* [PATCH] locking/rwsem: add scoped guard for down_read_killable()
@ 2026-05-29 14:16 Oleg Nesterov
2026-05-29 15:37 ` Marco Elver
2026-05-29 17:21 ` Waiman Long
0 siblings, 2 replies; 3+ messages in thread
From: Oleg Nesterov @ 2026-05-29 14:16 UTC (permalink / raw)
To: Peter Zijlstra, Ingo Molnar, Will Deacon, Boqun Feng, Waiman Long
Cc: Marco Elver, Christian Brauner, linux-kernel
We have lock guards for down_read_trylock/interruptible() but
down_read_killable() is missing.
At least scoped_cond_guard(rwsem_read_kill, signal->exec_update_lock)
can have a lot of users: __pidfd_fget(), mm_access(), find_mm_struct(),
kernel_migrate_pages(), and probably more.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
include/linux/rwsem.h | 3 +++
1 file changed, 3 insertions(+)
diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h
index 6a1a7bae5f81..f0cc72d8f0f2 100644
--- a/include/linux/rwsem.h
+++ b/include/linux/rwsem.h
@@ -259,6 +259,7 @@ extern void up_write(struct rw_semaphore *sem) __releases(sem);
DEFINE_LOCK_GUARD_1(rwsem_read, struct rw_semaphore, down_read(_T->lock), up_read(_T->lock))
DEFINE_LOCK_GUARD_1_COND(rwsem_read, _try, down_read_trylock(_T->lock))
DEFINE_LOCK_GUARD_1_COND(rwsem_read, _intr, down_read_interruptible(_T->lock), _RET == 0)
+DEFINE_LOCK_GUARD_1_COND(rwsem_read, _kill, down_read_killable(_T->lock), _RET == 0)
DECLARE_LOCK_GUARD_1_ATTRS(rwsem_read, __acquires_shared(_T), __releases_shared(*(struct rw_semaphore **)_T))
#define class_rwsem_read_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(rwsem_read, _T)
@@ -266,6 +267,8 @@ DECLARE_LOCK_GUARD_1_ATTRS(rwsem_read_try, __acquires_shared(_T), __releases_sha
#define class_rwsem_read_try_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(rwsem_read_try, _T)
DECLARE_LOCK_GUARD_1_ATTRS(rwsem_read_intr, __acquires_shared(_T), __releases_shared(*(struct rw_semaphore **)_T))
#define class_rwsem_read_intr_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(rwsem_read_intr, _T)
+DECLARE_LOCK_GUARD_1_ATTRS(rwsem_read_kill, __acquires_shared(_T), __releases_shared(*(struct rw_semaphore **)_T))
+#define class_rwsem_read_kill_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(rwsem_read_kill, _T)
DEFINE_LOCK_GUARD_1(rwsem_write, struct rw_semaphore, down_write(_T->lock), up_write(_T->lock))
DEFINE_LOCK_GUARD_1_COND(rwsem_write, _try, down_write_trylock(_T->lock))
--
2.52.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] locking/rwsem: add scoped guard for down_read_killable()
2026-05-29 14:16 [PATCH] locking/rwsem: add scoped guard for down_read_killable() Oleg Nesterov
@ 2026-05-29 15:37 ` Marco Elver
2026-05-29 17:21 ` Waiman Long
1 sibling, 0 replies; 3+ messages in thread
From: Marco Elver @ 2026-05-29 15:37 UTC (permalink / raw)
To: Oleg Nesterov
Cc: Peter Zijlstra, Ingo Molnar, Will Deacon, Boqun Feng, Waiman Long,
Christian Brauner, linux-kernel
On Fri, 29 May 2026 at 16:17, Oleg Nesterov <oleg@redhat.com> wrote:
>
> We have lock guards for down_read_trylock/interruptible() but
> down_read_killable() is missing.
>
> At least scoped_cond_guard(rwsem_read_kill, signal->exec_update_lock)
> can have a lot of users: __pidfd_fget(), mm_access(), find_mm_struct(),
> kernel_migrate_pages(), and probably more.
>
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Marco Elver <elver@google.com>
> ---
> include/linux/rwsem.h | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h
> index 6a1a7bae5f81..f0cc72d8f0f2 100644
> --- a/include/linux/rwsem.h
> +++ b/include/linux/rwsem.h
> @@ -259,6 +259,7 @@ extern void up_write(struct rw_semaphore *sem) __releases(sem);
> DEFINE_LOCK_GUARD_1(rwsem_read, struct rw_semaphore, down_read(_T->lock), up_read(_T->lock))
> DEFINE_LOCK_GUARD_1_COND(rwsem_read, _try, down_read_trylock(_T->lock))
> DEFINE_LOCK_GUARD_1_COND(rwsem_read, _intr, down_read_interruptible(_T->lock), _RET == 0)
> +DEFINE_LOCK_GUARD_1_COND(rwsem_read, _kill, down_read_killable(_T->lock), _RET == 0)
>
> DECLARE_LOCK_GUARD_1_ATTRS(rwsem_read, __acquires_shared(_T), __releases_shared(*(struct rw_semaphore **)_T))
> #define class_rwsem_read_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(rwsem_read, _T)
> @@ -266,6 +267,8 @@ DECLARE_LOCK_GUARD_1_ATTRS(rwsem_read_try, __acquires_shared(_T), __releases_sha
> #define class_rwsem_read_try_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(rwsem_read_try, _T)
> DECLARE_LOCK_GUARD_1_ATTRS(rwsem_read_intr, __acquires_shared(_T), __releases_shared(*(struct rw_semaphore **)_T))
> #define class_rwsem_read_intr_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(rwsem_read_intr, _T)
> +DECLARE_LOCK_GUARD_1_ATTRS(rwsem_read_kill, __acquires_shared(_T), __releases_shared(*(struct rw_semaphore **)_T))
> +#define class_rwsem_read_kill_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(rwsem_read_kill, _T)
>
> DEFINE_LOCK_GUARD_1(rwsem_write, struct rw_semaphore, down_write(_T->lock), up_write(_T->lock))
> DEFINE_LOCK_GUARD_1_COND(rwsem_write, _try, down_write_trylock(_T->lock))
> --
> 2.52.0
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] locking/rwsem: add scoped guard for down_read_killable()
2026-05-29 14:16 [PATCH] locking/rwsem: add scoped guard for down_read_killable() Oleg Nesterov
2026-05-29 15:37 ` Marco Elver
@ 2026-05-29 17:21 ` Waiman Long
1 sibling, 0 replies; 3+ messages in thread
From: Waiman Long @ 2026-05-29 17:21 UTC (permalink / raw)
To: Oleg Nesterov, Peter Zijlstra, Ingo Molnar, Will Deacon,
Boqun Feng
Cc: Marco Elver, Christian Brauner, linux-kernel
On 5/29/26 10:16 AM, Oleg Nesterov wrote:
> We have lock guards for down_read_trylock/interruptible() but
> down_read_killable() is missing.
>
> At least scoped_cond_guard(rwsem_read_kill, signal->exec_update_lock)
> can have a lot of users: __pidfd_fget(), mm_access(), find_mm_struct(),
> kernel_migrate_pages(), and probably more.
>
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
> ---
> include/linux/rwsem.h | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h
> index 6a1a7bae5f81..f0cc72d8f0f2 100644
> --- a/include/linux/rwsem.h
> +++ b/include/linux/rwsem.h
> @@ -259,6 +259,7 @@ extern void up_write(struct rw_semaphore *sem) __releases(sem);
> DEFINE_LOCK_GUARD_1(rwsem_read, struct rw_semaphore, down_read(_T->lock), up_read(_T->lock))
> DEFINE_LOCK_GUARD_1_COND(rwsem_read, _try, down_read_trylock(_T->lock))
> DEFINE_LOCK_GUARD_1_COND(rwsem_read, _intr, down_read_interruptible(_T->lock), _RET == 0)
> +DEFINE_LOCK_GUARD_1_COND(rwsem_read, _kill, down_read_killable(_T->lock), _RET == 0)
>
> DECLARE_LOCK_GUARD_1_ATTRS(rwsem_read, __acquires_shared(_T), __releases_shared(*(struct rw_semaphore **)_T))
> #define class_rwsem_read_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(rwsem_read, _T)
> @@ -266,6 +267,8 @@ DECLARE_LOCK_GUARD_1_ATTRS(rwsem_read_try, __acquires_shared(_T), __releases_sha
> #define class_rwsem_read_try_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(rwsem_read_try, _T)
> DECLARE_LOCK_GUARD_1_ATTRS(rwsem_read_intr, __acquires_shared(_T), __releases_shared(*(struct rw_semaphore **)_T))
> #define class_rwsem_read_intr_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(rwsem_read_intr, _T)
> +DECLARE_LOCK_GUARD_1_ATTRS(rwsem_read_kill, __acquires_shared(_T), __releases_shared(*(struct rw_semaphore **)_T))
> +#define class_rwsem_read_kill_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(rwsem_read_kill, _T)
>
> DEFINE_LOCK_GUARD_1(rwsem_write, struct rw_semaphore, down_write(_T->lock), up_write(_T->lock))
> DEFINE_LOCK_GUARD_1_COND(rwsem_write, _try, down_write_trylock(_T->lock))
Acked-by: Waiman Long <longman@redhat.com>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2026-05-29 14:16 [PATCH] locking/rwsem: add scoped guard for down_read_killable() Oleg Nesterov
2026-05-29 15:37 ` Marco Elver
2026-05-29 17:21 ` Waiman Long
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