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

["Paul E. McKenney" <paulmck@kernel.org>]

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
>