Re: [PATCH 6.8 002/715] workqueue.c: Increase workqueue name length

Ron Economos
2024-03-26T09:36:26Z

On 3/24/24 3:23 PM, Sasha Levin wrote:
> From: Audra Mitchell <audra@redhat.com>
>
> [ Upstream commit 31c89007285d365aa36f71d8fb0701581c770a27 ]
>
> Currently we limit the size of the workqueue name to 24 characters due to
> commit ecf6881ff349 ("workqueue: make workqueue->name[] fixed len")
> Increase the size to 32 characters and print a warning in the event
> the requested name is larger than the limit of 32 characters.
>
> Signed-off-by: Audra Mitchell <audra@redhat.com>
> Signed-off-by: Tejun Heo <tj@kernel.org>
> Stable-dep-of: 5797b1c18919 ("workqueue: Implement system-wide nr_active enforcement for unbound workqueues")
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
> kernel/workqueue.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/workqueue.c b/kernel/workqueue.c
> index 7b482a26d7419..8a06fddb23e66 100644
> --- a/kernel/workqueue.c
> +++ b/kernel/workqueue.c
> @@ -108,7 +108,7 @@ enum {
> RESCUER_NICE_LEVEL = MIN_NICE,
> HIGHPRI_NICE_LEVEL = MIN_NICE,
>
> - WQ_NAME_LEN = 24,
> + WQ_NAME_LEN = 32,
> };
>
> /*
> @@ -4666,6 +4666,7 @@ struct workqueue_struct *alloc_workqueue(const char *fmt,
> va_list args;
> struct workqueue_struct *wq;
> struct pool_workqueue *pwq;
> + int len;
>
> /*
> * Unbound && max_active == 1 used to imply ordered, which is no longer
> @@ -4692,9 +4693,12 @@ struct workqueue_struct *alloc_workqueue(const char *fmt,
> }
>
> va_start(args, max_active);
> - vsnprintf(wq->name, sizeof(wq->name), fmt, args);
> + len = vsnprintf(wq->name, sizeof(wq->name), fmt, args);
> va_end(args);
>
> + if (len >= WQ_NAME_LEN)
> + pr_warn_once("workqueue: name exceeds WQ_NAME_LEN. Truncating to: %s\n", wq->name);
> +
> max_active = max_active ?: WQ_DFL_ACTIVE;
> max_active = wq_clamp_max_active(max_active, flags, wq->name);
>

Minor issue. The upstream commit
8318d6a6362f5903edb4c904a8dd447e59be4ad1 "workqueue: Shorten
events_freezable_power_efficient name" goes with this patch. Otherwise
the warning "kernel: workqueue: name exceeds WQ_NAME_LEN. Truncating to:
events_freezable_power_efficien" occurs.

Same for 6.7.11-rc2 and 6.6.23-rc2.