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authorRalf Baechle <ralf@linux-mips.org>2009-07-12 21:09:20 -0700
committerDavid S. Miller <davem@davemloft.net>2009-07-12 21:09:20 -0700
commitadeab1afb7de89555c69aab5ca21300c14af6369 (patch)
tree9e300563895b33a75876be58f167006fa8cbde3d /drivers/net/hamradio
parent635ecaa70e862f85f652581305fe0074810893be (diff)
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NET: Fix locking issues in PPP, 6pack, mkiss and strip line disciplines.
Guido Trentalancia reports: I am trying to use the kiss driver in the Linux kernel that is being shipped with Fedora 10 but unfortunately I get the following oops: mkiss: AX.25 Multikiss, Hans Albas PE1AYX mkiss: ax0: crc mode is auto. ADDRCONF(NETDEV_CHANGE): ax0: link becomes ready ------------[ cut here ]------------ WARNING: at kernel/softirq.c:77 __local_bh_disable+0x2f/0x83() (Not tainted) [...] unloaded: microcode] Pid: 0, comm: swapper Not tainted 2.6.27.25-170.2.72.fc10.i686 #1 [<c042ddfb>] warn_on_slowpath+0x65/0x8b [<c06ab62b>] ? _spin_unlock_irqrestore+0x22/0x38 [<c04228b4>] ? __enqueue_entity+0xe3/0xeb [<c042431e>] ? enqueue_entity+0x203/0x20b [<c0424361>] ? enqueue_task_fair+0x3b/0x3f [<c041f88c>] ? resched_task+0x3a/0x6e [<c06ab62b>] ? _spin_unlock_irqrestore+0x22/0x38 [<c06ab4e2>] ? _spin_lock_bh+0xb/0x16 [<c043255b>] __local_bh_disable+0x2f/0x83 [<c04325ba>] local_bh_disable+0xb/0xd [<c06ab4e2>] _spin_lock_bh+0xb/0x16 [<f8b6f600>] mkiss_receive_buf+0x2fb/0x3a6 [mkiss] [<c0572a30>] flush_to_ldisc+0xf7/0x198 [<c0572b12>] tty_flip_buffer_push+0x41/0x51 [<f89477f2>] ftdi_process_read+0x375/0x4ad [ftdi_sio] [<f8947a5a>] ftdi_read_bulk_callback+0x130/0x138 [ftdi_sio] [<c05d4bec>] usb_hcd_giveback_urb+0x63/0x93 [<c05ea290>] uhci_giveback_urb+0xe5/0x15f [<c05eaabf>] uhci_scan_schedule+0x52e/0x767 [<c05f6288>] ? psmouse_handle_byte+0xc/0xe5 [<c054df78>] ? acpi_ev_gpe_detect+0xd6/0xe1 [<c05ec5b0>] uhci_irq+0x110/0x125 [<c05d4834>] usb_hcd_irq+0x40/0xa3 [<c0465313>] handle_IRQ_event+0x2f/0x64 [<c046642b>] handle_level_irq+0x74/0xbe [<c04663b7>] ? handle_level_irq+0x0/0xbe [<c0406e6e>] do_IRQ+0xc7/0xfe [<c0405668>] common_interrupt+0x28/0x30 [<c056821a>] ? acpi_idle_enter_simple+0x162/0x19d [<c0617f52>] cpuidle_idle_call+0x60/0x92 [<c0403c61>] cpu_idle+0x101/0x134 [<c069b1ba>] rest_init+0x4e/0x50 ======================= ---[ end trace b7cc8076093467ad ]--- ------------[ cut here ]------------ WARNING: at kernel/softirq.c:136 _local_bh_enable_ip+0x3d/0xc4() [...] Pid: 0, comm: swapper Tainted: G W 2.6.27.25-170.2.72.fc10.i686 [<c042ddfb>] warn_on_slowpath+0x65/0x8b [<c06ab62b>] ? _spin_unlock_irqrestore+0x22/0x38 [<c04228b4>] ? __enqueue_entity+0xe3/0xeb [<c042431e>] ? enqueue_entity+0x203/0x20b [<c0424361>] ? enqueue_task_fair+0x3b/0x3f [<c041f88c>] ? resched_task+0x3a/0x6e [<c06ab62b>] ? _spin_unlock_irqrestore+0x22/0x38 [<c06ab4e2>] ? _spin_lock_bh+0xb/0x16 [<f8b6f642>] ? mkiss_receive_buf+0x33d/0x3a6 [mkiss] [<c04325f9>] _local_bh_enable_ip+0x3d/0xc4 [<c0432688>] local_bh_enable_ip+0x8/0xa [<c06ab54d>] _spin_unlock_bh+0x11/0x13 [<f8b6f642>] mkiss_receive_buf+0x33d/0x3a6 [mkiss] [<c0572a30>] flush_to_ldisc+0xf7/0x198 [<c0572b12>] tty_flip_buffer_push+0x41/0x51 [<f89477f2>] ftdi_process_read+0x375/0x4ad [ftdi_sio] [<f8947a5a>] ftdi_read_bulk_callback+0x130/0x138 [ftdi_sio] [<c05d4bec>] usb_hcd_giveback_urb+0x63/0x93 [<c05ea290>] uhci_giveback_urb+0xe5/0x15f [<c05eaabf>] uhci_scan_schedule+0x52e/0x767 [<c05f6288>] ? psmouse_handle_byte+0xc/0xe5 [<c054df78>] ? acpi_ev_gpe_detect+0xd6/0xe1 [<c05ec5b0>] uhci_irq+0x110/0x125 [<c05d4834>] usb_hcd_irq+0x40/0xa3 [<c0465313>] handle_IRQ_event+0x2f/0x64 [<c046642b>] handle_level_irq+0x74/0xbe [<c04663b7>] ? handle_level_irq+0x0/0xbe [<c0406e6e>] do_IRQ+0xc7/0xfe [<c0405668>] common_interrupt+0x28/0x30 [<c056821a>] ? acpi_idle_enter_simple+0x162/0x19d [<c0617f52>] cpuidle_idle_call+0x60/0x92 [<c0403c61>] cpu_idle+0x101/0x134 [<c069b1ba>] rest_init+0x4e/0x50 ======================= ---[ end trace b7cc8076093467ad ]--- mkiss: ax0: Trying crc-smack mkiss: ax0: Trying crc-flexnet The issue was, that the locking code in mkiss was assuming it was only ever being called in process or bh context. Fixed by converting the involved locking code to use irq-safe locks. Review of other networking line disciplines shows that 6pack, both sync and async PPP and STRIP have similar issues. The ppp_async one is the most interesting one as it sorts out half of the issue as far back as 2004 in commit http://git.kernel.org/?p=linux/kernel/git/tglx/history.git;a=commitdiff;h=2996d8deaeddd01820691a872550dc0cfba0c37d Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Reported-by: Guido Trentalancia <guido@trentalancia.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/hamradio')
-rw-r--r--drivers/net/hamradio/6pack.c10
-rw-r--r--drivers/net/hamradio/mkiss.c41
2 files changed, 30 insertions, 21 deletions
diff --git a/drivers/net/hamradio/6pack.c b/drivers/net/hamradio/6pack.c
index 1551600..913a564 100644
--- a/drivers/net/hamradio/6pack.c
+++ b/drivers/net/hamradio/6pack.c
@@ -398,13 +398,14 @@ static DEFINE_RWLOCK(disc_data_lock);
static struct sixpack *sp_get(struct tty_struct *tty)
{
+ unsigned long flags;
struct sixpack *sp;
- read_lock(&disc_data_lock);
+ read_lock_irqsave(&disc_data_lock, flags);
sp = tty->disc_data;
if (sp)
atomic_inc(&sp->refcnt);
- read_unlock(&disc_data_lock);
+ read_unlock_irqrestore(&disc_data_lock, flags);
return sp;
}
@@ -688,12 +689,13 @@ out:
*/
static void sixpack_close(struct tty_struct *tty)
{
+ unsigned long flags;
struct sixpack *sp;
- write_lock(&disc_data_lock);
+ write_lock_irqsave(&disc_data_lock, flags);
sp = tty->disc_data;
tty->disc_data = NULL;
- write_unlock(&disc_data_lock);
+ write_unlock_irqrestore(&disc_data_lock, flags);
if (!sp)
return;
diff --git a/drivers/net/hamradio/mkiss.c b/drivers/net/hamradio/mkiss.c
index fda2fc8..a728650 100644
--- a/drivers/net/hamradio/mkiss.c
+++ b/drivers/net/hamradio/mkiss.c
@@ -244,15 +244,16 @@ static int kiss_esc_crc(unsigned char *s, unsigned char *d, unsigned short crc,
/* Send one completely decapsulated AX.25 packet to the AX.25 layer. */
static void ax_bump(struct mkiss *ax)
{
+ unsigned long flags;
struct sk_buff *skb;
int count;
- spin_lock_bh(&ax->buflock);
+ spin_lock_irqsave(&ax->buflock, flags);
if (ax->rbuff[0] > 0x0f) {
if (ax->rbuff[0] & 0x80) {
if (check_crc_16(ax->rbuff, ax->rcount) < 0) {
ax->dev->stats.rx_errors++;
- spin_unlock_bh(&ax->buflock);
+ spin_unlock_irqrestore(&ax->buflock, flags);
return;
}
@@ -267,7 +268,7 @@ static void ax_bump(struct mkiss *ax)
} else if (ax->rbuff[0] & 0x20) {
if (check_crc_flex(ax->rbuff, ax->rcount) < 0) {
ax->dev->stats.rx_errors++;
- spin_unlock_bh(&ax->buflock);
+ spin_unlock_irqrestore(&ax->buflock, flags);
return;
}
if (ax->crcmode != CRC_MODE_FLEX && ax->crcauto) {
@@ -294,7 +295,7 @@ static void ax_bump(struct mkiss *ax)
printk(KERN_ERR "mkiss: %s: memory squeeze, dropping packet.\n",
ax->dev->name);
ax->dev->stats.rx_dropped++;
- spin_unlock_bh(&ax->buflock);
+ spin_unlock_irqrestore(&ax->buflock, flags);
return;
}
@@ -303,11 +304,13 @@ static void ax_bump(struct mkiss *ax)
netif_rx(skb);
ax->dev->stats.rx_packets++;
ax->dev->stats.rx_bytes += count;
- spin_unlock_bh(&ax->buflock);
+ spin_unlock_irqrestore(&ax->buflock, flags);
}
static void kiss_unesc(struct mkiss *ax, unsigned char s)
{
+ unsigned long flags;
+
switch (s) {
case END:
/* drop keeptest bit = VSV */
@@ -334,18 +337,18 @@ static void kiss_unesc(struct mkiss *ax, unsigned char s)
break;
}
- spin_lock_bh(&ax->buflock);
+ spin_lock_irqsave(&ax->buflock, flags);
if (!test_bit(AXF_ERROR, &ax->flags)) {
if (ax->rcount < ax->buffsize) {
ax->rbuff[ax->rcount++] = s;
- spin_unlock_bh(&ax->buflock);
+ spin_unlock_irqrestore(&ax->buflock, flags);
return;
}
ax->dev->stats.rx_over_errors++;
set_bit(AXF_ERROR, &ax->flags);
}
- spin_unlock_bh(&ax->buflock);
+ spin_unlock_irqrestore(&ax->buflock, flags);
}
static int ax_set_mac_address(struct net_device *dev, void *addr)
@@ -367,6 +370,7 @@ static void ax_changedmtu(struct mkiss *ax)
{
struct net_device *dev = ax->dev;
unsigned char *xbuff, *rbuff, *oxbuff, *orbuff;
+ unsigned long flags;
int len;
len = dev->mtu * 2;
@@ -392,7 +396,7 @@ static void ax_changedmtu(struct mkiss *ax)
return;
}
- spin_lock_bh(&ax->buflock);
+ spin_lock_irqsave(&ax->buflock, flags);
oxbuff = ax->xbuff;
ax->xbuff = xbuff;
@@ -423,7 +427,7 @@ static void ax_changedmtu(struct mkiss *ax)
ax->mtu = dev->mtu + 73;
ax->buffsize = len;
- spin_unlock_bh(&ax->buflock);
+ spin_unlock_irqrestore(&ax->buflock, flags);
kfree(oxbuff);
kfree(orbuff);
@@ -433,6 +437,7 @@ static void ax_changedmtu(struct mkiss *ax)
static void ax_encaps(struct net_device *dev, unsigned char *icp, int len)
{
struct mkiss *ax = netdev_priv(dev);
+ unsigned long flags;
unsigned char *p;
int actual, count;
@@ -449,7 +454,7 @@ static void ax_encaps(struct net_device *dev, unsigned char *icp, int len)
p = icp;
- spin_lock_bh(&ax->buflock);
+ spin_lock_irqsave(&ax->buflock, flags);
if ((*p & 0x0f) != 0) {
/* Configuration Command (kissparms(1).
* Protocol spec says: never append CRC.
@@ -479,7 +484,7 @@ static void ax_encaps(struct net_device *dev, unsigned char *icp, int len)
ax->crcauto = (cmd ? 0 : 1);
printk(KERN_INFO "mkiss: %s: crc mode %s %d\n", ax->dev->name, (len) ? "set to" : "is", cmd);
}
- spin_unlock_bh(&ax->buflock);
+ spin_unlock_irqrestore(&ax->buflock, flags);
netif_start_queue(dev);
return;
@@ -512,7 +517,7 @@ static void ax_encaps(struct net_device *dev, unsigned char *icp, int len)
count = kiss_esc(p, (unsigned char *)ax->xbuff, len);
}
}
- spin_unlock_bh(&ax->buflock);
+ spin_unlock_irqrestore(&ax->buflock, flags);
set_bit(TTY_DO_WRITE_WAKEUP, &ax->tty->flags);
actual = ax->tty->ops->write(ax->tty, ax->xbuff, count);
@@ -704,13 +709,14 @@ static DEFINE_RWLOCK(disc_data_lock);
static struct mkiss *mkiss_get(struct tty_struct *tty)
{
+ unsigned long flags;
struct mkiss *ax;
- read_lock(&disc_data_lock);
+ read_lock_irqsave(&disc_data_lock, flags);
ax = tty->disc_data;
if (ax)
atomic_inc(&ax->refcnt);
- read_unlock(&disc_data_lock);
+ read_unlock_irqrestore(&disc_data_lock, flags);
return ax;
}
@@ -809,12 +815,13 @@ out:
static void mkiss_close(struct tty_struct *tty)
{
+ unsigned long flags;
struct mkiss *ax;
- write_lock(&disc_data_lock);
+ write_lock_irqsave(&disc_data_lock, flags);
ax = tty->disc_data;
tty->disc_data = NULL;
- write_unlock(&disc_data_lock);
+ write_unlock_irqrestore(&disc_data_lock, flags);
if (!ax)
return;