4.4-stable patches

added patches:
	x86-i8259-use-printk_deferred-to-prevent-deadlock.patch

diff --git a/queue-4.4/series b/queue-4.4/series
index 220a53e55340388dc35aad88d8f6bfb74ad9d70b..fe1c10783f67d2c2c5865d4822304c9f89296c31 100644 (file)
--- a/queue-4.4/series
+++ b/queue-4.4/series
@@ -29,3 +29,4 @@ nfc-s3fwrn5-add-missing-release-on-skb-in-s3fwrn5_re.patch
 net-ethernet-ravb-exit-if-re-initialization-fails-in.patch
 revert-i2c-cadence-fix-the-hold-bit-setting.patch
 xen-netfront-fix-potential-deadlock-in-xennet_remove.patch
+x86-i8259-use-printk_deferred-to-prevent-deadlock.patch

diff --git a/queue-4.4/x86-i8259-use-printk_deferred-to-prevent-deadlock.patch b/queue-4.4/x86-i8259-use-printk_deferred-to-prevent-deadlock.patch
new file mode 100644 (file)
index 0000000..fd41b78
--- /dev/null
+++ b/queue-4.4/x86-i8259-use-printk_deferred-to-prevent-deadlock.patch
@@ -0,0 +1,51 @@
+From bdd65589593edd79b6a12ce86b3b7a7c6dae5208 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Wed, 29 Jul 2020 10:53:28 +0200
+Subject: x86/i8259: Use printk_deferred() to prevent deadlock
+
+From: Thomas Gleixner <tglx@linutronix.de>
+
+commit bdd65589593edd79b6a12ce86b3b7a7c6dae5208 upstream.
+
+0day reported a possible circular locking dependency:
+
+Chain exists of:
+  &irq_desc_lock_class --> console_owner --> &port_lock_key
+
+ Possible unsafe locking scenario:
+
+       CPU0                    CPU1
+       ----                    ----
+  lock(&port_lock_key);
+                               lock(console_owner);
+                               lock(&port_lock_key);
+  lock(&irq_desc_lock_class);
+
+The reason for this is a printk() in the i8259 interrupt chip driver
+which is invoked with the irq descriptor lock held, which reverses the
+lock operations vs. printk() from arbitrary contexts.
+
+Switch the printk() to printk_deferred() to avoid that.
+
+Reported-by: kernel test robot <lkp@intel.com>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Ingo Molnar <mingo@kernel.org>
+Cc: stable@vger.kernel.org
+Link: https://lore.kernel.org/r/87365abt2v.fsf@nanos.tec.linutronix.de
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ arch/x86/kernel/i8259.c |    2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+--- a/arch/x86/kernel/i8259.c
++++ b/arch/x86/kernel/i8259.c
+@@ -204,7 +204,7 @@ spurious_8259A_irq:
+                * lets ACK and report it. [once per IRQ]
+                */
+               if (!(spurious_irq_mask & irqmask)) {
+-                      printk(KERN_DEBUG
++                      printk_deferred(KERN_DEBUG
+                              "spurious 8259A interrupt: IRQ%d.\n", irq);
+                       spurious_irq_mask |= irqmask;
+               }

diff --git a/queue-4.4/xen-netfront-fix-potential-deadlock-in-xennet_remove.patch b/queue-4.4/xen-netfront-fix-potential-deadlock-in-xennet_remove.patch
index 4f236deed5e07dd3a35f92f60aabd327cfd45bec..7233e0f757ed6e887a4efd1d04759e7800626fa3 100644 (file)
--- a/queue-4.4/xen-netfront-fix-potential-deadlock-in-xennet_remove.patch
+++ b/queue-4.4/xen-netfront-fix-potential-deadlock-in-xennet_remove.patch
@@ -31,14 +31,12 @@ Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
 Signed-off-by: David S. Miller <davem@davemloft.net>
 Signed-off-by: Sasha Levin <sashal@kernel.org>
 ---
- drivers/net/xen-netfront.c | 64 +++++++++++++++++++++++++-------------
+ drivers/net/xen-netfront.c |   64 +++++++++++++++++++++++++++++----------------
  1 file changed, 42 insertions(+), 22 deletions(-)
 
-diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
-index 02b6a6c108400..7d4c0c46a889d 100644
 --- a/drivers/net/xen-netfront.c
 +++ b/drivers/net/xen-netfront.c
-@@ -62,6 +62,8 @@ module_param_named(max_queues, xennet_max_queues, uint, 0644);
+@@ -62,6 +62,8 @@ module_param_named(max_queues, xennet_ma
  MODULE_PARM_DESC(max_queues,
                 "Maximum number of queues per virtual interface");
  
@@ -47,7 +45,7 @@ index 02b6a6c108400..7d4c0c46a889d 100644
  static const struct ethtool_ops xennet_ethtool_ops;
  
  struct netfront_cb {
-@@ -1349,12 +1351,15 @@ static struct net_device *xennet_create_dev(struct xenbus_device *dev)
+@@ -1349,12 +1351,15 @@ static struct net_device *xennet_create_
  
        netif_carrier_off(netdev);
  
@@ -69,7 +67,7 @@ index 02b6a6c108400..7d4c0c46a889d 100644
        return netdev;
  
   exit:
-@@ -2166,28 +2171,43 @@ static const struct attribute_group xennet_dev_group = {
+@@ -2166,28 +2171,43 @@ static const struct attribute_group xenn
  };
  #endif /* CONFIG_SYSFS */
  
@@ -100,10 +98,10 @@ index 02b6a6c108400..7d4c0c46a889d 100644
 +                                 XenbusStateUnknown,
 +                                 XENNET_TIMEOUT);
 +      } while (!ret);
-+
+ 
 +      if (xenbus_read_driver_state(dev->otherend) == XenbusStateClosed)
 +              return;
- 
++
 +      do {
                xenbus_switch_state(dev, XenbusStateClosed);
 -              wait_event(module_wq,
@@ -129,6 +127,3 @@ index 02b6a6c108400..7d4c0c46a889d 100644
        xennet_disconnect_backend(info);
  
        if (info->netdev->reg_state == NETREG_REGISTERED)
--- 
-2.25.1
-