diff options
| author | Breno Leitao <leitao@debian.org> | 2026-08-12 09:03:19 -0700 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2026-08-12 07:06:17 -1000 |
| commit | 1d125f0e6cbd34f6260affac85987201b6899ed0 (patch) | |
| tree | 4a8994099f594fe3b6a562f76baac3251057b423 /kernel/workqueue.c | |
| parent | 7aef540078adc7cdfa5ee2c9784269b49f51b539 (diff) | |
workqueue: use RCU accessors when populating wq->cpu_pwq
wq->cpu_pwq holds RCU-protected pwq pointers, but the percpu allocation
path fills it in with plain loads and stores, which sparse flags:
kernel/workqueue.c:5682:57: sparse: incorrect type in initializer (different address spaces) @@ expected struct pool_workqueue **pwq_p @@ got struct pool_workqueue [noderef] __rcu ** @@
Allocate the array as __rcu pointers and publish each pwq with
rcu_assign_pointer() once it is initialized and linked, the order
install_unbound_pwq() uses.
The warnings are not new: commit 79f23600bc7b ("workqueue: factor out
get_percpu_pool()") only turned the flagged assignment into an
initializer.
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202608120931.tvTzq1gD-lkp@intel.com/
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel/workqueue.c')
| -rw-r--r-- | kernel/workqueue.c | 19 |
1 files changed, 12 insertions, 7 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c index e66ee1016568..e602ab2049a7 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -5681,21 +5681,23 @@ out_unlock: static int alloc_and_link_percpu_pwqs(struct workqueue_struct *wq) { + struct pool_workqueue *pwq; int cpu; for_each_possible_cpu(cpu) { - struct pool_workqueue **pwq_p = per_cpu_ptr(wq->cpu_pwq, cpu); struct worker_pool *pool = get_percpu_pool(wq, cpu); - *pwq_p = kmem_cache_alloc_node(pwq_cache, GFP_KERNEL, pool->node); - if (!*pwq_p) + pwq = kmem_cache_alloc_node(pwq_cache, GFP_KERNEL, pool->node); + if (!pwq) return -ENOMEM; - init_pwq(*pwq_p, wq, pool); + init_pwq(pwq, wq, pool); mutex_lock(&wq->mutex); - link_pwq(*pwq_p); + link_pwq(pwq); mutex_unlock(&wq->mutex); + + rcu_assign_pointer(*per_cpu_ptr(wq->cpu_pwq, cpu), pwq); } return 0; @@ -5708,7 +5710,7 @@ static int alloc_and_link_pwqs(struct workqueue_struct *wq) lockdep_assert_held(&wq_pool_mutex); - wq->cpu_pwq = alloc_percpu(struct pool_workqueue *); + wq->cpu_pwq = alloc_percpu(struct pool_workqueue __rcu *); if (!wq->cpu_pwq) goto enomem; @@ -5734,8 +5736,11 @@ static int alloc_and_link_pwqs(struct workqueue_struct *wq) enomem: if (wq->cpu_pwq) { for_each_possible_cpu(cpu) { - struct pool_workqueue *pwq = *per_cpu_ptr(wq->cpu_pwq, cpu); + struct pool_workqueue __rcu **slot; + struct pool_workqueue *pwq; + slot = per_cpu_ptr(wq->cpu_pwq, cpu); + pwq = rcu_access_pointer(*slot); if (pwq) { /* * Unlink pwq from wq->pwqs since link_pwq() |