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locking fixes

GIT PULL Merged Ingo Molnar 2 participants 2 messages Mar 21, 2021

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Linus,

Please pull the latest locking/urgent git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git locking-urgent-2021-03-21

# HEAD: 38c93587375053c5b9ef093f4a5ea754538cba32 static_call: Fix static_call_update() sanity check

Locking fixes:

- Get static calls & modules right. Hopefully.
- WW mutex fixes

Thanks,

Ingo

------------------>
Peter Zijlstra (3):
static_call: Fix static_call_set_init()
static_call: Align static_call_is_init() patching condition
static_call: Fix static_call_update() sanity check

Waiman Long (2):
locking/ww_mutex: Simplify use_ww_ctx & ww_ctx handling locking/ww_mutex: Fix acquire/release imbalance in ww_acquire_init()/ww_acquire_fini()

 include/linux/ww_mutex.h |  5 +++--
 kernel/jump_label.c      |  8 ++++++++
 kernel/locking/mutex.c   | 25 ++++++++++++++-----------
 kernel/static_call.c     | 42 ++++++++++++++++++++++++------------------
 4 files changed, 49 insertions(+), 31 deletions(-)
include/linux/ww_mutex.h +3 -2
index 850424e5d030..6ecf2a0220db 100644
@@ -173,9 +173,10 @@ static inline void ww_acquire_done(struct ww_acquire_ctx *ctx)
  */
 static inline void ww_acquire_fini(struct ww_acquire_ctx *ctx)
 {
-#ifdef CONFIG_DEBUG_MUTEXES
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
 	mutex_release(&ctx->dep_map, _THIS_IP_);
-
+#endif
+#ifdef CONFIG_DEBUG_MUTEXES
 	DEBUG_LOCKS_WARN_ON(ctx->acquired);
 	if (!IS_ENABLED(CONFIG_PROVE_LOCKING))
 		/*
kernel/jump_label.c +8 -0
index c6a39d662935..ba39fbb1f8e7 100644
@@ -407,6 +407,14 @@ static bool jump_label_can_update(struct jump_entry *entry, bool init)
 		return false;
 
 	if (!kernel_text_address(jump_entry_code(entry))) {
+		/*
+		 * This skips patching built-in __exit, which
+		 * is part of init_section_contains() but is
+		 * not part of kernel_text_address().
+		 *
+		 * Skipping built-in __exit is fine since it
+		 * will never be executed.
+		 */
 		WARN_ONCE(!jump_entry_is_init(entry),
 			  "can't patch jump_label at %pS",
 			  (void *)jump_entry_code(entry));
kernel/locking/mutex.c +14 -11
index adb935090768..622ebdfcd083 100644
@@ -626,7 +626,7 @@ static inline int mutex_can_spin_on_owner(struct mutex *lock)
  */
 static __always_inline bool
 mutex_optimistic_spin(struct mutex *lock, struct ww_acquire_ctx *ww_ctx,
-		      const bool use_ww_ctx, struct mutex_waiter *waiter)
+		      struct mutex_waiter *waiter)
 {
 	if (!waiter) {
 		/*
@@ -702,7 +702,7 @@ mutex_optimistic_spin(struct mutex *lock, struct ww_acquire_ctx *ww_ctx,
 #else
 static __always_inline bool
 mutex_optimistic_spin(struct mutex *lock, struct ww_acquire_ctx *ww_ctx,
-		      const bool use_ww_ctx, struct mutex_waiter *waiter)
+		      struct mutex_waiter *waiter)
 {
 	return false;
 }
@@ -922,6 +922,9 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
 	struct ww_mutex *ww;
 	int ret;
 
+	if (!use_ww_ctx)
+		ww_ctx = NULL;
+
 	might_sleep();
 
 #ifdef CONFIG_DEBUG_MUTEXES
@@ -929,7 +932,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
 #endif
 
 	ww = container_of(lock, struct ww_mutex, base);
-	if (use_ww_ctx && ww_ctx) {
+	if (ww_ctx) {
 		if (unlikely(ww_ctx == READ_ONCE(ww->ctx)))
 			return -EALREADY;
 
@@ -946,10 +949,10 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
 	mutex_acquire_nest(&lock->dep_map, subclass, 0, nest_lock, ip);
 
 	if (__mutex_trylock(lock) ||
-	    mutex_optimistic_spin(lock, ww_ctx, use_ww_ctx, NULL)) {
+	    mutex_optimistic_spin(lock, ww_ctx, NULL)) {
 		/* got the lock, yay! */
 		lock_acquired(&lock->dep_map, ip);
-		if (use_ww_ctx && ww_ctx)
+		if (ww_ctx)
 			ww_mutex_set_context_fastpath(ww, ww_ctx);
 		preempt_enable();
 		return 0;
@@ -960,7 +963,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
 	 * After waiting to acquire the wait_lock, try again.
 	 */
 	if (__mutex_trylock(lock)) {
-		if (use_ww_ctx && ww_ctx)
+		if (ww_ctx)
 			__ww_mutex_check_waiters(lock, ww_ctx);
 
 		goto skip_wait;
@@ -1013,7 +1016,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
 			goto err;
 		}
 
-		if (use_ww_ctx && ww_ctx) {
+		if (ww_ctx) {
 			ret = __ww_mutex_check_kill(lock, &waiter, ww_ctx);
 			if (ret)
 				goto err;
@@ -1026,7 +1029,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
 		 * ww_mutex needs to always recheck its position since its waiter
 		 * list is not FIFO ordered.
 		 */
-		if ((use_ww_ctx && ww_ctx) || !first) {
+		if (ww_ctx || !first) {
 			first = __mutex_waiter_is_first(lock, &waiter);
 			if (first)
 				__mutex_set_flag(lock, MUTEX_FLAG_HANDOFF);
@@ -1039,7 +1042,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
 		 * or we must see its unlock and acquire.
 		 */
 		if (__mutex_trylock(lock) ||
-		    (first && mutex_optimistic_spin(lock, ww_ctx, use_ww_ctx, &waiter)))
+		    (first && mutex_optimistic_spin(lock, ww_ctx, &waiter)))
 			break;
 
 		spin_lock(&lock->wait_lock);
@@ -1048,7 +1051,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
 acquired:
 	__set_current_state(TASK_RUNNING);
 
-	if (use_ww_ctx && ww_ctx) {
+	if (ww_ctx) {
 		/*
 		 * Wound-Wait; we stole the lock (!first_waiter), check the
 		 * waiters as anyone might want to wound us.
@@ -1068,7 +1071,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
 	/* got the lock - cleanup and rejoice! */
 	lock_acquired(&lock->dep_map, ip);
 
-	if (use_ww_ctx && ww_ctx)
+	if (ww_ctx)
 		ww_mutex_lock_acquired(ww, ww_ctx);
 
 	spin_unlock(&lock->wait_lock);
kernel/static_call.c +24 -18

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merge bot Merged
#1 lore raw
The pull request you sent on Sun, 21 Mar 2021 11:53:43 +0100:

The pull request you sent on Sun, 21 Mar 2021 11:53:43 +0100:

Quoted 1 line

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git locking-urgent-2021-03-21

has been merged into torvalds/linux.git:
https://git.kernel.org/torvalds/c/5ba33b488a04a13268131b0b4748a7c6f3598693

Thank you!

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