[PATCH] rcu: mark lockdep_assert_rcu_helper() __always_inline

[PATCH] rcu: mark lockdep_assert_rcu_helper() __always_inline

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

There are some configurations in which lockdep_assert_rcu_helper() ends up
not being inlined, for some reason. This leads to a link failure because
now the caller tries to pass a nonexistant __ctx_lock_RCU structure:

ld: lib/test_context-analysis.o: in function `test_rcu_assert_variants':
test_context-analysis.c:(.text+0x275c): undefined reference to `RCU'
ld: test_context-analysis.c:(.text+0x276c): undefined reference to `RCU_BH'
ld: test_context-analysis.c:(.text+0x2774): undefined reference to `RCU_SCHED'

I saw this in one out of many 32-bit arm builds using gcc-15.2, but
it probably happens in others as well.

Mark this function as __always_inline to fix the build.

Fixes: fe00f6e84621 ("rcu: Support Clang's context analysis")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 include/linux/rcupdate.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index ea1e979b290e..7729fef249e1 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -406,7 +406,7 @@ static inline void rcu_preempt_sleep_check(void) { }
 
 // See RCU_LOCKDEP_WARN() for an explanation of the double call to
 // debug_lockdep_rcu_enabled().
-static inline bool lockdep_assert_rcu_helper(bool c, const struct __ctx_lock_RCU *ctx)
+static __always_inline bool lockdep_assert_rcu_helper(bool c, const struct __ctx_lock_RCU *ctx)
 	__assumes_shared_ctx_lock(RCU) __assumes_shared_ctx_lock(ctx)
 {
 	return debug_lockdep_rcu_enabled() &&
-- 
2.39.5

Re: [PATCH] rcu: mark lockdep_assert_rcu_helper() __always_inline

[Peter Zijlstra]

On Mon, Feb 02, 2026 at 10:55:01AM +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> There are some configurations in which lockdep_assert_rcu_helper() ends up
> not being inlined, for some reason. This leads to a link failure because
> now the caller tries to pass a nonexistant __ctx_lock_RCU structure:
> 
> ld: lib/test_context-analysis.o: in function `test_rcu_assert_variants':
> test_context-analysis.c:(.text+0x275c): undefined reference to `RCU'
> ld: test_context-analysis.c:(.text+0x276c): undefined reference to `RCU_BH'
> ld: test_context-analysis.c:(.text+0x2774): undefined reference to `RCU_SCHED'
> 
> I saw this in one out of many 32-bit arm builds using gcc-15.2, but
> it probably happens in others as well.
> 
> Mark this function as __always_inline to fix the build.
> 
> Fixes: fe00f6e84621 ("rcu: Support Clang's context analysis")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Thanks!

Re: [PATCH] rcu: mark lockdep_assert_rcu_helper() __always_inline

[Paul E. McKenney]

On Mon, Feb 02, 2026 at 10:55:01AM +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> There are some configurations in which lockdep_assert_rcu_helper() ends up
> not being inlined, for some reason. This leads to a link failure because
> now the caller tries to pass a nonexistant __ctx_lock_RCU structure:
> 
> ld: lib/test_context-analysis.o: in function `test_rcu_assert_variants':
> test_context-analysis.c:(.text+0x275c): undefined reference to `RCU'
> ld: test_context-analysis.c:(.text+0x276c): undefined reference to `RCU_BH'
> ld: test_context-analysis.c:(.text+0x2774): undefined reference to `RCU_SCHED'
> 
> I saw this in one out of many 32-bit arm builds using gcc-15.2, but
> it probably happens in others as well.
> 
> Mark this function as __always_inline to fix the build.
> 
> Fixes: fe00f6e84621 ("rcu: Support Clang's context analysis")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Reviewed-by: Paul E. McKenney <paulmck@kernel.org>

> ---
>  include/linux/rcupdate.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
> index ea1e979b290e..7729fef249e1 100644
> --- a/include/linux/rcupdate.h
> +++ b/include/linux/rcupdate.h
> @@ -406,7 +406,7 @@ static inline void rcu_preempt_sleep_check(void) { }
>  
>  // See RCU_LOCKDEP_WARN() for an explanation of the double call to
>  // debug_lockdep_rcu_enabled().
> -static inline bool lockdep_assert_rcu_helper(bool c, const struct __ctx_lock_RCU *ctx)
> +static __always_inline bool lockdep_assert_rcu_helper(bool c, const struct __ctx_lock_RCU *ctx)
>  	__assumes_shared_ctx_lock(RCU) __assumes_shared_ctx_lock(ctx)
>  {
>  	return debug_lockdep_rcu_enabled() &&
> -- 
> 2.39.5
> 

[tip: locking/core] rcu: Mark lockdep_assert_rcu_helper() __always_inline

[tip-bot2 for Arnd Bergmann]

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

Commit-ID:     451c3a0356099483218535aed17fcf94ab5764a3
Gitweb:        https://git.kernel.org/tip/451c3a0356099483218535aed17fcf94ab5764a3
Author:        Arnd Bergmann <arnd@arndb.de>
AuthorDate:    Mon, 02 Feb 2026 10:55:01 +01:00
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Mon, 02 Feb 2026 22:02:49 +01:00

rcu: Mark lockdep_assert_rcu_helper() __always_inline

There are some configurations in which lockdep_assert_rcu_helper() ends up
not being inlined, for some reason. This leads to a link failure because
now the caller tries to pass a nonexistant __ctx_lock_RCU structure:

ld: lib/test_context-analysis.o: in function `test_rcu_assert_variants':
test_context-analysis.c:(.text+0x275c): undefined reference to `RCU'
ld: test_context-analysis.c:(.text+0x276c): undefined reference to `RCU_BH'
ld: test_context-analysis.c:(.text+0x2774): undefined reference to `RCU_SCHED'

I saw this in one out of many 32-bit arm builds using gcc-15.2, but
it probably happens in others as well.

Mark this function as __always_inline to fix the build.

Fixes: fe00f6e84621 ("rcu: Support Clang's context analysis")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://patch.msgid.link/20260202095507.1237440-1-arnd@kernel.org
---
 include/linux/rcupdate.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index d828a46..f0aa48b 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -435,7 +435,7 @@ static inline void rcu_preempt_sleep_check(void) { }
 
 // See RCU_LOCKDEP_WARN() for an explanation of the double call to
 // debug_lockdep_rcu_enabled().
-static inline bool lockdep_assert_rcu_helper(bool c, const struct __ctx_lock_RCU *ctx)
+static __always_inline bool lockdep_assert_rcu_helper(bool c, const struct __ctx_lock_RCU *ctx)
 	__assumes_shared_ctx_lock(RCU) __assumes_shared_ctx_lock(ctx)
 {
 	return debug_lockdep_rcu_enabled() &&