Merge tag 'mm-nonmm-stable-2025-05-31-15-28' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mmHEADmaster

Pull non-MM updates from Andrew Morton:

 - "hung_task: extend blocking task stacktrace dump to semaphore" from
   Lance Yang enhances the hung task detector.

   The detector presently dumps the blocking tasks's stack when it is
   blocked on a mutex. Lance's series extends this to semaphores

 - "nilfs2: improve sanity checks in dirty state propagation" from
   Wentao Liang addresses a couple of minor flaws in nilfs2

 - "scripts/gdb: Fixes related to lx_per_cpu()" from Illia Ostapyshyn
   fixes a couple of issues in the gdb scripts

 - "Support kdump with LUKS encryption by reusing LUKS volume keys" from
   Coiby Xu addresses a usability problem with kdump.

   When the dump device is LUKS-encrypted, the kdump kernel may not have
   the keys to the encrypted filesystem. A full writeup of this is in
   the series [0/N] cover letter

 - "sysfs: add counters for lockups and stalls" from Max Kellermann adds
   /sys/kernel/hardlockup_count and /sys/kernel/hardlockup_count and
   /sys/kernel/rcu_stall_count

 - "fork: Page operation cleanups in the fork code" from Pasha Tatashin
   implements a number of code cleanups in fork.c

 - "scripts/gdb/symbols: determine KASLR offset on s390 during early
   boot" from Ilya Leoshkevich fixes some s390 issues in the gdb
   scripts

* tag 'mm-nonmm-stable-2025-05-31-15-28' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (67 commits)
  llist: make llist_add_batch() a static inline
  delayacct: remove redundant code and adjust indentation
  squashfs: add optional full compressed block caching
  crash_dump, nvme: select CONFIGFS_FS as built-in
  scripts/gdb/symbols: determine KASLR offset on s390 during early boot
  scripts/gdb/symbols: factor out pagination_off()
  scripts/gdb/symbols: factor out get_vmlinux()
  kernel/panic.c: format kernel-doc comments
  mailmap: update and consolidate Casey Connolly's name and email
  nilfs2: remove wbc->for_reclaim handling
  fork: define a local GFP_VMAP_STACK
  fork: check charging success before zeroing stack
  fork: clean-up naming of vm_stack/vm_struct variables in vmap stacks code
  fork: clean-up ifdef logic around stack allocation
  kernel/rcu/tree_stall: add /sys/kernel/rcu_stall_count
  kernel/watchdog: add /sys/kernel/{hard,soft}lockup_count
  x86/crash: make the page that stores the dm crypt keys inaccessible
  x86/crash: pass dm crypt keys to kdump kernel
  Revert "x86/mm: Remove unused __set_memory_prot()"
  crash_dump: retrieve dm crypt keys in kdump kernel
  ...

2 files changed, 54 insertions, 8 deletions

diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
index 555e2b3a665a..61fa97da7989 100644
--- a/kernel/locking/mutex.c
+++ b/kernel/locking/mutex.c
@@ -29,6 +29,7 @@
 #include <linux/interrupt.h>
 #include <linux/debug_locks.h>
 #include <linux/osq_lock.h>
+#include <linux/hung_task.h>
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/lock.h>
@@ -191,7 +192,7 @@ __mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter,
 		   struct list_head *list)
 {
 #ifdef CONFIG_DETECT_HUNG_TASK_BLOCKER
-	WRITE_ONCE(current->blocker_mutex, lock);
+	hung_task_set_blocker(lock, BLOCKER_TYPE_MUTEX);
 #endif
 	debug_mutex_add_waiter(lock, waiter, current);
 
@@ -209,7 +210,7 @@ __mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter)
 
 	debug_mutex_remove_waiter(lock, waiter, current);
 #ifdef CONFIG_DETECT_HUNG_TASK_BLOCKER
-	WRITE_ONCE(current->blocker_mutex, NULL);
+	hung_task_clear_blocker();
 #endif
 }
 
diff --git a/kernel/locking/semaphore.c b/kernel/locking/semaphore.c
index de9117c0e671..3ef032e22f7e 100644
--- a/kernel/locking/semaphore.c
+++ b/kernel/locking/semaphore.c
@@ -34,6 +34,7 @@
 #include <linux/spinlock.h>
 #include <linux/ftrace.h>
 #include <trace/events/lock.h>
+#include <linux/hung_task.h>
 
 static noinline void __down(struct semaphore *sem);
 static noinline int __down_interruptible(struct semaphore *sem);
@@ -41,6 +42,41 @@ static noinline int __down_killable(struct semaphore *sem);
 static noinline int __down_timeout(struct semaphore *sem, long timeout);
 static noinline void __up(struct semaphore *sem, struct wake_q_head *wake_q);
 
+#ifdef CONFIG_DETECT_HUNG_TASK_BLOCKER
+static inline void hung_task_sem_set_holder(struct semaphore *sem)
+{
+	WRITE_ONCE((sem)->last_holder, (unsigned long)current);
+}
+
+static inline void hung_task_sem_clear_if_holder(struct semaphore *sem)
+{
+	if (READ_ONCE((sem)->last_holder) == (unsigned long)current)
+		WRITE_ONCE((sem)->last_holder, 0UL);
+}
+
+unsigned long sem_last_holder(struct semaphore *sem)
+{
+	return READ_ONCE(sem->last_holder);
+}
+#else
+static inline void hung_task_sem_set_holder(struct semaphore *sem)
+{
+}
+static inline void hung_task_sem_clear_if_holder(struct semaphore *sem)
+{
+}
+unsigned long sem_last_holder(struct semaphore *sem)
+{
+	return 0UL;
+}
+#endif
+
+static inline void __sem_acquire(struct semaphore *sem)
+{
+	sem->count--;
+	hung_task_sem_set_holder(sem);
+}
+
 /**
  * down - acquire the semaphore
  * @sem: the semaphore to be acquired
@@ -59,7 +95,7 @@ void __sched down(struct semaphore *sem)
 	might_sleep();
 	raw_spin_lock_irqsave(&sem->lock, flags);
 	if (likely(sem->count > 0))
-		sem->count--;
+		__sem_acquire(sem);
 	else
 		__down(sem);
 	raw_spin_unlock_irqrestore(&sem->lock, flags);
@@ -83,7 +119,7 @@ int __sched down_interruptible(struct semaphore *sem)
 	might_sleep();
 	raw_spin_lock_irqsave(&sem->lock, flags);
 	if (likely(sem->count > 0))
-		sem->count--;
+		__sem_acquire(sem);
 	else
 		result = __down_interruptible(sem);
 	raw_spin_unlock_irqrestore(&sem->lock, flags);
@@ -110,7 +146,7 @@ int __sched down_killable(struct semaphore *sem)
 	might_sleep();
 	raw_spin_lock_irqsave(&sem->lock, flags);
 	if (likely(sem->count > 0))
-		sem->count--;
+		__sem_acquire(sem);
 	else
 		result = __down_killable(sem);
 	raw_spin_unlock_irqrestore(&sem->lock, flags);
@@ -140,7 +176,7 @@ int __sched down_trylock(struct semaphore *sem)
 	raw_spin_lock_irqsave(&sem->lock, flags);
 	count = sem->count - 1;
 	if (likely(count >= 0))
-		sem->count = count;
+		__sem_acquire(sem);
 	raw_spin_unlock_irqrestore(&sem->lock, flags);
 
 	return (count < 0);
@@ -165,7 +201,7 @@ int __sched down_timeout(struct semaphore *sem, long timeout)
 	might_sleep();
 	raw_spin_lock_irqsave(&sem->lock, flags);
 	if (likely(sem->count > 0))
-		sem->count--;
+		__sem_acquire(sem);
 	else
 		result = __down_timeout(sem, timeout);
 	raw_spin_unlock_irqrestore(&sem->lock, flags);
@@ -187,6 +223,9 @@ void __sched up(struct semaphore *sem)
 	DEFINE_WAKE_Q(wake_q);
 
 	raw_spin_lock_irqsave(&sem->lock, flags);
+
+	hung_task_sem_clear_if_holder(sem);
+
 	if (likely(list_empty(&sem->wait_list)))
 		sem->count++;
 	else
@@ -228,8 +267,10 @@ static inline int __sched ___down_common(struct semaphore *sem, long state,
 		raw_spin_unlock_irq(&sem->lock);
 		timeout = schedule_timeout(timeout);
 		raw_spin_lock_irq(&sem->lock);
-		if (waiter.up)
+		if (waiter.up) {
+			hung_task_sem_set_holder(sem);
 			return 0;
+		}
 	}
 
  timed_out:
@@ -246,10 +287,14 @@ static inline int __sched __down_common(struct semaphore *sem, long state,
 {
 	int ret;
 
+	hung_task_set_blocker(sem, BLOCKER_TYPE_SEM);
+
 	trace_contention_begin(sem, 0);
 	ret = ___down_common(sem, state, timeout);
 	trace_contention_end(sem, ret);
 
+	hung_task_clear_blocker();
+
 	return ret;
 }