[ANNOUNCE] v5.0.21-rt14

From: Sebastian Andrzej Siewior
Date: Wed Jun 26 2019 - 12:18:58 EST

Dear RT folks!

I'm pleased to announce the v5.0.21-rt14 patch set.

Changes since v5.0.21-rt13:

- Fix a "scheduling while atomic" in zswap. Patch by Luis Claudio R.
Goncalves.

- Replace a fix for for wait_for_completion() (introduced in
v5.0.14-rt9) by an alternative version as suggested by Peter
Zijlstra.

- Major futex/rtmutex surgery. He Zhe reported that glibc's
tst-robustpi8.c triggers a BUG() statement. To address that bug the
hash bucket has been made a raw_spinlock_t.

- Two x86 FPU patches from upstream to avoid fallout on 32bit and with
CRIU.

Known issues
- rcutorture is currently broken on -RT. Reported by Juri Lelli.

The delta patch against v5.0.21-rt13 is appended below and can be found here:

https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.0/incr/patch-5.0.21-rt13-rt14.patch.xz

You can get this release via the git tree at:

git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git v5.0.21-rt14

The RT patch against v5.0.21 can be found here:

https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.0/older/patch-5.0.21-rt14.patch.xz

The split quilt queue is available at:

https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.0/older/patches-5.0.21-rt14.tar.xz

Sebastian

diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index a4715458e972f..c1bb7f276d23b 100644
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -5,6 +5,7 @@

#include <linux/compat.h>
#include <linux/cpu.h>
+#include <linux/pagemap.h>

#include <asm/fpu/internal.h>
#include <asm/fpu/signal.h>
@@ -61,6 +62,11 @@ static inline int save_fsave_header(struct task_struct *tsk, void __user *buf)
struct user_i387_ia32_struct env;
struct _fpstate_32 __user *fp = buf;

+ fpregs_lock();
+ if (!test_thread_flag(TIF_NEED_FPU_LOAD))
+ copy_fxregs_to_kernel(&tsk->thread.fpu);
+ fpregs_unlock();
+
convert_from_fxsr(&env, tsk);

if (__copy_to_user(buf, &env, sizeof(env)) ||
@@ -189,15 +195,7 @@ int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size)
fpregs_unlock();

if (ret) {
- int aligned_size;
- int nr_pages;
-
- aligned_size = offset_in_page(buf_fx) + fpu_user_xstate_size;
- nr_pages = DIV_ROUND_UP(aligned_size, PAGE_SIZE);
-
- ret = get_user_pages_unlocked((unsigned long)buf_fx, nr_pages,
- NULL, FOLL_WRITE);
- if (ret == nr_pages)
+ if (!fault_in_pages_writeable(buf_fx, fpu_user_xstate_size))
goto retry;
return -EFAULT;
}
diff --git a/include/linux/swait.h b/include/linux/swait.h
index 21ae66cd41d30..2ac63a13d26d3 100644
--- a/include/linux/swait.h
+++ b/include/linux/swait.h
@@ -61,11 +61,13 @@ struct swait_queue_head {
struct swait_queue {
struct task_struct *task;
struct list_head task_list;
+ unsigned int remove;
};

#define __SWAITQUEUE_INITIALIZER(name) { \
.task = current, \
.task_list = LIST_HEAD_INIT((name).task_list), \
+ .remove = 1, \
}

#define DECLARE_SWAITQUEUE(name) \
diff --git a/kernel/futex.c b/kernel/futex.c
index 85c538fcad578..a86955d80f7b9 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -243,7 +243,7 @@ struct futex_q {
struct plist_node list;

struct task_struct *task;
- spinlock_t *lock_ptr;
+ raw_spinlock_t *lock_ptr;
union futex_key key;
struct futex_pi_state *pi_state;
struct rt_mutex_waiter *rt_waiter;
@@ -264,7 +264,7 @@ static const struct futex_q futex_q_init = {
*/
struct futex_hash_bucket {
atomic_t waiters;
- spinlock_t lock;
+ raw_spinlock_t lock;
struct plist_head chain;
} ____cacheline_aligned_in_smp;

@@ -830,13 +830,13 @@ static void get_pi_state(struct futex_pi_state *pi_state)
* Drops a reference to the pi_state object and frees or caches it
* when the last reference is gone.
*/
-static void put_pi_state(struct futex_pi_state *pi_state)
+static struct futex_pi_state *__put_pi_state(struct futex_pi_state *pi_state)
{
if (!pi_state)
- return;
+ return NULL;

if (!atomic_dec_and_test(&pi_state->refcount))
- return;
+ return NULL;

/*
* If pi_state->owner is NULL, the owner is most probably dying
@@ -856,9 +856,7 @@ static void put_pi_state(struct futex_pi_state *pi_state)
raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
}

- if (current->pi_state_cache) {
- kfree(pi_state);
- } else {
+ if (!current->pi_state_cache) {
/*
* pi_state->list is already empty.
* clear pi_state->owner.
@@ -867,6 +865,30 @@ static void put_pi_state(struct futex_pi_state *pi_state)
pi_state->owner = NULL;
atomic_set(&pi_state->refcount, 1);
current->pi_state_cache = pi_state;
+ pi_state = NULL;
+ }
+ return pi_state;
+}
+
+static void put_pi_state(struct futex_pi_state *pi_state)
+{
+ kfree(__put_pi_state(pi_state));
+}
+
+static void put_pi_state_atomic(struct futex_pi_state *pi_state,
+ struct list_head *to_free)
+{
+ if (__put_pi_state(pi_state))
+ list_add(&pi_state->list, to_free);
+}
+
+static void free_pi_state_list(struct list_head *to_free)
+{
+ struct futex_pi_state *p, *next;
+
+ list_for_each_entry_safe(p, next, to_free, list) {
+ list_del(&p->list);
+ kfree(p);
}
}

@@ -883,6 +905,7 @@ void exit_pi_state_list(struct task_struct *curr)
struct futex_pi_state *pi_state;
struct futex_hash_bucket *hb;
union futex_key key = FUTEX_KEY_INIT;
+ LIST_HEAD(to_free);

if (!futex_cmpxchg_enabled)
return;
@@ -916,7 +939,7 @@ void exit_pi_state_list(struct task_struct *curr)
}
raw_spin_unlock_irq(&curr->pi_lock);

- spin_lock(&hb->lock);
+ raw_spin_lock(&hb->lock);
raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
raw_spin_lock(&curr->pi_lock);
/*
@@ -926,10 +949,8 @@ void exit_pi_state_list(struct task_struct *curr)
if (head->next != next) {
/* retain curr->pi_lock for the loop invariant */
raw_spin_unlock(&pi_state->pi_mutex.wait_lock);
- raw_spin_unlock_irq(&curr->pi_lock);
- spin_unlock(&hb->lock);
- raw_spin_lock_irq(&curr->pi_lock);
- put_pi_state(pi_state);
+ raw_spin_unlock(&hb->lock);
+ put_pi_state_atomic(pi_state, &to_free);
continue;
}

@@ -940,7 +961,7 @@ void exit_pi_state_list(struct task_struct *curr)

raw_spin_unlock(&curr->pi_lock);
raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
- spin_unlock(&hb->lock);
+ raw_spin_unlock(&hb->lock);

rt_mutex_futex_unlock(&pi_state->pi_mutex);
put_pi_state(pi_state);
@@ -948,6 +969,8 @@ void exit_pi_state_list(struct task_struct *curr)
raw_spin_lock_irq(&curr->pi_lock);
}
raw_spin_unlock_irq(&curr->pi_lock);
+
+ free_pi_state_list(&to_free);
}

#endif
@@ -1562,21 +1585,21 @@ static inline void
double_lock_hb(struct futex_hash_bucket *hb1, struct futex_hash_bucket *hb2)
{
if (hb1 <= hb2) {
- spin_lock(&hb1->lock);
+ raw_spin_lock(&hb1->lock);
if (hb1 < hb2)
- spin_lock_nested(&hb2->lock, SINGLE_DEPTH_NESTING);
+ raw_spin_lock_nested(&hb2->lock, SINGLE_DEPTH_NESTING);
} else { /* hb1 > hb2 */
- spin_lock(&hb2->lock);
- spin_lock_nested(&hb1->lock, SINGLE_DEPTH_NESTING);
+ raw_spin_lock(&hb2->lock);
+ raw_spin_lock_nested(&hb1->lock, SINGLE_DEPTH_NESTING);
}
}

static inline void
double_unlock_hb(struct futex_hash_bucket *hb1, struct futex_hash_bucket *hb2)
{
- spin_unlock(&hb1->lock);
+ raw_spin_unlock(&hb1->lock);
if (hb1 != hb2)
- spin_unlock(&hb2->lock);
+ raw_spin_unlock(&hb2->lock);
}

/*
@@ -1604,7 +1627,7 @@ futex_wake(u32 __user *uaddr, unsigned int flags, int nr_wake, u32 bitset)
if (!hb_waiters_pending(hb))
goto out_put_key;

- spin_lock(&hb->lock);
+ raw_spin_lock(&hb->lock);

plist_for_each_entry_safe(this, next, &hb->chain, list) {
if (match_futex (&this->key, &key)) {
@@ -1623,7 +1646,7 @@ futex_wake(u32 __user *uaddr, unsigned int flags, int nr_wake, u32 bitset)
}
}

- spin_unlock(&hb->lock);
+ raw_spin_unlock(&hb->lock);
wake_up_q(&wake_q);
out_put_key:
put_futex_key(&key);
@@ -1930,6 +1953,7 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags,
struct futex_hash_bucket *hb1, *hb2;
struct futex_q *this, *next;
DEFINE_WAKE_Q(wake_q);
+ LIST_HEAD(to_free);

if (nr_wake < 0 || nr_requeue < 0)
return -EINVAL;
@@ -2157,16 +2181,6 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags,
requeue_pi_wake_futex(this, &key2, hb2);
drop_count++;
continue;
- } else if (ret == -EAGAIN) {
- /*
- * Waiter was woken by timeout or
- * signal and has set pi_blocked_on to
- * PI_WAKEUP_INPROGRESS before we
- * tried to enqueue it on the rtmutex.
- */
- this->pi_state = NULL;
- put_pi_state(pi_state);
- continue;
} else if (ret) {
/*
* rt_mutex_start_proxy_lock() detected a
@@ -2177,7 +2191,7 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags,
* object.
*/
this->pi_state = NULL;
- put_pi_state(pi_state);
+ put_pi_state_atomic(pi_state, &to_free);
/*
* We stop queueing more waiters and let user
* space deal with the mess.
@@ -2194,7 +2208,7 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags,
* in futex_proxy_trylock_atomic() or in lookup_pi_state(). We
* need to drop it here again.
*/
- put_pi_state(pi_state);
+ put_pi_state_atomic(pi_state, &to_free);

out_unlock:
double_unlock_hb(hb1, hb2);
@@ -2215,6 +2229,7 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags,
out_put_key1:
put_futex_key(&key1);
out:
+ free_pi_state_list(&to_free);
return ret ? ret : task_count;
}

@@ -2238,7 +2253,7 @@ static inline struct futex_hash_bucket *queue_lock(struct futex_q *q)

q->lock_ptr = &hb->lock;

- spin_lock(&hb->lock);
+ raw_spin_lock(&hb->lock);
return hb;
}

@@ -2246,7 +2261,7 @@ static inline void
queue_unlock(struct futex_hash_bucket *hb)
__releases(&hb->lock)
{
- spin_unlock(&hb->lock);
+ raw_spin_unlock(&hb->lock);
hb_waiters_dec(hb);
}

@@ -2285,7 +2300,7 @@ static inline void queue_me(struct futex_q *q, struct futex_hash_bucket *hb)
__releases(&hb->lock)
{
__queue_me(q, hb);
- spin_unlock(&hb->lock);
+ raw_spin_unlock(&hb->lock);
}

/**
@@ -2301,41 +2316,41 @@ static inline void queue_me(struct futex_q *q, struct futex_hash_bucket *hb)
*/
static int unqueue_me(struct futex_q *q)
{
- spinlock_t *lock_ptr;
+ raw_spinlock_t *lock_ptr;
int ret = 0;

/* In the common case we don't take the spinlock, which is nice. */
retry:
/*
- * q->lock_ptr can change between this read and the following spin_lock.
- * Use READ_ONCE to forbid the compiler from reloading q->lock_ptr and
- * optimizing lock_ptr out of the logic below.
+ * q->lock_ptr can change between this read and the following
+ * raw_spin_lock. Use READ_ONCE to forbid the compiler from reloading
+ * q->lock_ptr and optimizing lock_ptr out of the logic below.
*/
lock_ptr = READ_ONCE(q->lock_ptr);
if (lock_ptr != NULL) {
- spin_lock(lock_ptr);
+ raw_spin_lock(lock_ptr);
/*
* q->lock_ptr can change between reading it and
- * spin_lock(), causing us to take the wrong lock. This
+ * raw_spin_lock(), causing us to take the wrong lock. This
* corrects the race condition.
*
* Reasoning goes like this: if we have the wrong lock,
* q->lock_ptr must have changed (maybe several times)
- * between reading it and the spin_lock(). It can
- * change again after the spin_lock() but only if it was
- * already changed before the spin_lock(). It cannot,
+ * between reading it and the raw_spin_lock(). It can
+ * change again after the raw_spin_lock() but only if it was
+ * already changed before the raw_spin_lock(). It cannot,
* however, change back to the original value. Therefore
* we can detect whether we acquired the correct lock.
*/
if (unlikely(lock_ptr != q->lock_ptr)) {
- spin_unlock(lock_ptr);
+ raw_spin_unlock(lock_ptr);
goto retry;
}
__unqueue_futex(q);

BUG_ON(q->pi_state);

- spin_unlock(lock_ptr);
+ raw_spin_unlock(lock_ptr);
ret = 1;
}

@@ -2351,13 +2366,16 @@ static int unqueue_me(struct futex_q *q)
static void unqueue_me_pi(struct futex_q *q)
__releases(q->lock_ptr)
{
+ struct futex_pi_state *ps;
+
__unqueue_futex(q);

BUG_ON(!q->pi_state);
- put_pi_state(q->pi_state);
+ ps = __put_pi_state(q->pi_state);
q->pi_state = NULL;

- spin_unlock(q->lock_ptr);
+ raw_spin_unlock(q->lock_ptr);
+ kfree(ps);
}

static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
@@ -2490,7 +2508,7 @@ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
*/
handle_err:
raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
- spin_unlock(q->lock_ptr);
+ raw_spin_unlock(q->lock_ptr);

switch (err) {
case -EFAULT:
@@ -2508,7 +2526,7 @@ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
break;
}

- spin_lock(q->lock_ptr);
+ raw_spin_lock(q->lock_ptr);
raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);

/*
@@ -2604,7 +2622,7 @@ static void futex_wait_queue_me(struct futex_hash_bucket *hb, struct futex_q *q,
/*
* The task state is guaranteed to be set before another task can
* wake it. set_current_state() is implemented using smp_store_mb() and
- * queue_me() calls spin_unlock() upon completion, both serializing
+ * queue_me() calls raw_spin_unlock() upon completion, both serializing
* access to the hash list and forcing another memory barrier.
*/
set_current_state(TASK_INTERRUPTIBLE);
@@ -2895,15 +2913,7 @@ static int futex_lock_pi(u32 __user *uaddr, unsigned int flags,
* before __rt_mutex_start_proxy_lock() is done.
*/
raw_spin_lock_irq(&q.pi_state->pi_mutex.wait_lock);
- /*
- * the migrate_disable() here disables migration in the in_atomic() fast
- * path which is enabled again in the following spin_unlock(). We have
- * one migrate_disable() pending in the slow-path which is reversed
- * after the raw_spin_unlock_irq() where we leave the atomic context.
- */
- migrate_disable();
-
- spin_unlock(q.lock_ptr);
+ raw_spin_unlock(q.lock_ptr);
/*
* __rt_mutex_start_proxy_lock() unconditionally enqueues the @rt_waiter
* such that futex_unlock_pi() is guaranteed to observe the waiter when
@@ -2911,7 +2921,6 @@ static int futex_lock_pi(u32 __user *uaddr, unsigned int flags,
*/
ret = __rt_mutex_start_proxy_lock(&q.pi_state->pi_mutex, &rt_waiter, current);
raw_spin_unlock_irq(&q.pi_state->pi_mutex.wait_lock);
- migrate_enable();

if (ret) {
if (ret == 1)
@@ -2925,7 +2934,7 @@ static int futex_lock_pi(u32 __user *uaddr, unsigned int flags,
ret = rt_mutex_wait_proxy_lock(&q.pi_state->pi_mutex, to, &rt_waiter);

cleanup:
- spin_lock(q.lock_ptr);
+ raw_spin_lock(q.lock_ptr);
/*
* If we failed to acquire the lock (deadlock/signal/timeout), we must
* first acquire the hb->lock before removing the lock from the
@@ -3026,7 +3035,7 @@ static int futex_unlock_pi(u32 __user *uaddr, unsigned int flags)
return ret;

hb = hash_futex(&key);
- spin_lock(&hb->lock);
+ raw_spin_lock(&hb->lock);

/*
* Check waiters first. We do not trust user space values at
@@ -3060,19 +3069,10 @@ static int futex_unlock_pi(u32 __user *uaddr, unsigned int flags)
* rt_waiter. Also see the WARN in wake_futex_pi().
*/
raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
- /*
- * Magic trickery for now to make the RT migrate disable
- * logic happy. The following spin_unlock() happens with
- * interrupts disabled so the internal migrate_enable()
- * won't undo the migrate_disable() which was issued when
- * locking hb->lock.
- */
- migrate_disable();
- spin_unlock(&hb->lock);
+ raw_spin_unlock(&hb->lock);

/* drops pi_state->pi_mutex.wait_lock */
ret = wake_futex_pi(uaddr, uval, pi_state);
- migrate_enable();

put_pi_state(pi_state);

@@ -3108,7 +3108,7 @@ static int futex_unlock_pi(u32 __user *uaddr, unsigned int flags)
* owner.
*/
if ((ret = cmpxchg_futex_value_locked(&curval, uaddr, uval, 0))) {
- spin_unlock(&hb->lock);
+ raw_spin_unlock(&hb->lock);
switch (ret) {
case -EFAULT:
goto pi_faulted;
@@ -3128,7 +3128,7 @@ static int futex_unlock_pi(u32 __user *uaddr, unsigned int flags)
ret = (curval == uval) ? 0 : -EAGAIN;

out_unlock:
- spin_unlock(&hb->lock);
+ raw_spin_unlock(&hb->lock);
out_putkey:
put_futex_key(&key);
return ret;
@@ -3244,7 +3244,7 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
struct hrtimer_sleeper timeout, *to = NULL;
struct futex_pi_state *pi_state = NULL;
struct rt_mutex_waiter rt_waiter;
- struct futex_hash_bucket *hb, *hb2;
+ struct futex_hash_bucket *hb;
union futex_key key2 = FUTEX_KEY_INIT;
struct futex_q q = futex_q_init;
int res, ret;
@@ -3302,55 +3302,20 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
/* Queue the futex_q, drop the hb lock, wait for wakeup. */
futex_wait_queue_me(hb, &q, to);

- /*
- * On RT we must avoid races with requeue and trying to block
- * on two mutexes (hb->lock and uaddr2's rtmutex) by
- * serializing access to pi_blocked_on with pi_lock.
- */
- raw_spin_lock_irq(&current->pi_lock);
- if (current->pi_blocked_on) {
- /*
- * We have been requeued or are in the process of
- * being requeued.
- */
- raw_spin_unlock_irq(&current->pi_lock);
- } else {
- /*
- * Setting pi_blocked_on to PI_WAKEUP_INPROGRESS
- * prevents a concurrent requeue from moving us to the
- * uaddr2 rtmutex. After that we can safely acquire
- * (and possibly block on) hb->lock.
- */
- current->pi_blocked_on = PI_WAKEUP_INPROGRESS;
- raw_spin_unlock_irq(&current->pi_lock);
-
- spin_lock(&hb->lock);
-
- /*
- * Clean up pi_blocked_on. We might leak it otherwise
- * when we succeeded with the hb->lock in the fast
- * path.
- */
- raw_spin_lock_irq(&current->pi_lock);
- current->pi_blocked_on = NULL;
- raw_spin_unlock_irq(&current->pi_lock);
-
- ret = handle_early_requeue_pi_wakeup(hb, &q, &key2, to);
- spin_unlock(&hb->lock);
- if (ret)
- goto out_put_keys;
- }
+ raw_spin_lock(&hb->lock);
+ ret = handle_early_requeue_pi_wakeup(hb, &q, &key2, to);
+ raw_spin_unlock(&hb->lock);
+ if (ret)
+ goto out_put_keys;

/*
- * In order to be here, we have either been requeued, are in
- * the process of being requeued, or requeue successfully
- * acquired uaddr2 on our behalf. If pi_blocked_on was
- * non-null above, we may be racing with a requeue. Do not
- * rely on q->lock_ptr to be hb2->lock until after blocking on
- * hb->lock or hb2->lock. The futex_requeue dropped our key1
- * reference and incremented our key2 reference count.
+ * In order for us to be here, we know our q.key == key2, and since
+ * we took the hb->lock above, we also know that futex_requeue() has
+ * completed and we no longer have to concern ourselves with a wakeup
+ * race with the atomic proxy lock acquisition by the requeue code. The
+ * futex_requeue dropped our key1 reference and incremented our key2
+ * reference count.
*/
- hb2 = hash_futex(&key2);

/* Check if the requeue code acquired the second futex for us. */
if (!q.rt_waiter) {
@@ -3359,8 +3324,9 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
* did a lock-steal - fix up the PI-state in that case.
*/
if (q.pi_state && (q.pi_state->owner != current)) {
- spin_lock(&hb2->lock);
- BUG_ON(&hb2->lock != q.lock_ptr);
+ struct futex_pi_state *ps_free;
+
+ raw_spin_lock(q.lock_ptr);
ret = fixup_pi_state_owner(uaddr2, &q, current);
if (ret && rt_mutex_owner(&q.pi_state->pi_mutex) == current) {
pi_state = q.pi_state;
@@ -3370,8 +3336,9 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
* Drop the reference to the pi state which
* the requeue_pi() code acquired for us.
*/
- put_pi_state(q.pi_state);
- spin_unlock(&hb2->lock);
+ ps_free = __put_pi_state(q.pi_state);
+ raw_spin_unlock(q.lock_ptr);
+ kfree(ps_free);
}
} else {
struct rt_mutex *pi_mutex;
@@ -3385,8 +3352,7 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
pi_mutex = &q.pi_state->pi_mutex;
ret = rt_mutex_wait_proxy_lock(pi_mutex, to, &rt_waiter);

- spin_lock(&hb2->lock);
- BUG_ON(&hb2->lock != q.lock_ptr);
+ raw_spin_lock(q.lock_ptr);
if (ret && !rt_mutex_cleanup_proxy_lock(pi_mutex, &rt_waiter))
ret = 0;

@@ -4011,7 +3977,7 @@ static int __init futex_init(void)
for (i = 0; i < futex_hashsize; i++) {
atomic_set(&futex_queues[i].waiters, 0);
plist_head_init(&futex_queues[i].chain);
- spin_lock_init(&futex_queues[i].lock);
+ raw_spin_lock_init(&futex_queues[i].lock);
}

return 0;
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index 9c1ae2f0c1d27..62f14671aeca2 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -142,12 +142,6 @@ static void fixup_rt_mutex_waiters(struct rt_mutex *lock)
WRITE_ONCE(*p, owner & ~RT_MUTEX_HAS_WAITERS);
}

-static int rt_mutex_real_waiter(struct rt_mutex_waiter *waiter)
-{
- return waiter && waiter != PI_WAKEUP_INPROGRESS &&
- waiter != PI_REQUEUE_INPROGRESS;
-}
-
/*
* We can speed up the acquire/release, if there's no debugging state to be
* set up.
@@ -421,8 +415,7 @@ int max_lock_depth = 1024;

static inline struct rt_mutex *task_blocked_on_lock(struct task_struct *p)
{
- return rt_mutex_real_waiter(p->pi_blocked_on) ?
- p->pi_blocked_on->lock : NULL;
+ return p->pi_blocked_on ? p->pi_blocked_on->lock : NULL;
}

/*
@@ -558,7 +551,7 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task,
* reached or the state of the chain has changed while we
* dropped the locks.
*/
- if (!rt_mutex_real_waiter(waiter))
+ if (!waiter)
goto out_unlock_pi;

/*
@@ -1328,22 +1321,6 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
return -EDEADLK;

raw_spin_lock(&task->pi_lock);
- /*
- * In the case of futex requeue PI, this will be a proxy
- * lock. The task will wake unaware that it is enqueueed on
- * this lock. Avoid blocking on two locks and corrupting
- * pi_blocked_on via the PI_WAKEUP_INPROGRESS
- * flag. futex_wait_requeue_pi() sets this when it wakes up
- * before requeue (due to a signal or timeout). Do not enqueue
- * the task if PI_WAKEUP_INPROGRESS is set.
- */
- if (task != current && task->pi_blocked_on == PI_WAKEUP_INPROGRESS) {
- raw_spin_unlock(&task->pi_lock);
- return -EAGAIN;
- }
-
- BUG_ON(rt_mutex_real_waiter(task->pi_blocked_on));
-
waiter->task = task;
waiter->lock = lock;
waiter->prio = task->prio;
@@ -1367,7 +1344,7 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
rt_mutex_enqueue_pi(owner, waiter);

rt_mutex_adjust_prio(owner);
- if (rt_mutex_real_waiter(owner->pi_blocked_on))
+ if (owner->pi_blocked_on)
chain_walk = 1;
} else if (rt_mutex_cond_detect_deadlock(waiter, chwalk)) {
chain_walk = 1;
@@ -1467,7 +1444,7 @@ static void remove_waiter(struct rt_mutex *lock,
{
bool is_top_waiter = (waiter == rt_mutex_top_waiter(lock));
struct task_struct *owner = rt_mutex_owner(lock);
- struct rt_mutex *next_lock = NULL;
+ struct rt_mutex *next_lock;

lockdep_assert_held(&lock->wait_lock);

@@ -1493,8 +1470,7 @@ static void remove_waiter(struct rt_mutex *lock,
rt_mutex_adjust_prio(owner);

/* Store the lock on which owner is blocked or NULL */
- if (rt_mutex_real_waiter(owner->pi_blocked_on))
- next_lock = task_blocked_on_lock(owner);
+ next_lock = task_blocked_on_lock(owner);

raw_spin_unlock(&owner->pi_lock);

@@ -1530,8 +1506,7 @@ void rt_mutex_adjust_pi(struct task_struct *task)
raw_spin_lock_irqsave(&task->pi_lock, flags);

waiter = task->pi_blocked_on;
- if (!rt_mutex_real_waiter(waiter) ||
- rt_mutex_waiter_equal(waiter, task_to_waiter(task))) {
+ if (!waiter || rt_mutex_waiter_equal(waiter, task_to_waiter(task))) {
raw_spin_unlock_irqrestore(&task->pi_lock, flags);
return;
}
@@ -2350,34 +2325,6 @@ int __rt_mutex_start_proxy_lock(struct rt_mutex *lock,
if (try_to_take_rt_mutex(lock, task, NULL))
return 1;

-#ifdef CONFIG_PREEMPT_RT_FULL
- /*
- * In PREEMPT_RT there's an added race.
- * If the task, that we are about to requeue, times out,
- * it can set the PI_WAKEUP_INPROGRESS. This tells the requeue
- * to skip this task. But right after the task sets
- * its pi_blocked_on to PI_WAKEUP_INPROGRESS it can then
- * block on the spin_lock(&hb->lock), which in RT is an rtmutex.
- * This will replace the PI_WAKEUP_INPROGRESS with the actual
- * lock that it blocks on. We *must not* place this task
- * on this proxy lock in that case.
- *
- * To prevent this race, we first take the task's pi_lock
- * and check if it has updated its pi_blocked_on. If it has,
- * we assume that it woke up and we return -EAGAIN.
- * Otherwise, we set the task's pi_blocked_on to
- * PI_REQUEUE_INPROGRESS, so that if the task is waking up
- * it will know that we are in the process of requeuing it.
- */
- raw_spin_lock(&task->pi_lock);
- if (task->pi_blocked_on) {
- raw_spin_unlock(&task->pi_lock);
- return -EAGAIN;
- }
- task->pi_blocked_on = PI_REQUEUE_INPROGRESS;
- raw_spin_unlock(&task->pi_lock);
-#endif
-
/* We enforce deadlock detection for futexes */
ret = task_blocks_on_rt_mutex(lock, waiter, task,
RT_MUTEX_FULL_CHAINWALK);
diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h
index 546aaf058b9ec..758dc43872e5b 100644
--- a/kernel/locking/rtmutex_common.h
+++ b/kernel/locking/rtmutex_common.h
@@ -132,9 +132,6 @@ enum rtmutex_chainwalk {
/*
* PI-futex support (proxy locking functions, etc.):
*/
-#define PI_WAKEUP_INPROGRESS ((struct rt_mutex_waiter *) 1)
-#define PI_REQUEUE_INPROGRESS ((struct rt_mutex_waiter *) 2)
-
extern struct task_struct *rt_mutex_next_owner(struct rt_mutex *lock);
extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
struct task_struct *proxy_owner);
diff --git a/kernel/sched/completion.c b/kernel/sched/completion.c
index 49c14137988ea..755a580849781 100644
--- a/kernel/sched/completion.c
+++ b/kernel/sched/completion.c
@@ -72,12 +72,12 @@ do_wait_for_common(struct completion *x,
if (!x->done) {
DECLARE_SWAITQUEUE(wait);

+ __prepare_to_swait(&x->wait, &wait);
do {
if (signal_pending_state(state, current)) {
timeout = -ERESTARTSYS;
break;
}
- __prepare_to_swait(&x->wait, &wait);
__set_current_state(state);
raw_spin_unlock_irq(&x->wait.lock);
timeout = action(timeout);
diff --git a/kernel/sched/swait.c b/kernel/sched/swait.c
index c58068d2ee06c..e2c3d2691edf1 100644
--- a/kernel/sched/swait.c
+++ b/kernel/sched/swait.c
@@ -28,7 +28,8 @@ void swake_up_locked(struct swait_queue_head *q)

curr = list_first_entry(&q->task_list, typeof(*curr), task_list);
wake_up_process(curr->task);
- list_del_init(&curr->task_list);
+ if (curr->remove)
+ list_del_init(&curr->task_list);
}
EXPORT_SYMBOL(swake_up_locked);

@@ -77,7 +78,8 @@ void swake_up_all(struct swait_queue_head *q)
curr = list_first_entry(&tmp, typeof(*curr), task_list);

wake_up_state(curr->task, TASK_NORMAL);
- list_del_init(&curr->task_list);
+ if (curr->remove)
+ list_del_init(&curr->task_list);

if (list_empty(&tmp))
break;
diff --git a/localversion-rt b/localversion-rt
index 9f7d0bdbffb18..08b3e75841adc 100644
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt13
+-rt14
diff --git a/mm/zswap.c b/mm/zswap.c
index a4e4d36ec0858..fd5d2d5c9ae94 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -27,6 +27,7 @@
#include <linux/highmem.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
+#include <linux/locallock.h>
#include <linux/types.h>
#include <linux/atomic.h>
#include <linux/frontswap.h>
@@ -990,6 +991,8 @@ static void zswap_fill_page(void *ptr, unsigned long value)
memset_l(page, value, PAGE_SIZE / sizeof(unsigned long));
}

+/* protect zswap_dstmem from concurrency */
+static DEFINE_LOCAL_IRQ_LOCK(zswap_dstmem_lock);
/*********************************
* frontswap hooks
**********************************/
@@ -1066,12 +1069,11 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
}

/* compress */
- dst = get_cpu_var(zswap_dstmem);
- tfm = *get_cpu_ptr(entry->pool->tfm);
+ dst = get_locked_var(zswap_dstmem_lock, zswap_dstmem);
+ tfm = *this_cpu_ptr(entry->pool->tfm);
src = kmap_atomic(page);
ret = crypto_comp_compress(tfm, src, PAGE_SIZE, dst, &dlen);
kunmap_atomic(src);
- put_cpu_ptr(entry->pool->tfm);
if (ret) {
ret = -EINVAL;
goto put_dstmem;
@@ -1094,7 +1096,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
memcpy(buf, &zhdr, hlen);
memcpy(buf + hlen, dst, dlen);
zpool_unmap_handle(entry->pool->zpool, handle);
- put_cpu_var(zswap_dstmem);
+ put_locked_var(zswap_dstmem_lock, zswap_dstmem);

/* populate entry */
entry->offset = offset;
@@ -1122,7 +1124,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
return 0;

put_dstmem:
- put_cpu_var(zswap_dstmem);
+ put_locked_var(zswap_dstmem_lock, zswap_dstmem);
zswap_pool_put(entry->pool);
freepage:
zswap_entry_cache_free(entry);