[ANNOUNCE] v5.16-rc3-rt6
From: Sebastian Andrzej Siewior
Date: Tue Nov 30 2021 - 10:22:26 EST
Dear RT folks!
I'm pleased to announce the v5.16-rc3-rt6 patch set.
Changes since v5.16-rc3-rt5:
- ARM64 implemented HAVE_POSIX_CPU_TIMERS_TASK_WORK and it is now
possible to enable KVM and PREEMPT_RT. Patch by Nicolas Saenz
Julienne
- Backport two patches from upstream to avoid scheduling ksoftirqd
from a workqueue while completing mmc requests.
- Replace a patch from lockdep series with a suggestion from Peter
Zijlstra.
- Don't acquire dev_base_lock with disabled bottom halves to avoid
lockdep complaint on PREEMPT_RT. Reported by Pei Zhang and Luis
Claudio R. Goncalves.
- Dress a networking patch regarding inet_listen_hashbucket::lock
differently so it looks better.
Known issues
- netconsole triggers WARN.
- The "Memory controller" (CONFIG_MEMCG) has been disabled.
- Valentin Schneider reported a few splats on ARM64, see
https://lkml.kernel.org/r/20210810134127.1394269-1-valentin.schneider@xxxxxxx
The delta patch against v5.16-rc3-rt5 is appended below and can be found here:
https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.16/incr/patch-5.16-rc3-rt5-rt6.patch.xz
You can get this release via the git tree at:
git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git v5.16-rc3-rt6
The RT patch against v5.16-rc3 can be found here:
https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.16/older/patch-5.16-rc3-rt6.patch.xz
The split quilt queue is available at:
https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.16/older/patches-5.16-rc3-rt6.tar.xz
Sebastian
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 6bd4acc2be02f..260866cf53c95 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -89,7 +89,7 @@ config ARM64
select ARCH_SUPPORTS_ATOMIC_RMW
select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
select ARCH_SUPPORTS_NUMA_BALANCING
- select ARCH_SUPPORTS_RT if HAVE_POSIX_CPU_TIMERS_TASK_WORK
+ select ARCH_SUPPORTS_RT
select ARCH_WANT_COMPAT_IPC_PARSE_VERSION if COMPAT
select ARCH_WANT_DEFAULT_BPF_JIT
select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
@@ -216,7 +216,6 @@ config ARM64
select PCI_DOMAINS_GENERIC if PCI
select PCI_ECAM if (ACPI && PCI)
select PCI_SYSCALL if PCI
- select HAVE_POSIX_CPU_TIMERS_TASK_WORK if !KVM
select POWER_RESET
select POWER_SUPPLY
select SPARSE_IRQ
diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index 90e1bcd03b46c..52309b84be888 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -2051,7 +2051,8 @@ static void mmc_blk_mq_dec_in_flight(struct mmc_queue *mq, struct request *req)
mmc_put_card(mq->card, &mq->ctx);
}
-static void mmc_blk_mq_post_req(struct mmc_queue *mq, struct request *req)
+static void mmc_blk_mq_post_req(struct mmc_queue *mq, struct request *req,
+ bool can_sleep)
{
struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
struct mmc_request *mrq = &mqrq->brq.mrq;
@@ -2063,10 +2064,14 @@ static void mmc_blk_mq_post_req(struct mmc_queue *mq, struct request *req)
* Block layer timeouts race with completions which means the normal
* completion path cannot be used during recovery.
*/
- if (mq->in_recovery)
+ if (mq->in_recovery) {
mmc_blk_mq_complete_rq(mq, req);
- else if (likely(!blk_should_fake_timeout(req->q)))
- blk_mq_complete_request(req);
+ } else if (likely(!blk_should_fake_timeout(req->q))) {
+ if (can_sleep)
+ blk_mq_complete_request_direct(req, mmc_blk_mq_complete);
+ else
+ blk_mq_complete_request(req);
+ }
mmc_blk_mq_dec_in_flight(mq, req);
}
@@ -2087,7 +2092,7 @@ void mmc_blk_mq_recovery(struct mmc_queue *mq)
mmc_blk_urgent_bkops(mq, mqrq);
- mmc_blk_mq_post_req(mq, req);
+ mmc_blk_mq_post_req(mq, req, true);
}
static void mmc_blk_mq_complete_prev_req(struct mmc_queue *mq,
@@ -2106,7 +2111,7 @@ static void mmc_blk_mq_complete_prev_req(struct mmc_queue *mq,
if (prev_req)
*prev_req = mq->complete_req;
else
- mmc_blk_mq_post_req(mq, mq->complete_req);
+ mmc_blk_mq_post_req(mq, mq->complete_req, true);
mq->complete_req = NULL;
@@ -2178,7 +2183,8 @@ static void mmc_blk_mq_req_done(struct mmc_request *mrq)
mq->rw_wait = false;
wake_up(&mq->wait);
- mmc_blk_mq_post_req(mq, req);
+ /* context unknown */
+ mmc_blk_mq_post_req(mq, req, false);
}
static bool mmc_blk_rw_wait_cond(struct mmc_queue *mq, int *err)
@@ -2238,7 +2244,7 @@ static int mmc_blk_mq_issue_rw_rq(struct mmc_queue *mq,
err = mmc_start_request(host, &mqrq->brq.mrq);
if (prev_req)
- mmc_blk_mq_post_req(mq, prev_req);
+ mmc_blk_mq_post_req(mq, prev_req, true);
if (err)
mq->rw_wait = false;
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 2949d9ac74849..131b45dfec674 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -752,6 +752,17 @@ static inline void blk_mq_set_request_complete(struct request *rq)
WRITE_ONCE(rq->state, MQ_RQ_COMPLETE);
}
+/*
+ * Complete the request directly instead of deferring it to softirq or
+ * completing it another CPU. Useful in preemptible instead of an interrupt.
+ */
+static inline void blk_mq_complete_request_direct(struct request *rq,
+ void (*complete)(struct request *rq))
+{
+ WRITE_ONCE(rq->state, MQ_RQ_COMPLETE);
+ complete(rq);
+}
+
void blk_mq_start_request(struct request *rq);
void blk_mq_end_request(struct request *rq, blk_status_t error);
void __blk_mq_end_request(struct request *rq, blk_status_t error);
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index 5e19fe7dda4c5..f89620852774d 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1103,27 +1103,12 @@ static int __sched task_blocks_on_rt_mutex(struct rt_mutex_base *lock,
* the other will detect the deadlock and return -EDEADLOCK,
* which is wrong, as the other waiter is not in a deadlock
* situation.
+ *
+ * Except for ww_mutex, in that case the chain walk must already deal
+ * with spurious cycles, see the comments at [3] and [6].
*/
- if (owner == task) {
-#if defined(DEBUG_WW_MUTEXES) && defined(CONFIG_DEBUG_LOCKING_API_SELFTESTS)
- /*
- * The lockdep selftest for ww-mutex assumes in a few cases
- * the ww_ctx->contending_lock assignment via
- * __ww_mutex_check_kill() which does not happen if the rtmutex
- * detects the deadlock early.
- */
- if (build_ww_mutex() && ww_ctx) {
- struct rt_mutex *rtm;
-
- /* Check whether the waiter should backout immediately */
- rtm = container_of(lock, struct rt_mutex, rtmutex);
-
- __ww_mutex_add_waiter(waiter, rtm, ww_ctx);
- __ww_mutex_check_kill(rtm, waiter, ww_ctx);
- }
-#endif
+ if (owner == task && !(build_ww_mutex() && ww_ctx))
return -EDEADLK;
- }
raw_spin_lock(&task->pi_lock);
waiter->task = task;
diff --git a/localversion-rt b/localversion-rt
index 0efe7ba1930e1..8fc605d806670 100644
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt5
+-rt6
diff --git a/net/core/dev.c b/net/core/dev.c
index 8b5cf8ad859b5..ad3cccbfa573b 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -371,12 +371,12 @@ static void list_netdevice(struct net_device *dev)
ASSERT_RTNL();
- write_lock_bh(&dev_base_lock);
+ write_lock(&dev_base_lock);
list_add_tail_rcu(&dev->dev_list, &net->dev_base_head);
netdev_name_node_add(net, dev->name_node);
hlist_add_head_rcu(&dev->index_hlist,
dev_index_hash(net, dev->ifindex));
- write_unlock_bh(&dev_base_lock);
+ write_unlock(&dev_base_lock);
dev_base_seq_inc(net);
}
@@ -389,11 +389,11 @@ static void unlist_netdevice(struct net_device *dev)
ASSERT_RTNL();
/* Unlink dev from the device chain */
- write_lock_bh(&dev_base_lock);
+ write_lock(&dev_base_lock);
list_del_rcu(&dev->dev_list);
netdev_name_node_del(dev->name_node);
hlist_del_rcu(&dev->index_hlist);
- write_unlock_bh(&dev_base_lock);
+ write_unlock(&dev_base_lock);
dev_base_seq_inc(dev_net(dev));
}
@@ -1272,15 +1272,15 @@ int dev_change_name(struct net_device *dev, const char *newname)
netdev_adjacent_rename_links(dev, oldname);
- write_lock_bh(&dev_base_lock);
+ write_lock(&dev_base_lock);
netdev_name_node_del(dev->name_node);
- write_unlock_bh(&dev_base_lock);
+ write_unlock(&dev_base_lock);
synchronize_rcu();
- write_lock_bh(&dev_base_lock);
+ write_lock(&dev_base_lock);
netdev_name_node_add(net, dev->name_node);
- write_unlock_bh(&dev_base_lock);
+ write_unlock(&dev_base_lock);
ret = call_netdevice_notifiers(NETDEV_CHANGENAME, dev);
ret = notifier_to_errno(ret);
diff --git a/net/core/link_watch.c b/net/core/link_watch.c
index 1a455847da54f..9599afd0862da 100644
--- a/net/core/link_watch.c
+++ b/net/core/link_watch.c
@@ -55,7 +55,7 @@ static void rfc2863_policy(struct net_device *dev)
if (operstate == dev->operstate)
return;
- write_lock_bh(&dev_base_lock);
+ write_lock(&dev_base_lock);
switch(dev->link_mode) {
case IF_LINK_MODE_TESTING:
@@ -74,7 +74,7 @@ static void rfc2863_policy(struct net_device *dev)
dev->operstate = operstate;
- write_unlock_bh(&dev_base_lock);
+ write_unlock(&dev_base_lock);
}
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 2af8aeeadadf0..716be2f88cd75 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -842,9 +842,9 @@ static void set_operstate(struct net_device *dev, unsigned char transition)
}
if (dev->operstate != operstate) {
- write_lock_bh(&dev_base_lock);
+ write_lock(&dev_base_lock);
dev->operstate = operstate;
- write_unlock_bh(&dev_base_lock);
+ write_unlock(&dev_base_lock);
netdev_state_change(dev);
}
}
@@ -2779,11 +2779,11 @@ static int do_setlink(const struct sk_buff *skb,
if (tb[IFLA_LINKMODE]) {
unsigned char value = nla_get_u8(tb[IFLA_LINKMODE]);
- write_lock_bh(&dev_base_lock);
+ write_lock(&dev_base_lock);
if (dev->link_mode ^ value)
status |= DO_SETLINK_NOTIFY;
dev->link_mode = value;
- write_unlock_bh(&dev_base_lock);
+ write_unlock(&dev_base_lock);
}
if (tb[IFLA_VFINFO_LIST]) {
diff --git a/net/hsr/hsr_device.c b/net/hsr/hsr_device.c
index 737e4f17e1c6d..e57fdad9ef942 100644
--- a/net/hsr/hsr_device.c
+++ b/net/hsr/hsr_device.c
@@ -30,13 +30,13 @@ static bool is_slave_up(struct net_device *dev)
static void __hsr_set_operstate(struct net_device *dev, int transition)
{
- write_lock_bh(&dev_base_lock);
+ write_lock(&dev_base_lock);
if (dev->operstate != transition) {
dev->operstate = transition;
- write_unlock_bh(&dev_base_lock);
+ write_unlock(&dev_base_lock);
netdev_state_change(dev);
} else {
- write_unlock_bh(&dev_base_lock);
+ write_unlock(&dev_base_lock);
}
}
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index e460c84b1f8e4..7bd1e10086f0a 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -678,41 +678,47 @@ int inet_hash(struct sock *sk)
}
EXPORT_SYMBOL_GPL(inet_hash);
-void inet_unhash(struct sock *sk)
+static void __inet_unhash(struct sock *sk, struct inet_listen_hashbucket *ilb)
{
- struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
- struct inet_listen_hashbucket *ilb = NULL;
- spinlock_t *lock;
- bool state_listen;
-
if (sk_unhashed(sk))
return;
- if (sk->sk_state == TCP_LISTEN) {
- state_listen = true;
- ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
- spin_lock(&ilb->lock);
- } else {
- state_listen = false;
- lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
- spin_lock_bh(lock);
- }
- if (sk_unhashed(sk))
- goto unlock;
-
if (rcu_access_pointer(sk->sk_reuseport_cb))
reuseport_stop_listen_sock(sk);
if (ilb) {
+ struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
+
inet_unhash2(hashinfo, sk);
ilb->count--;
}
__sk_nulls_del_node_init_rcu(sk);
sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
-unlock:
- if (state_listen)
+}
+
+void inet_unhash(struct sock *sk)
+{
+ struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
+
+ if (sk_unhashed(sk))
+ return;
+
+ if (sk->sk_state == TCP_LISTEN) {
+ struct inet_listen_hashbucket *ilb;
+
+ ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
+ /* Don't disable bottom halves while acquiring the lock to
+ * avoid circular locking dependency on PREEMPT_RT.
+ */
+ spin_lock(&ilb->lock);
+ __inet_unhash(sk, ilb);
spin_unlock(&ilb->lock);
- else
+ } else {
+ spinlock_t *lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
+
+ spin_lock_bh(lock);
+ __inet_unhash(sk, NULL);
spin_unlock_bh(lock);
+ }
}
EXPORT_SYMBOL_GPL(inet_unhash);