Commit b53440f8 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'locking-core-2025-12-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull locking updates from Ingo Molnar:
 "Mutexes:

   - Redo __mutex_init() to reduce generated code size (Sebastian
     Andrzej Siewior)

  Seqlocks:

   - Introduce scoped_seqlock_read() (Peter Zijlstra)

   - Change thread_group_cputime() to use scoped_seqlock_read() (Oleg
     Nesterov)

   - Change do_task_stat() to use scoped_seqlock_read() (Oleg Nesterov)

   - Change do_io_accounting() to use scoped_seqlock_read() (Oleg
     Nesterov)

   - Fix the incorrect documentation of read_seqbegin_or_lock() /
     need_seqretry() (Oleg Nesterov)

   - Allow KASAN to fail optimizing (Peter Zijlstra)

  Local lock updates:

   - Fix all kernel-doc warnings (Randy Dunlap)

   - Add the <linux/local_lock*.h> headers to MAINTAINERS (Sebastian
     Andrzej Siewior)

   - Reduce the risk of shadowing via s/l/__l/ and s/tl/__tl/ (Vincent
     Mailhol)

  Lock debugging:

   - spinlock/debug: Fix data-race in do_raw_write_lock (Alexander
     Sverdlin)

  Atomic primitives infrastructure:

   - atomic: Skip alignment check for try_cmpxchg() old arg (Arnd
     Bergmann)

  Rust runtime integration:

   - sync: atomic: Enable generated Atomic<T> usage (Boqun Feng)

   - sync: atomic: Implement Debug for Atomic<Debug> (Boqun Feng)

   - debugfs: Remove Rust native atomics and replace them with Linux
     versions (Boqun Feng)

   - debugfs: Implement Reader for Mutex<T> only when T is Unpin (Boqun
     Feng)

   - lock: guard: Add T: Unpin bound to DerefMut (Daniel Almeida)

   - lock: Pin the inner data (Daniel Almeida)

   - lock: Add a Pin<&mut T> accessor (Daniel Almeida)"

* tag 'locking-core-2025-12-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/local_lock: Fix all kernel-doc warnings
  locking/local_lock: s/l/__l/ and s/tl/__tl/ to reduce the risk of shadowing
  locking/local_lock: Add the <linux/local_lock*.h> headers to MAINTAINERS
  locking/mutex: Redo __mutex_init() to reduce generated code size
  rust: debugfs: Replace the usage of Rust native atomics
  rust: sync: atomic: Implement Debug for Atomic<Debug>
  rust: sync: atomic: Make Atomic*Ops pub(crate)
  seqlock: Allow KASAN to fail optimizing
  rust: debugfs: Implement Reader for Mutex<T> only when T is Unpin
  seqlock: Change do_io_accounting() to use scoped_seqlock_read()
  seqlock: Change do_task_stat() to use scoped_seqlock_read()
  seqlock: Change thread_group_cputime() to use scoped_seqlock_read()
  seqlock: Introduce scoped_seqlock_read()
  documentation: seqlock: fix the wrong documentation of read_seqbegin_or_lock/need_seqretry
  atomic: Skip alignment check for try_cmpxchg() old arg
  rust: lock: Add a Pin<&mut T> accessor
  rust: lock: Pin the inner data
  rust: lock: guard: Add T: Unpin bound to DerefMut
  locking/spinlock/debug: Fix data-race in do_raw_write_lock
parents 1b5dd298 43decb6b

Documentation/locking/seqlock.rst

+5 −4
Original line number Diff line number Diff line
@@ -220,13 +220,14 @@ Read path, three categories: 
   according to a passed marker. This is used to avoid lockless readers

   starvation (too much retry loops) in case of a sharp spike in write

   activity. First, a lockless read is tried (even marker passed). If

   that trial fails (odd sequence counter is returned, which is used as

   the next iteration marker), the lockless read is transformed to a

   full locking read and no retry loop is necessary::

   that trial fails (sequence counter doesn't match), make the marker

   odd for the next iteration, the lockless read is transformed to a

   full locking read and no retry loop is necessary, for example::



	/* marker; even initialization */

	int seq = 0;

	int seq = 1;

	do {

		seq++; /* 2 on the 1st/lockless path, otherwise odd */

		read_seqbegin_or_lock(&foo_seqlock, &seq);



		/* ... [[read-side critical section]] ... */

MAINTAINERS

+1 −0
Original line number Diff line number Diff line
@@ -14536,6 +14536,7 @@ S: Maintained 
T:	git git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git locking/core

F:	Documentation/locking/

F:	arch/*/include/asm/spinlock*.h

F:	include/linux/local_lock*.h

F:	include/linux/lockdep*.h

F:	include/linux/mutex*.h

F:	include/linux/rwlock*.h

fs/proc/array.c

+2 −7
Original line number Diff line number Diff line
@@ -481,7 +481,6 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns, 
	unsigned long flags;

	int exit_code = task->exit_code;

	struct signal_struct *sig = task->signal;

	unsigned int seq = 1;



	state = *get_task_state(task);

	vsize = eip = esp = 0;
@@ -538,10 +537,7 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns, 
	if (permitted && (!whole || num_threads < 2))

		wchan = !task_is_running(task);



	do {

		seq++; /* 2 on the 1st/lockless path, otherwise odd */

		flags = read_seqbegin_or_lock_irqsave(&sig->stats_lock, &seq);



	scoped_seqlock_read (&sig->stats_lock, ss_lock_irqsave) {

		cmin_flt = sig->cmin_flt;

		cmaj_flt = sig->cmaj_flt;

		cutime = sig->cutime;
@@ -563,8 +559,7 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns, 
			}

			rcu_read_unlock();

		}

	} while (need_seqretry(&sig->stats_lock, seq));

	done_seqretry_irqrestore(&sig->stats_lock, seq, flags);

	}



	if (whole) {

		thread_group_cputime_adjusted(task, &utime, &stime);

fs/proc/base.c

+3 −10
Original line number Diff line number Diff line
@@ -3043,21 +3043,14 @@ static int do_io_accounting(struct task_struct *task, struct seq_file *m, int wh 
	if (whole) {

		struct signal_struct *sig = task->signal;

		struct task_struct *t;

		unsigned int seq = 1;

		unsigned long flags;



		rcu_read_lock();

		do {

			seq++; /* 2 on the 1st/lockless path, otherwise odd */

			flags = read_seqbegin_or_lock_irqsave(&sig->stats_lock, &seq);



		guard(rcu)();

		scoped_seqlock_read (&sig->stats_lock, ss_lock_irqsave) {

			acct = sig->ioac;

			__for_each_thread(sig, t)

				task_io_accounting_add(&acct, &t->ioac);



		} while (need_seqretry(&sig->stats_lock, seq));

		done_seqretry_irqrestore(&sig->stats_lock, seq, flags);

		rcu_read_unlock();

		}

	} else {

		acct = task->ioac;

	}

include/linux/atomic/atomic-instrumented.h

+13 −13
Original line number Diff line number Diff line
@@ -1276,7 +1276,7 @@ atomic_try_cmpxchg(atomic_t *v, int *old, int new) 
{

	kcsan_mb();

	instrument_atomic_read_write(v, sizeof(*v));

	instrument_atomic_read_write(old, sizeof(*old));

	instrument_read_write(old, sizeof(*old));

	return raw_atomic_try_cmpxchg(v, old, new);

}
@@ -1298,7 +1298,7 @@ static __always_inline bool 
atomic_try_cmpxchg_acquire(atomic_t *v, int *old, int new)

{

	instrument_atomic_read_write(v, sizeof(*v));

	instrument_atomic_read_write(old, sizeof(*old));

	instrument_read_write(old, sizeof(*old));

	return raw_atomic_try_cmpxchg_acquire(v, old, new);

}
@@ -1321,7 +1321,7 @@ atomic_try_cmpxchg_release(atomic_t *v, int *old, int new) 
{

	kcsan_release();

	instrument_atomic_read_write(v, sizeof(*v));

	instrument_atomic_read_write(old, sizeof(*old));

	instrument_read_write(old, sizeof(*old));

	return raw_atomic_try_cmpxchg_release(v, old, new);

}
@@ -1343,7 +1343,7 @@ static __always_inline bool 
atomic_try_cmpxchg_relaxed(atomic_t *v, int *old, int new)

{

	instrument_atomic_read_write(v, sizeof(*v));

	instrument_atomic_read_write(old, sizeof(*old));

	instrument_read_write(old, sizeof(*old));

	return raw_atomic_try_cmpxchg_relaxed(v, old, new);

}
@@ -2854,7 +2854,7 @@ atomic64_try_cmpxchg(atomic64_t *v, s64 *old, s64 new) 
{

	kcsan_mb();

	instrument_atomic_read_write(v, sizeof(*v));

	instrument_atomic_read_write(old, sizeof(*old));

	instrument_read_write(old, sizeof(*old));

	return raw_atomic64_try_cmpxchg(v, old, new);

}
@@ -2876,7 +2876,7 @@ static __always_inline bool 
atomic64_try_cmpxchg_acquire(atomic64_t *v, s64 *old, s64 new)

{

	instrument_atomic_read_write(v, sizeof(*v));

	instrument_atomic_read_write(old, sizeof(*old));

	instrument_read_write(old, sizeof(*old));

	return raw_atomic64_try_cmpxchg_acquire(v, old, new);

}
@@ -2899,7 +2899,7 @@ atomic64_try_cmpxchg_release(atomic64_t *v, s64 *old, s64 new) 
{

	kcsan_release();

	instrument_atomic_read_write(v, sizeof(*v));

	instrument_atomic_read_write(old, sizeof(*old));

	instrument_read_write(old, sizeof(*old));

	return raw_atomic64_try_cmpxchg_release(v, old, new);

}
@@ -2921,7 +2921,7 @@ static __always_inline bool 
atomic64_try_cmpxchg_relaxed(atomic64_t *v, s64 *old, s64 new)

{

	instrument_atomic_read_write(v, sizeof(*v));

	instrument_atomic_read_write(old, sizeof(*old));

	instrument_read_write(old, sizeof(*old));

	return raw_atomic64_try_cmpxchg_relaxed(v, old, new);

}
@@ -4432,7 +4432,7 @@ atomic_long_try_cmpxchg(atomic_long_t *v, long *old, long new) 
{

	kcsan_mb();

	instrument_atomic_read_write(v, sizeof(*v));

	instrument_atomic_read_write(old, sizeof(*old));

	instrument_read_write(old, sizeof(*old));

	return raw_atomic_long_try_cmpxchg(v, old, new);

}
@@ -4454,7 +4454,7 @@ static __always_inline bool 
atomic_long_try_cmpxchg_acquire(atomic_long_t *v, long *old, long new)

{

	instrument_atomic_read_write(v, sizeof(*v));

	instrument_atomic_read_write(old, sizeof(*old));

	instrument_read_write(old, sizeof(*old));

	return raw_atomic_long_try_cmpxchg_acquire(v, old, new);

}
@@ -4477,7 +4477,7 @@ atomic_long_try_cmpxchg_release(atomic_long_t *v, long *old, long new) 
{

	kcsan_release();

	instrument_atomic_read_write(v, sizeof(*v));

	instrument_atomic_read_write(old, sizeof(*old));

	instrument_read_write(old, sizeof(*old));

	return raw_atomic_long_try_cmpxchg_release(v, old, new);

}
@@ -4499,7 +4499,7 @@ static __always_inline bool 
atomic_long_try_cmpxchg_relaxed(atomic_long_t *v, long *old, long new)

{

	instrument_atomic_read_write(v, sizeof(*v));

	instrument_atomic_read_write(old, sizeof(*old));

	instrument_read_write(old, sizeof(*old));

	return raw_atomic_long_try_cmpxchg_relaxed(v, old, new);

}
@@ -5050,4 +5050,4 @@ atomic_long_dec_if_positive(atomic_long_t *v) 




#endif /* _LINUX_ATOMIC_INSTRUMENTED_H */

// 8829b337928e9508259079d32581775ececd415b
 
// f618ac667f868941a84ce0ab2242f1786e049ed4