The patch titled
uml: fix proc-vs-interrupt context spinlock deadlock
has been added to the -mm tree. Its filename is
uml-fix-proc-vs-interrupt-context-spinlock-deadlock.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: uml: fix proc-vs-interrupt context spinlock deadlock
From: Paolo 'Blaisorblade' Giarrusso <blaisorblade@xxxxxxxx>
This spinlock can be taken on interrupt too, so spin_lock_irq[save] must be
used.
However, Documentation/networking/netdevices.txt explains we are called with
rtnl_lock() held - so we don't need to care about other concurrent opens.
Verified also in LDD3 and by direct checking. Also verified that the network
layer (through a state machine) guarantees us that nobody will close the
interface while it's being used. Please correct me if I'm wrong.
Also, we must check we don't sleep with irqs disabled!!! But anyway, this is
not news - we already can't sleep while holding a spinlock. Who says this is
guaranted really by the present code?
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@xxxxxxxx>
Cc: Jeff Dike <jdike@xxxxxxxxxxx>
Cc: Jeff Garzik <jeff@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
diff -puN arch/um/drivers/net_kern.c~uml-fix-proc-vs-interrupt-context-spinlock-deadlock arch/um/drivers/net_kern.c
--- a/arch/um/drivers/net_kern.c~uml-fix-proc-vs-interrupt-context-spinlock-deadlock
+++ a/arch/um/drivers/net_kern.c
@@ -109,8 +109,6 @@ static int uml_net_open(struct net_devic
struct uml_net_private *lp = dev->priv;
int err;
- spin_lock(&lp->lock);
-
if(lp->fd >= 0){
err = -ENXIO;
goto out;
@@ -144,8 +142,6 @@ static int uml_net_open(struct net_devic
*/
while((err = uml_net_rx(dev)) > 0) ;
- spin_unlock(&lp->lock);
-
spin_lock(&opened_lock);
list_add(&lp->list, &opened);
spin_unlock(&opened_lock);
@@ -155,7 +151,6 @@ out_close:
if(lp->close != NULL) (*lp->close)(lp->fd, &lp->user);
lp->fd = -1;
out:
- spin_unlock(&lp->lock);
return err;
}
@@ -164,15 +159,12 @@ static int uml_net_close(struct net_devi
struct uml_net_private *lp = dev->priv;
netif_stop_queue(dev);
- spin_lock(&lp->lock);
free_irq(dev->irq, dev);
if(lp->close != NULL)
(*lp->close)(lp->fd, &lp->user);
lp->fd = -1;
- spin_unlock(&lp->lock);
-
spin_lock(&opened_lock);
list_del(&lp->list);
spin_unlock(&opened_lock);
@@ -241,9 +233,9 @@ static int uml_net_set_mac(struct net_de
struct uml_net_private *lp = dev->priv;
struct sockaddr *hwaddr = addr;
- spin_lock(&lp->lock);
+ spin_lock_irq(&lp->lock);
memcpy(dev->dev_addr, hwaddr->sa_data, ETH_ALEN);
- spin_unlock(&lp->lock);
+ spin_unlock_irq(&lp->lock);
return(0);
}
@@ -253,7 +245,7 @@ static int uml_net_change_mtu(struct net
struct uml_net_private *lp = dev->priv;
int err = 0;
- spin_lock(&lp->lock);
+ spin_lock_irq(&lp->lock);
new_mtu = (*lp->set_mtu)(new_mtu, &lp->user);
if(new_mtu < 0){
@@ -264,7 +256,7 @@ static int uml_net_change_mtu(struct net
dev->mtu = new_mtu;
out:
- spin_unlock(&lp->lock);
+ spin_unlock_irq(&lp->lock);
return err;
}
_
Patches currently in -mm which might be from blaisorblade@xxxxxxxx are
uml-use-mcmodel=kernel-for-x86_64.patch
uml-fix-proc-vs-interrupt-context-spinlock-deadlock.patch
uml-clean-our-set_ether_mac.patch
uml-remove-pte_mkexec.patch
-
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