> diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
> index c242fe49af4c..401f8dfd05d3 100644
> --- a/include/linux/ftrace.h
> +++ b/include/linux/ftrace.h
> @@ -415,6 +415,7 @@ struct ftrace_hash *alloc_ftrace_hash(int size_bits);
> void free_ftrace_hash(struct ftrace_hash *hash);
> struct ftrace_func_entry *add_ftrace_hash_entry_direct(struct ftrace_hash
> *hash,
> unsigned long ip,
> unsigned long direct);
> +unsigned long ftrace_hash_count(struct ftrace_hash *hash);
>
> /* The hash used to know what functions callbacks trace */
> struct ftrace_ops_hash {
[ ... ]
> diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
> index 413310912609..68a071e80f32 100644
> --- a/kernel/trace/ftrace.c
> +++ b/kernel/trace/ftrace.c
> @@ -6288,11 +6288,16 @@ int modify_ftrace_direct(struct ftrace_ops *ops,
> unsigned long addr)
> }
> EXPORT_SYMBOL_GPL(modify_ftrace_direct);
>
> -static unsigned long hash_count(struct ftrace_hash *hash)
> +static inline unsigned long hash_count(struct ftrace_hash *hash)
> {
> return hash ? hash->count : 0;
> }
>
> +unsigned long ftrace_hash_count(struct ftrace_hash *hash)
> +{
> + return hash_count(hash);
> +}
^^^^
Will this cause a linker error on some kernel configurations?
The function ftrace_hash_count() is declared in include/linux/ftrace.h under
CONFIG_DYNAMIC_FTRACE, but this definition appears in kernel/trace/ftrace.c
inside a section guarded by CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS (which
extends from around modify_ftrace_direct() to several hundred lines below).
On architectures where CONFIG_DYNAMIC_FTRACE=y but
CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS=n, code that calls
ftrace_hash_count() would compile successfully but fail to link since no
definition would be present in the built kernel.
This was raised by [email protected] on the v5 review:
https://lore.kernel.org/all/[email protected]/
> +
> /**
> * hash_add - adds two struct ftrace_hash and returns the result
> * @a: struct ftrace_hash object
---
AI reviewed your patch. Please fix the bug or email reply why it's not a bug.
See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md
CI run summary: https://github.com/kernel-patches/bpf/actions/runs/24598000047
