From: Juergen Gross <jgross@suse.com>
To: xen-devel@lists.xenproject.org
Cc: Juergen Gross <jgross@suse.com>,
Stefano Stabellini <sstabellini@kernel.org>,
Julien Grall <julien@xen.org>, Wei Liu <wl@xen.org>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Ian Jackson <ian.jackson@eu.citrix.com>,
George Dunlap <george.dunlap@citrix.com>,
Jan Beulich <jbeulich@suse.com>
Subject: [Xen-devel] [PATCH v3 4/6] xen/rcu: fix rcu_lock_domain()
Date: Wed, 4 Mar 2020 07:32:10 +0100 [thread overview]
Message-ID: <20200304063212.20843-5-jgross@suse.com> (raw)
In-Reply-To: <20200304063212.20843-1-jgross@suse.com>
rcu_lock_domain() misuses the domain structure as rcu lock, which is
working only as long as rcu_read_lock() isn't evaluating the lock.
Fix that by adding a rcu lock to struct domain and use that for
rcu_lock_domain().
Signed-off-by: Juergen Gross <jgross@suse.com>
---
xen/common/domain.c | 1 +
xen/include/xen/rcupdate.h | 1 +
xen/include/xen/sched.h | 6 ++++--
3 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/xen/common/domain.c b/xen/common/domain.c
index 6ad458fa6b..b4eb476a9c 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -398,6 +398,7 @@ struct domain *domain_create(domid_t domid,
goto fail;
atomic_set(&d->refcnt, 1);
+ RCU_READ_LOCK_INIT(&d->rcu_lock);
spin_lock_init_prof(d, domain_lock);
spin_lock_init_prof(d, page_alloc_lock);
spin_lock_init(&d->hypercall_deadlock_mutex);
diff --git a/xen/include/xen/rcupdate.h b/xen/include/xen/rcupdate.h
index 87f35b7704..31c8b86d13 100644
--- a/xen/include/xen/rcupdate.h
+++ b/xen/include/xen/rcupdate.h
@@ -65,6 +65,7 @@ int rcu_needs_cpu(int cpu);
struct _rcu_read_lock {};
typedef struct _rcu_read_lock rcu_read_lock_t;
#define DEFINE_RCU_READ_LOCK(x) rcu_read_lock_t x
+#define RCU_READ_LOCK_INIT(x)
/**
* rcu_read_lock - mark the beginning of an RCU read-side critical section.
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index 3a4f43098c..647e4d31fb 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -348,6 +348,8 @@ struct domain
shared_info_t *shared_info; /* shared data area */
+ rcu_read_lock_t rcu_lock;
+
spinlock_t domain_lock;
spinlock_t page_alloc_lock; /* protects all the following fields */
@@ -634,13 +636,13 @@ int rcu_lock_live_remote_domain_by_id(domid_t dom, struct domain **d);
static inline void rcu_unlock_domain(struct domain *d)
{
if ( d != current->domain )
- rcu_read_unlock(d);
+ rcu_read_unlock(&d->rcu_lock);
}
static inline struct domain *rcu_lock_domain(struct domain *d)
{
if ( d != current->domain )
- rcu_read_lock(d);
+ rcu_read_lock(&d->rcu_lock);
return d;
}
--
2.16.4
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next prev parent reply other threads:[~2020-03-04 6:32 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-04 6:32 [Xen-devel] [PATCH v3 0/6] xen/rcu: let rcu work better with core scheduling Juergen Gross
2020-03-04 6:32 ` [Xen-devel] [PATCH v3 1/6] xen/rcu: use rcu softirq for forcing quiescent state Juergen Gross
2020-03-04 6:32 ` [Xen-devel] [PATCH v3 2/6] xen/rcu: don't use stop_machine_run() for rcu_barrier() Juergen Gross
2020-03-04 6:32 ` [Xen-devel] [PATCH v3 3/6] xen: add process_pending_softirqs_norcu() for keyhandlers Juergen Gross
2020-03-04 6:32 ` Juergen Gross [this message]
2020-03-04 6:32 ` [Xen-devel] [PATCH v3 5/6] xen/rcu: add assertions to debug build Juergen Gross
2020-03-04 13:42 ` Julien Grall
2020-03-06 14:35 ` Jürgen Groß
2020-03-06 16:08 ` Julien Grall
2020-03-04 6:32 ` [Xen-devel] [PATCH v3 6/6] xen/rcu: add per-lock counter in debug builds Juergen Gross
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