[PATCH 0/2] debugobjects: RT related change and noch annotation

[PATCH 0/2] debugobjects: RT related change and noch annotation

[Sebastian Andrzej Siewior]

The first is a repost of
	https://lore.kernel.org/all/20251106120628.AxWa_Viy@linutronix.de/

the second is a fix of the override annotation.

Sebastian Andrzej Siewior (2):
  debugobjects: Allow to refill the pool before SYSTEM_SCHEDULING
  debugobjects: Use LD_WAIT_CONFIG instead of LD_WAIT_SLEEP

 lib/debugobjects.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

-- 
2.51.0

[PATCH 1/2] debugobjects: Allow to refill the pool before SYSTEM_SCHEDULING

[Sebastian Andrzej Siewior]

The pool of free objects is refilled on several occasions such as object
initialisation. On PREEMPT_RT refilling is limited to preemptible
sections due to sleeping locks used by the memory allocator. The system
boots with disabled interrupts so the pool can not be refilled.

If too many objects are initialized and the pool gets empty then
debugobjects disables itself.

Refiling can also happen early in the boot with disabled interrupts as
long as the scheduler is not operational. If the scheduler can not
preempt a task then a sleeping lock can not be contended.

Allow to additionally refill the pool if the scheduler is not
operational.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 lib/debugobjects.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/debugobjects.c b/lib/debugobjects.c
index 7f50c4480a4e3..7017e5c8f32dd 100644
--- a/lib/debugobjects.c
+++ b/lib/debugobjects.c
@@ -714,7 +714,7 @@ static void debug_objects_fill_pool(void)
 	 * raw_spinlock_t are basically the same type and this lock-type
 	 * inversion works just fine.
 	 */
-	if (!IS_ENABLED(CONFIG_PREEMPT_RT) || preemptible()) {
+	if (!IS_ENABLED(CONFIG_PREEMPT_RT) || preemptible() || system_state < SYSTEM_SCHEDULING) {
 		/*
 		 * Annotate away the spinlock_t inside raw_spinlock_t warning
 		 * by temporarily raising the wait-type to WAIT_SLEEP, matching
-- 
2.51.0

[tip: core/debugobjects] debugobjects: Allow to refill the pool before SYSTEM_SCHEDULING

[tip-bot2 for Sebastian Andrzej Siewior]

The following commit has been merged into the core/debugobjects branch of tip:

Commit-ID:     06e0ae988f6e3499785c407429953ade19c1096b
Gitweb:        https://git.kernel.org/tip/06e0ae988f6e3499785c407429953ade19c1096b
Author:        Sebastian Andrzej Siewior <bigeasy@linutronix.de>
AuthorDate:    Thu, 27 Nov 2025 16:36:51 +01:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Thu, 27 Nov 2025 16:55:34 +01:00

debugobjects: Allow to refill the pool before SYSTEM_SCHEDULING

The pool of free objects is refilled on several occasions such as object
initialisation. On PREEMPT_RT refilling is limited to preemptible
sections due to sleeping locks used by the memory allocator. The system
boots with disabled interrupts so the pool can not be refilled.

If too many objects are initialized and the pool gets empty then
debugobjects disables itself.

Refiling can also happen early in the boot with disabled interrupts as
long as the scheduler is not operational. If the scheduler can not
preempt a task then a sleeping lock can not be contended.

Allow to additionally refill the pool if the scheduler is not
operational.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://patch.msgid.link/20251127153652.291697-2-bigeasy@linutronix.de
---
 lib/debugobjects.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/debugobjects.c b/lib/debugobjects.c
index 7f50c44..7017e5c 100644
--- a/lib/debugobjects.c
+++ b/lib/debugobjects.c
@@ -714,7 +714,7 @@ static void debug_objects_fill_pool(void)
 	 * raw_spinlock_t are basically the same type and this lock-type
 	 * inversion works just fine.
 	 */
-	if (!IS_ENABLED(CONFIG_PREEMPT_RT) || preemptible()) {
+	if (!IS_ENABLED(CONFIG_PREEMPT_RT) || preemptible() || system_state < SYSTEM_SCHEDULING) {
 		/*
 		 * Annotate away the spinlock_t inside raw_spinlock_t warning
 		 * by temporarily raising the wait-type to WAIT_SLEEP, matching

[PATCH 2/2] debugobjects: Use LD_WAIT_CONFIG instead of LD_WAIT_SLEEP

[Sebastian Andrzej Siewior]

fill_pool_map is used to suppress nesting violations caused by acquiring
a spinlock_t (from within the memory allocator) while holding a
raw_spinlock_t. The used annotation is wrong.

LD_WAIT_SLEEP is for always sleeping lock types such as mutex_t.
LD_WAIT_CONFIG is for lock type which are sleeping while spinning on
PREEMPT_RT such as spinlock_t.

Use LD_WAIT_CONFIG as override.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 lib/debugobjects.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/debugobjects.c b/lib/debugobjects.c
index 7017e5c8f32dd..ecf8e7f978e30 100644
--- a/lib/debugobjects.c
+++ b/lib/debugobjects.c
@@ -717,10 +717,10 @@ static void debug_objects_fill_pool(void)
 	if (!IS_ENABLED(CONFIG_PREEMPT_RT) || preemptible() || system_state < SYSTEM_SCHEDULING) {
 		/*
 		 * Annotate away the spinlock_t inside raw_spinlock_t warning
-		 * by temporarily raising the wait-type to WAIT_SLEEP, matching
+		 * by temporarily raising the wait-type to LD_WAIT_CONFIG, matching
 		 * the preemptible() condition above.
 		 */
-		static DEFINE_WAIT_OVERRIDE_MAP(fill_pool_map, LD_WAIT_SLEEP);
+		static DEFINE_WAIT_OVERRIDE_MAP(fill_pool_map, LD_WAIT_CONFIG);
 		lock_map_acquire_try(&fill_pool_map);
 		fill_pool();
 		lock_map_release(&fill_pool_map);
-- 
2.51.0

[tip: core/debugobjects] debugobjects: Use LD_WAIT_CONFIG instead of LD_WAIT_SLEEP

[tip-bot2 for Sebastian Andrzej Siewior]

The following commit has been merged into the core/debugobjects branch of tip:

Commit-ID:     37de2dbc318ee10577c1c2704de5a803e75e55a2
Gitweb:        https://git.kernel.org/tip/37de2dbc318ee10577c1c2704de5a803e75e55a2
Author:        Sebastian Andrzej Siewior <bigeasy@linutronix.de>
AuthorDate:    Thu, 27 Nov 2025 16:36:52 +01:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Thu, 27 Nov 2025 16:55:34 +01:00

debugobjects: Use LD_WAIT_CONFIG instead of LD_WAIT_SLEEP

fill_pool_map is used to suppress nesting violations caused by acquiring
a spinlock_t (from within the memory allocator) while holding a
raw_spinlock_t. The used annotation is wrong.

LD_WAIT_SLEEP is for always sleeping lock types such as mutex_t.
LD_WAIT_CONFIG is for lock type which are sleeping while spinning on
PREEMPT_RT such as spinlock_t.

Use LD_WAIT_CONFIG as override.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://patch.msgid.link/20251127153652.291697-3-bigeasy@linutronix.de
---
 lib/debugobjects.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/debugobjects.c b/lib/debugobjects.c
index 7017e5c..ecf8e7f 100644
--- a/lib/debugobjects.c
+++ b/lib/debugobjects.c
@@ -717,10 +717,10 @@ static void debug_objects_fill_pool(void)
 	if (!IS_ENABLED(CONFIG_PREEMPT_RT) || preemptible() || system_state < SYSTEM_SCHEDULING) {
 		/*
 		 * Annotate away the spinlock_t inside raw_spinlock_t warning
-		 * by temporarily raising the wait-type to WAIT_SLEEP, matching
+		 * by temporarily raising the wait-type to LD_WAIT_CONFIG, matching
 		 * the preemptible() condition above.
 		 */
-		static DEFINE_WAIT_OVERRIDE_MAP(fill_pool_map, LD_WAIT_SLEEP);
+		static DEFINE_WAIT_OVERRIDE_MAP(fill_pool_map, LD_WAIT_CONFIG);
 		lock_map_acquire_try(&fill_pool_map);
 		fill_pool();
 		lock_map_release(&fill_pool_map);

Re: [PATCH 0/2] debugobjects: RT related change and noch annotation

[Luis Claudio R. Goncalves]

On Thu, Nov 27, 2025 at 04:36:50PM +0100, Sebastian Andrzej Siewior wrote:
> The first is a repost of
> 	https://lore.kernel.org/all/20251106120628.AxWa_Viy@linutronix.de/
> 
> the second is a fix of the override annotation.
> 
> Sebastian Andrzej Siewior (2):
>   debugobjects: Allow to refill the pool before SYSTEM_SCHEDULING
>   debugobjects: Use LD_WAIT_CONFIG instead of LD_WAIT_SLEEP

To the series:

Reviewed-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>

Luis
 
>  lib/debugobjects.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> -- 
> 2.51.0
> 
> 
---end quoted text---