Re: [PATCH v19 10/40] dept: apply sdt_might_sleep_{start, end}() to wait_for_completion()/complete()

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] The `init_completion_map()` macro ignores the provided lockdep map argument `m` and sets `dmap` to `NULL`. This forces all generic wrappers like `flush_work()` to share a single, monolithic dependency class generated at the `wait_for_completion` macro call site.
--

commit c25e7af1e00aa68cd5900db21d080eadb8fccd71
Author: Byungchul Park <byungchul@sk.com>

dept: apply sdt_might_sleep_{start,end}() to wait_for_completion()/complete()

This commit enables the DEPT (Dependency Tracker) to track dependencies
introduced by wait_for_completion() and complete() calls. It adds a
dept_map to the completion structure and applies the appropriate sleep
start and end annotations.

> diff --git a/include/linux/completion.h b/include/linux/completion.h
> index fb29156765743..bd2c207481d68 100644
> --- a/include/linux/completion.h
> +++ b/include/linux/completion.h
[ ... ]
> @@ -26,14 +27,33 @@
>  struct completion {
>  	unsigned int done;
>  	struct swait_queue_head wait;
> +	struct dept_map dmap;
>  };
>  
> +#define init_completion(x)				\
> +do {							\
> +	sdt_map_init(&(x)->dmap);			\
> +	__init_completion(x);				\
> +} while (0)
> +
> +/*
> + * XXX: No use cases for now. Fill the body when needed.
> + */
>  #define init_completion_map(x, m) init_completion(x)

[Severity: High]
Does this macro cause independent dependency graphs to merge? By ignoring the
lockdep map argument m and calling init_completion(x) instead, it seems
generic wrappers like flush_work() will be forced to share a single
monolithic dependency class generated at the wait site.

Could this lead DEPT to report false-positive deadlocks during normal
operations? For example, if Work A flushes Work B, and Work B flushes
Work C, both use the same flush_work() completion class. DEPT might see
Work B both waiting on and satisfying this global class, erroneously
detecting a self-cycle.

> -static inline void complete_acquire(struct completion *x) {}
> -static inline void complete_release(struct completion *x) {}

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Sashiko AI review · https://sashiko.dev/#/patchset/20260706061928.66713-1-byungchul@sk.com?part=10