On Tue, 25 Nov 2025 16:22:07 +0800
Leon Hwang <[email protected]> wrote:
> +TRACE_EVENT(page_pool_release_stalled,
> +
> + TP_PROTO(const struct page_pool *pool, int inflight, int sec),
> +
> + TP_ARGS(pool, inflight, sec),
> +
> + TP_STRUCT__entry(
> + __field(const struct page_pool *, pool)
> + __field(int, inflight)
> + __field(int, sec)
> + ),
> +
> + TP_fast_assign(
> + __entry->pool = pool;
> + __entry->inflight = inflight;
> + __entry->sec = sec;
> + ),
> +
> + TP_printk("page_pool=%p id=%d inflight=%d sec=%d",
> + __entry->pool, __entry->pool->user.id, __entry->inflight,
> __entry->sec)
You can't do: __entry->pool->user.id
The TP_fast_assign() is executed when the tracepoint is triggered. The
TP_printk() is executed when the trace is read. That can happen seconds,
minutes, hours, days, even months after the pool was assigned.
That __entry->pool can very well be freed a long time ago.
If you need the id, you need to record it in the TP_fast_assign():
__entry->id = pool->user.id
and print that.
-- Steve
> +);
> +
