> Trace: c48222c2 <isdn_tty_edit_at+42/16c>
> Trace: c481ea11 <isdn_tty_write+2e5/338>
Good job, isdn_tty_write() was not yet known to be a potential "Ugh" source.
Maybe, it is not really necessary to turn off interrupts in isdn_tty_write
(this requires some deeper analysis). Did you only observe "Ugh" messages
or additionally some other spourious behavior while or after the "Ugh"
appeared?
Anyway, the follwowing patch (quick and dirty, the additional copying will
have some performance impact when writing to isdn ttys) should help for now.
Henner
--- 2.1.103-i4ldev/drivers/isdn/isdn_tty.c Tue Mar 24 00:24:27 1998
+++ 2.1.103-ix25/drivers/isdn/isdn_tty.c Thu Jun 4 23:11:32 1998
@@ -1294,6 +1294,7 @@
{
int c;
int total = 0;
+ u_char * tmp = NULL;
ulong flags;
modem_info *info = (modem_info *) tty->driver_data;
@@ -1301,6 +1302,15 @@
return 0;
if (!tty)
return 0;
+ /* brute force method to fix user space access with interrupts off */
+ if(from_user) {
+ tmp = kmalloc(count,GFP_KERNEL);
+ if ( ! tmp ) return -ENOMEM;
+ if( copy_from_user(tmp,buf,count) ) return -EFAULT;
+ buf = tmp;
+ from_user = 0;
+ }
+ /* however, is turning of interrupts really necessary ? */
save_flags(flags);
cli();
while (1) {
@@ -1385,6 +1395,7 @@
if ((info->xmit_count) || (skb_queue_len(&info->xmit_queue)))
isdn_timer_ctrl(ISDN_TIMER_MODEMXMIT, 1);
restore_flags(flags);
+ if( tmp ) kfree(tmp);
return total;
}
-
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