Linus,
There is a race between con_flush_chars and con_close. I first
discovered it with the preemptive kernel patch, but it is a general SMP
race. The idea for the fix is originally by Andrew Morton.
This fix is in 2.4. Please, apply.
Robert Love
diff -urN linux-2.5.3-pre5/drivers/char/console.c linux/drivers/char/console.c
--- linux-2.5.3-pre5/drivers/char/console.c Thu Jan 24 17:02:57 2002
+++ linux/drivers/char/console.c Fri Jan 25 18:12:36 2002
@@ -2349,14 +2349,18 @@
static void con_flush_chars(struct tty_struct *tty)
{
- struct vt_struct *vt = (struct vt_struct *)tty->driver_data;
+ struct vt_struct *vt;
if (in_interrupt()) /* from flush_to_ldisc */
return;
pm_access(pm_con);
+
+ /* if we race with con_close(), vt may be null */
acquire_console_sem();
- set_cursor(vt->vc_num);
+ vt = (struct vt_struct *)tty->driver_data;
+ if (vt)
+ set_cursor(vt->vc_num);
release_console_sem();
}
-
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This archive was generated by hypermail 2b29 : Thu Jan 31 2002 - 21:00:37 EST