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-rw-r--r--drivers/isdn/capi/capi.c35
1 files changed, 35 insertions, 0 deletions
diff --git a/drivers/isdn/capi/capi.c b/drivers/isdn/capi/capi.c
index 38045910ca94..9e48bb5a3c09 100644
--- a/drivers/isdn/capi/capi.c
+++ b/drivers/isdn/capi/capi.c
@@ -118,6 +118,15 @@ struct capiminor {
};
#endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */
+/* FIXME: The following lock is a sledgehammer-workaround to a
+ * locking issue with the capiminor (and maybe other) data structure(s).
+ * Access to this data is done in a racy way and crashes the machine with
+ * a FritzCard DSL driver; sooner or later. This is a workaround
+ * which trades scalability vs stability, so it doesn't crash the kernel anymore.
+ * The correct (and scalable) fix for the issue seems to require
+ * an API change to the drivers... . */
+static DEFINE_SPINLOCK(workaround_lock);
+
struct capincci {
struct capincci *next;
u32 ncci;
@@ -589,6 +598,7 @@ static void capi_recv_message(struct capi20_appl *ap, struct sk_buff *skb)
#endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */
struct capincci *np;
u32 ncci;
+ unsigned long flags;
if (CAPIMSG_CMD(skb->data) == CAPI_CONNECT_B3_CONF) {
u16 info = CAPIMSG_U16(skb->data, 12); // Info field
@@ -603,9 +613,11 @@ static void capi_recv_message(struct capi20_appl *ap, struct sk_buff *skb)
capincci_alloc(cdev, CAPIMSG_NCCI(skb->data));
up(&cdev->ncci_list_sem);
}
+ spin_lock_irqsave(&workaround_lock, flags);
if (CAPIMSG_COMMAND(skb->data) != CAPI_DATA_B3) {
skb_queue_tail(&cdev->recvqueue, skb);
wake_up_interruptible(&cdev->recvwait);
+ spin_unlock_irqrestore(&workaround_lock, flags);
return;
}
ncci = CAPIMSG_CONTROL(skb->data);
@@ -615,6 +627,7 @@ static void capi_recv_message(struct capi20_appl *ap, struct sk_buff *skb)
printk(KERN_ERR "BUG: capi_signal: ncci not found\n");
skb_queue_tail(&cdev->recvqueue, skb);
wake_up_interruptible(&cdev->recvwait);
+ spin_unlock_irqrestore(&workaround_lock, flags);
return;
}
#ifndef CONFIG_ISDN_CAPI_MIDDLEWARE
@@ -625,6 +638,7 @@ static void capi_recv_message(struct capi20_appl *ap, struct sk_buff *skb)
if (!mp) {
skb_queue_tail(&cdev->recvqueue, skb);
wake_up_interruptible(&cdev->recvwait);
+ spin_unlock_irqrestore(&workaround_lock, flags);
return;
}
@@ -660,6 +674,7 @@ static void capi_recv_message(struct capi20_appl *ap, struct sk_buff *skb)
wake_up_interruptible(&cdev->recvwait);
}
#endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */
+ spin_unlock_irqrestore(&workaround_lock, flags);
}
/* -------- file_operations for capidev ----------------------------- */
@@ -1006,6 +1021,7 @@ static struct file_operations capi_fops =
static int capinc_tty_open(struct tty_struct * tty, struct file * file)
{
struct capiminor *mp;
+ unsigned long flags;
if ((mp = capiminor_find(iminor(file->f_path.dentry->d_inode))) == 0)
return -ENXIO;
@@ -1014,6 +1030,7 @@ static int capinc_tty_open(struct tty_struct * tty, struct file * file)
tty->driver_data = (void *)mp;
+ spin_lock_irqsave(&workaround_lock, flags);
if (atomic_read(&mp->ttyopencount) == 0)
mp->tty = tty;
atomic_inc(&mp->ttyopencount);
@@ -1021,6 +1038,7 @@ static int capinc_tty_open(struct tty_struct * tty, struct file * file)
printk(KERN_DEBUG "capinc_tty_open ocount=%d\n", atomic_read(&mp->ttyopencount));
#endif
handle_minor_recv(mp);
+ spin_unlock_irqrestore(&workaround_lock, flags);
return 0;
}
@@ -1054,6 +1072,7 @@ static int capinc_tty_write(struct tty_struct * tty,
{
struct capiminor *mp = (struct capiminor *)tty->driver_data;
struct sk_buff *skb;
+ unsigned long flags;
#ifdef _DEBUG_TTYFUNCS
printk(KERN_DEBUG "capinc_tty_write(count=%d)\n", count);
@@ -1066,6 +1085,7 @@ static int capinc_tty_write(struct tty_struct * tty,
return 0;
}
+ spin_lock_irqsave(&workaround_lock, flags);
skb = mp->ttyskb;
if (skb) {
mp->ttyskb = NULL;
@@ -1076,6 +1096,7 @@ static int capinc_tty_write(struct tty_struct * tty,
skb = alloc_skb(CAPI_DATA_B3_REQ_LEN+count, GFP_ATOMIC);
if (!skb) {
printk(KERN_ERR "capinc_tty_write: alloc_skb failed\n");
+ spin_unlock_irqrestore(&workaround_lock, flags);
return -ENOMEM;
}
@@ -1086,6 +1107,7 @@ static int capinc_tty_write(struct tty_struct * tty,
mp->outbytes += skb->len;
(void)handle_minor_send(mp);
(void)handle_minor_recv(mp);
+ spin_unlock_irqrestore(&workaround_lock, flags);
return count;
}
@@ -1093,6 +1115,7 @@ static void capinc_tty_put_char(struct tty_struct *tty, unsigned char ch)
{
struct capiminor *mp = (struct capiminor *)tty->driver_data;
struct sk_buff *skb;
+ unsigned long flags;
#ifdef _DEBUG_TTYFUNCS
printk(KERN_DEBUG "capinc_put_char(%u)\n", ch);
@@ -1105,10 +1128,12 @@ static void capinc_tty_put_char(struct tty_struct *tty, unsigned char ch)
return;
}
+ spin_lock_irqsave(&workaround_lock, flags);
skb = mp->ttyskb;
if (skb) {
if (skb_tailroom(skb) > 0) {
*(skb_put(skb, 1)) = ch;
+ spin_unlock_irqrestore(&workaround_lock, flags);
return;
}
mp->ttyskb = NULL;
@@ -1124,12 +1149,14 @@ static void capinc_tty_put_char(struct tty_struct *tty, unsigned char ch)
} else {
printk(KERN_ERR "capinc_put_char: char %u lost\n", ch);
}
+ spin_unlock_irqrestore(&workaround_lock, flags);
}
static void capinc_tty_flush_chars(struct tty_struct *tty)
{
struct capiminor *mp = (struct capiminor *)tty->driver_data;
struct sk_buff *skb;
+ unsigned long flags;
#ifdef _DEBUG_TTYFUNCS
printk(KERN_DEBUG "capinc_tty_flush_chars\n");
@@ -1142,6 +1169,7 @@ static void capinc_tty_flush_chars(struct tty_struct *tty)
return;
}
+ spin_lock_irqsave(&workaround_lock, flags);
skb = mp->ttyskb;
if (skb) {
mp->ttyskb = NULL;
@@ -1150,6 +1178,7 @@ static void capinc_tty_flush_chars(struct tty_struct *tty)
(void)handle_minor_send(mp);
}
(void)handle_minor_recv(mp);
+ spin_unlock_irqrestore(&workaround_lock, flags);
}
static int capinc_tty_write_room(struct tty_struct *tty)
@@ -1220,12 +1249,15 @@ static void capinc_tty_throttle(struct tty_struct * tty)
static void capinc_tty_unthrottle(struct tty_struct * tty)
{
struct capiminor *mp = (struct capiminor *)tty->driver_data;
+ unsigned long flags;
#ifdef _DEBUG_TTYFUNCS
printk(KERN_DEBUG "capinc_tty_unthrottle\n");
#endif
if (mp) {
+ spin_lock_irqsave(&workaround_lock, flags);
mp->ttyinstop = 0;
handle_minor_recv(mp);
+ spin_unlock_irqrestore(&workaround_lock, flags);
}
}
@@ -1243,12 +1275,15 @@ static void capinc_tty_stop(struct tty_struct *tty)
static void capinc_tty_start(struct tty_struct *tty)
{
struct capiminor *mp = (struct capiminor *)tty->driver_data;
+ unsigned long flags;
#ifdef _DEBUG_TTYFUNCS
printk(KERN_DEBUG "capinc_tty_start\n");
#endif
if (mp) {
+ spin_lock_irqsave(&workaround_lock, flags);
mp->ttyoutstop = 0;
(void)handle_minor_send(mp);
+ spin_unlock_irqrestore(&workaround_lock, flags);
}
}
generated by cgit v1.2.3-55-g7522 (git 2.39.0) at 2024-11-01 22:41:14 +0100