struct array_cache **alc;
+ struct kmem_list3 *l3;
+ int r;
+
+ l3 = cachep->nodelists[q];
+ if (!l3)
+ return;
+
+ lockdep_set_class(&l3->list_lock, l3_key);
+ alc = l3->alien;
+ /*
+ * FIXME: This check for BAD_ALIEN_MAGIC
+ * should go away when common slab code is taught to
+ * work even without alien caches.
+ * Currently, non NUMA code returns BAD_ALIEN_MAGIC
+ * for alloc_alien_cache,
+ */
+ if (!alc || (unsigned long)alc == BAD_ALIEN_MAGIC)
+ return;
+ for_each_node(r) {
+ if (alc[r])
+ lockdep_set_class(&alc[r]->lock, alc_key);
+ }
+}
+
+static void slab_set_debugobj_lock_classes_node(struct kmem_cache *cachep, int node)
+{
+ slab_set_lock_classes(cachep, &debugobj_l3_key, &debugobj_alc_key, node);
+}
+
+static void slab_set_debugobj_lock_classes(struct kmem_cache *cachep)
+{
+ int node;
+
+ for_each_online_node(node)
+ slab_set_debugobj_lock_classes_node(cachep, node);
+}
+
static void init_node_lock_keys(int q)
{
struct cache_sizes *s = malloc_sizes;
@@ -630,29 +675,14 @@ static void init_node_lock_keys(int q)
return;
for (s = malloc_sizes; s->cs_size != ULONG_MAX; s++) {
- struct array_cache **alc;
struct kmem_list3 *l3;
- int r;
l3 = s->cs_cachep->nodelists[q];
if (!l3 || OFF_SLAB(s->cs_cachep))
continue;
- lockdep_set_class(&l3->list_lock, &on_slab_l3_key);
- alc = l3->alien;
- /*
- * FIXME: This check for BAD_ALIEN_MAGIC
- * should go away when common slab code is taught to
- * work even without alien caches.
- * Currently, non NUMA code returns BAD_ALIEN_MAGIC
- * for alloc_alien_cache,
- */
- if (!alc || (unsigned long)alc == BAD_ALIEN_MAGIC)
- continue;
- for_each_node(r) {
- if (alc[r])
- lockdep_set_class(&alc[r]->lock,
- &on_slab_alc_key);
- }
+
+ slab_set_lock_classes(s->cs_cachep, &on_slab_l3_key,
+ &on_slab_alc_key, q);
}
}
@@ -671,6 +701,14 @@ static void init_node_lock_keys(int q)
static inline void init_lock_keys(void)
{
}
+
+static void slab_set_debugobj_lock_classes_node(struct kmem_cache *cachep, int node)
+{
+}
+
+static void slab_set_debugobj_lock_classes(struct kmem_cache *cachep)
+{
+}
#endif
/*
@@ -1264,6 +1302,8 @@ static int __cpuinit cpuup_prepare(long cpu)
spin_unlock_irq(&l3->list_lock);
kfree(shared);
free_alien_cache(alien);
+ if (cachep->flags & SLAB_DEBUG_OBJECTS)
+ slab_set_debugobj_lock_classes_node(cachep, node);
}
init_node_lock_keys(node);
@@ -1626,6 +1666,9 @@ void __init kmem_cache_init_late(void)
{
struct kmem_cache *cachep;
+ /* Annotate slab for lockdep -- annotate the malloc caches */
+ init_lock_keys();
+
/* 6) resize the head arrays to their final sizes */
mutex_lock(&cache_chain_mutex);
list_for_each_entry(cachep, &cache_chain, next)
@@ -1636,9 +1679,6 @@ void __init kmem_cache_init_late(void)
/* Done! */
g_cpucache_up = FULL;
- /* Annotate slab for lockdep -- annotate the malloc caches */
- init_lock_keys();
-
/*
* Register a cpu startup notifier callback that initializes
* cpu_cache_get for all new cpus
@@ -2426,6 +2466,16 @@ kmem_cache_create (const char *name, size_t size, size_t align,
goto oops;
}
+ if (flags & SLAB_DEBUG_OBJECTS) {
+ /*
+ * Would deadlock through slab_destroy()->call_rcu()->
+ * debug_object_activate()->kmem_cache_alloc().
+ */
+ WARN_ON_ONCE(flags & SLAB_DESTROY_BY_RCU);
+
+ slab_set_debugobj_lock_classes(cachep);
+ }
+
/* cache setup completed, link it into the list */
list_add(&cachep->next, &cache_chain);
oops:
--
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