From: tip-bot for Juri Lelli <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: juri.lelli@redhat.com, linux-kernel@vger.kernel.org,
dietmar.eggemann@arm.com, mingo@kernel.org, hpa@zytor.com,
tglx@linutronix.de, torvalds@linux-foundation.org,
peterz@infradead.org
Subject: [tip:sched/core] cgroup/cpuset: Change cpuset_rwsem and hotplug lock order
Date: Thu, 25 Jul 2019 09:23:26 -0700 [thread overview]
Message-ID: <tip-d74b27d63a8bebe2fe634944e4ebdc7b10db7a39@git.kernel.org> (raw)
In-Reply-To: <20190719140000.31694-7-juri.lelli@redhat.com>
Commit-ID: d74b27d63a8bebe2fe634944e4ebdc7b10db7a39
Gitweb: https://git.kernel.org/tip/d74b27d63a8bebe2fe634944e4ebdc7b10db7a39
Author: Juri Lelli <juri.lelli@redhat.com>
AuthorDate: Fri, 19 Jul 2019 15:59:58 +0200
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Thu, 25 Jul 2019 15:55:03 +0200
cgroup/cpuset: Change cpuset_rwsem and hotplug lock order
cpuset_rwsem is going to be acquired from sched_setscheduler() with a
following patch. There are however paths (e.g., spawn_ksoftirqd) in
which sched_scheduler() is eventually called while holding hotplug lock;
this creates a dependecy between hotplug lock (to be always acquired
first) and cpuset_rwsem (to be always acquired after hotplug lock).
Fix paths which currently take the two locks in the wrong order (after
a following patch is applied).
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: bristot@redhat.com
Cc: claudio@evidence.eu.com
Cc: lizefan@huawei.com
Cc: longman@redhat.com
Cc: luca.abeni@santannapisa.it
Cc: mathieu.poirier@linaro.org
Cc: rostedt@goodmis.org
Cc: tj@kernel.org
Cc: tommaso.cucinotta@santannapisa.it
Link: https://lkml.kernel.org/r/20190719140000.31694-7-juri.lelli@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
include/linux/cpuset.h | 8 ++++----
kernel/cgroup/cpuset.c | 22 +++++++++++++++++-----
2 files changed, 21 insertions(+), 9 deletions(-)
diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h
index 934633a05d20..7f1478c26a33 100644
--- a/include/linux/cpuset.h
+++ b/include/linux/cpuset.h
@@ -40,14 +40,14 @@ static inline bool cpusets_enabled(void)
static inline void cpuset_inc(void)
{
- static_branch_inc(&cpusets_pre_enable_key);
- static_branch_inc(&cpusets_enabled_key);
+ static_branch_inc_cpuslocked(&cpusets_pre_enable_key);
+ static_branch_inc_cpuslocked(&cpusets_enabled_key);
}
static inline void cpuset_dec(void)
{
- static_branch_dec(&cpusets_enabled_key);
- static_branch_dec(&cpusets_pre_enable_key);
+ static_branch_dec_cpuslocked(&cpusets_enabled_key);
+ static_branch_dec_cpuslocked(&cpusets_pre_enable_key);
}
extern int cpuset_init(void);
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index e1a8d168c5e9..5c5014caa23c 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -973,8 +973,8 @@ static void rebuild_sched_domains_locked(void)
cpumask_var_t *doms;
int ndoms;
+ lockdep_assert_cpus_held();
percpu_rwsem_assert_held(&cpuset_rwsem);
- get_online_cpus();
/*
* We have raced with CPU hotplug. Don't do anything to avoid
@@ -983,19 +983,17 @@ static void rebuild_sched_domains_locked(void)
*/
if (!top_cpuset.nr_subparts_cpus &&
!cpumask_equal(top_cpuset.effective_cpus, cpu_active_mask))
- goto out;
+ return;
if (top_cpuset.nr_subparts_cpus &&
!cpumask_subset(top_cpuset.effective_cpus, cpu_active_mask))
- goto out;
+ return;
/* Generate domain masks and attrs */
ndoms = generate_sched_domains(&doms, &attr);
/* Have scheduler rebuild the domains */
partition_and_rebuild_sched_domains(ndoms, doms, attr);
-out:
- put_online_cpus();
}
#else /* !CONFIG_SMP */
static void rebuild_sched_domains_locked(void)
@@ -1005,9 +1003,11 @@ static void rebuild_sched_domains_locked(void)
void rebuild_sched_domains(void)
{
+ get_online_cpus();
percpu_down_write(&cpuset_rwsem);
rebuild_sched_domains_locked();
percpu_up_write(&cpuset_rwsem);
+ put_online_cpus();
}
/**
@@ -2245,6 +2245,7 @@ static int cpuset_write_u64(struct cgroup_subsys_state *css, struct cftype *cft,
cpuset_filetype_t type = cft->private;
int retval = 0;
+ get_online_cpus();
percpu_down_write(&cpuset_rwsem);
if (!is_cpuset_online(cs)) {
retval = -ENODEV;
@@ -2282,6 +2283,7 @@ static int cpuset_write_u64(struct cgroup_subsys_state *css, struct cftype *cft,
}
out_unlock:
percpu_up_write(&cpuset_rwsem);
+ put_online_cpus();
return retval;
}
@@ -2292,6 +2294,7 @@ static int cpuset_write_s64(struct cgroup_subsys_state *css, struct cftype *cft,
cpuset_filetype_t type = cft->private;
int retval = -ENODEV;
+ get_online_cpus();
percpu_down_write(&cpuset_rwsem);
if (!is_cpuset_online(cs))
goto out_unlock;
@@ -2306,6 +2309,7 @@ static int cpuset_write_s64(struct cgroup_subsys_state *css, struct cftype *cft,
}
out_unlock:
percpu_up_write(&cpuset_rwsem);
+ put_online_cpus();
return retval;
}
@@ -2344,6 +2348,7 @@ static ssize_t cpuset_write_resmask(struct kernfs_open_file *of,
kernfs_break_active_protection(of->kn);
flush_work(&cpuset_hotplug_work);
+ get_online_cpus();
percpu_down_write(&cpuset_rwsem);
if (!is_cpuset_online(cs))
goto out_unlock;
@@ -2369,6 +2374,7 @@ static ssize_t cpuset_write_resmask(struct kernfs_open_file *of,
free_cpuset(trialcs);
out_unlock:
percpu_up_write(&cpuset_rwsem);
+ put_online_cpus();
kernfs_unbreak_active_protection(of->kn);
css_put(&cs->css);
flush_workqueue(cpuset_migrate_mm_wq);
@@ -2499,6 +2505,7 @@ static ssize_t sched_partition_write(struct kernfs_open_file *of, char *buf,
return -EINVAL;
css_get(&cs->css);
+ get_online_cpus();
percpu_down_write(&cpuset_rwsem);
if (!is_cpuset_online(cs))
goto out_unlock;
@@ -2506,6 +2513,7 @@ static ssize_t sched_partition_write(struct kernfs_open_file *of, char *buf,
retval = update_prstate(cs, val);
out_unlock:
percpu_up_write(&cpuset_rwsem);
+ put_online_cpus();
css_put(&cs->css);
return retval ?: nbytes;
}
@@ -2711,6 +2719,7 @@ static int cpuset_css_online(struct cgroup_subsys_state *css)
if (!parent)
return 0;
+ get_online_cpus();
percpu_down_write(&cpuset_rwsem);
set_bit(CS_ONLINE, &cs->flags);
@@ -2763,6 +2772,7 @@ static int cpuset_css_online(struct cgroup_subsys_state *css)
spin_unlock_irq(&callback_lock);
out_unlock:
percpu_up_write(&cpuset_rwsem);
+ put_online_cpus();
return 0;
}
@@ -2781,6 +2791,7 @@ static void cpuset_css_offline(struct cgroup_subsys_state *css)
{
struct cpuset *cs = css_cs(css);
+ get_online_cpus();
percpu_down_write(&cpuset_rwsem);
if (is_partition_root(cs))
@@ -2801,6 +2812,7 @@ static void cpuset_css_offline(struct cgroup_subsys_state *css)
clear_bit(CS_ONLINE, &cs->flags);
percpu_up_write(&cpuset_rwsem);
+ put_online_cpus();
}
static void cpuset_css_free(struct cgroup_subsys_state *css)
next prev parent reply other threads:[~2019-07-25 16:24 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-19 13:59 [PATCH v9 0/8] sched/deadline: fix cpusets bandwidth accounting Juri Lelli
2019-07-19 13:59 ` [PATCH v9 1/8] sched/topology: Adding function partition_sched_domains_locked() Juri Lelli
2019-07-25 16:19 ` [tip:sched/core] sched/topology: Add partition_sched_domains_locked() tip-bot for Mathieu Poirier
2019-07-19 13:59 ` [PATCH v9 2/8] sched/core: Streamlining calls to task_rq_unlock() Juri Lelli
2019-07-22 8:21 ` Dietmar Eggemann
2019-07-22 8:32 ` Juri Lelli
2019-07-22 9:08 ` Dietmar Eggemann
2019-07-23 10:32 ` Peter Zijlstra
2019-07-23 10:31 ` Peter Zijlstra
2019-07-23 13:11 ` Tejun Heo
2019-07-23 14:58 ` Juri Lelli
2019-07-25 16:20 ` [tip:sched/core] sched/core: Streamle " tip-bot for Mathieu Poirier
2019-07-19 13:59 ` [PATCH v9 3/8] cpuset: Rebuild root domain deadline accounting information Juri Lelli
2019-07-25 13:53 ` Ingo Molnar
2019-07-25 13:56 ` Ingo Molnar
2019-07-25 14:07 ` Juri Lelli
2019-07-25 16:00 ` Mathieu Poirier
2019-07-25 16:21 ` [tip:sched/core] cpusets: " tip-bot for Mathieu Poirier
2019-11-04 18:57 ` [PATCH v9 3/8] cpuset: " Michal Koutný
2019-11-05 12:03 ` Michal Koutný
2022-12-16 23:35 ` Qais Yousef
2022-12-17 2:26 ` Waiman Long
2022-12-17 22:10 ` Qais Yousef
2022-12-19 8:07 ` Vincent Guittot
2022-12-20 11:43 ` Qais Yousef
2023-01-15 16:41 ` Qais Yousef
2019-07-19 13:59 ` [PATCH v9 4/8] sched/deadline: Fix bandwidth accounting at all levels after offline migration Juri Lelli
2019-07-22 11:07 ` Dietmar Eggemann
2019-07-22 12:28 ` Juri Lelli
2019-07-22 13:21 ` Dietmar Eggemann
2019-07-22 13:35 ` Juri Lelli
2019-07-22 14:29 ` Dietmar Eggemann
2019-07-25 16:21 ` [tip:sched/core] " tip-bot for Juri Lelli
2019-07-19 13:59 ` [PATCH v9 5/8] cgroup/cpuset: convert cpuset_mutex to percpu_rwsem Juri Lelli
2019-07-25 16:22 ` [tip:sched/core] cgroup/cpuset: Convert " tip-bot for Juri Lelli
2019-07-19 13:59 ` [PATCH v9 6/8] cgroup/cpuset: Change cpuset_rwsem and hotplug lock order Juri Lelli
2019-07-25 16:23 ` tip-bot for Juri Lelli [this message]
2019-07-19 13:59 ` [PATCH v9 7/8] rcu/tree: Setschedule gp ktread to SCHED_FIFO outside of atomic region Juri Lelli
2019-07-25 16:24 ` [tip:sched/core] rcu/tree: Call setschedule() " tip-bot for Juri Lelli
2019-07-19 14:00 ` [PATCH v9 8/8] sched/core: Prevent race condition between cpuset and __sched_setscheduler() Juri Lelli
2019-07-25 16:24 ` [tip:sched/core] " tip-bot for Juri Lelli
2019-07-24 8:45 ` [PATCH v9 0/8] sched/deadline: fix cpusets bandwidth accounting Dietmar Eggemann
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