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workqueue: Protects wq_unbound_cpumask with wq_pool_attach_mutex
[ Upstream commit99c621ef24
] When unbind_workers() reads wq_unbound_cpumask to set the affinity of freshly-unbound kworkers, it only holds wq_pool_attach_mutex. This isn't sufficient as wq_unbound_cpumask is only protected by wq_pool_mutex. Make wq_unbound_cpumask protected with wq_pool_attach_mutex and also remove the need of temporary saved_cpumask. Fixes:10a5a651e3
("workqueue: Restrict kworker in the offline CPU pool running on housekeeping CPUs") Reported-by: Valentin Schneider <vschneid@redhat.com> Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
parent
807e3596ef
commit
68b2e5d84a
1 changed files with 16 additions and 25 deletions
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@ -326,7 +326,7 @@ static struct rcuwait manager_wait = __RCUWAIT_INITIALIZER(manager_wait);
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static LIST_HEAD(workqueues); /* PR: list of all workqueues */
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static LIST_HEAD(workqueues); /* PR: list of all workqueues */
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static bool workqueue_freezing; /* PL: have wqs started freezing? */
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static bool workqueue_freezing; /* PL: have wqs started freezing? */
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/* PL: allowable cpus for unbound wqs and work items */
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/* PL&A: allowable cpus for unbound wqs and work items */
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static cpumask_var_t wq_unbound_cpumask;
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static cpumask_var_t wq_unbound_cpumask;
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/* CPU where unbound work was last round robin scheduled from this CPU */
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/* CPU where unbound work was last round robin scheduled from this CPU */
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@ -3952,7 +3952,8 @@ static void apply_wqattrs_cleanup(struct apply_wqattrs_ctx *ctx)
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/* allocate the attrs and pwqs for later installation */
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/* allocate the attrs and pwqs for later installation */
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static struct apply_wqattrs_ctx *
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static struct apply_wqattrs_ctx *
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apply_wqattrs_prepare(struct workqueue_struct *wq,
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apply_wqattrs_prepare(struct workqueue_struct *wq,
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const struct workqueue_attrs *attrs)
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const struct workqueue_attrs *attrs,
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const cpumask_var_t unbound_cpumask)
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{
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{
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struct apply_wqattrs_ctx *ctx;
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struct apply_wqattrs_ctx *ctx;
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struct workqueue_attrs *new_attrs, *tmp_attrs;
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struct workqueue_attrs *new_attrs, *tmp_attrs;
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@ -3968,14 +3969,15 @@ apply_wqattrs_prepare(struct workqueue_struct *wq,
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goto out_free;
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goto out_free;
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/*
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/*
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* Calculate the attrs of the default pwq.
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* Calculate the attrs of the default pwq with unbound_cpumask
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* which is wq_unbound_cpumask or to set to wq_unbound_cpumask.
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* If the user configured cpumask doesn't overlap with the
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* If the user configured cpumask doesn't overlap with the
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* wq_unbound_cpumask, we fallback to the wq_unbound_cpumask.
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* wq_unbound_cpumask, we fallback to the wq_unbound_cpumask.
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*/
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*/
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copy_workqueue_attrs(new_attrs, attrs);
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copy_workqueue_attrs(new_attrs, attrs);
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cpumask_and(new_attrs->cpumask, new_attrs->cpumask, wq_unbound_cpumask);
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cpumask_and(new_attrs->cpumask, new_attrs->cpumask, unbound_cpumask);
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if (unlikely(cpumask_empty(new_attrs->cpumask)))
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if (unlikely(cpumask_empty(new_attrs->cpumask)))
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cpumask_copy(new_attrs->cpumask, wq_unbound_cpumask);
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cpumask_copy(new_attrs->cpumask, unbound_cpumask);
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/*
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/*
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* We may create multiple pwqs with differing cpumasks. Make a
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* We may create multiple pwqs with differing cpumasks. Make a
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@ -4072,7 +4074,7 @@ static int apply_workqueue_attrs_locked(struct workqueue_struct *wq,
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wq->flags &= ~__WQ_ORDERED;
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wq->flags &= ~__WQ_ORDERED;
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}
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}
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ctx = apply_wqattrs_prepare(wq, attrs);
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ctx = apply_wqattrs_prepare(wq, attrs, wq_unbound_cpumask);
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if (!ctx)
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if (!ctx)
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return -ENOMEM;
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return -ENOMEM;
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@ -5334,7 +5336,7 @@ void thaw_workqueues(void)
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}
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}
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#endif /* CONFIG_FREEZER */
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#endif /* CONFIG_FREEZER */
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static int workqueue_apply_unbound_cpumask(void)
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static int workqueue_apply_unbound_cpumask(const cpumask_var_t unbound_cpumask)
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{
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{
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LIST_HEAD(ctxs);
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LIST_HEAD(ctxs);
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int ret = 0;
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int ret = 0;
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@ -5350,7 +5352,7 @@ static int workqueue_apply_unbound_cpumask(void)
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if (wq->flags & __WQ_ORDERED)
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if (wq->flags & __WQ_ORDERED)
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continue;
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continue;
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ctx = apply_wqattrs_prepare(wq, wq->unbound_attrs);
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ctx = apply_wqattrs_prepare(wq, wq->unbound_attrs, unbound_cpumask);
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if (!ctx) {
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if (!ctx) {
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ret = -ENOMEM;
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ret = -ENOMEM;
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break;
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break;
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@ -5365,6 +5367,11 @@ static int workqueue_apply_unbound_cpumask(void)
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apply_wqattrs_cleanup(ctx);
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apply_wqattrs_cleanup(ctx);
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}
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}
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if (!ret) {
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mutex_lock(&wq_pool_attach_mutex);
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cpumask_copy(wq_unbound_cpumask, unbound_cpumask);
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mutex_unlock(&wq_pool_attach_mutex);
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}
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return ret;
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return ret;
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}
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}
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@ -5383,7 +5390,6 @@ static int workqueue_apply_unbound_cpumask(void)
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int workqueue_set_unbound_cpumask(cpumask_var_t cpumask)
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int workqueue_set_unbound_cpumask(cpumask_var_t cpumask)
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{
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{
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int ret = -EINVAL;
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int ret = -EINVAL;
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cpumask_var_t saved_cpumask;
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/*
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/*
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* Not excluding isolated cpus on purpose.
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* Not excluding isolated cpus on purpose.
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@ -5397,23 +5403,8 @@ int workqueue_set_unbound_cpumask(cpumask_var_t cpumask)
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goto out_unlock;
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goto out_unlock;
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}
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}
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if (!zalloc_cpumask_var(&saved_cpumask, GFP_KERNEL)) {
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ret = workqueue_apply_unbound_cpumask(cpumask);
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ret = -ENOMEM;
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goto out_unlock;
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}
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/* save the old wq_unbound_cpumask. */
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cpumask_copy(saved_cpumask, wq_unbound_cpumask);
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/* update wq_unbound_cpumask at first and apply it to wqs. */
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cpumask_copy(wq_unbound_cpumask, cpumask);
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ret = workqueue_apply_unbound_cpumask();
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/* restore the wq_unbound_cpumask when failed. */
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if (ret < 0)
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cpumask_copy(wq_unbound_cpumask, saved_cpumask);
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free_cpumask_var(saved_cpumask);
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out_unlock:
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out_unlock:
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apply_wqattrs_unlock();
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apply_wqattrs_unlock();
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}
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}
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