Someone pointed out (via private email) that a race can still exist
between checking that vt is non-zero and acquiring the semaphore,
especially since we can sleep doing that.
I agree; the following patch should alleviate that race.
diff -u linux-2.4.13-ac5/drivers/char/console.c
linux/drivers/char/console.c
--- linux-2.4.13-ac5/drivers/char/console.c Mon Oct 29 17:27:19 2001
+++ linux/drivers/char/console.c Mon Oct 29 22:11:27 2001
@@ -2387,8 +2387,14 @@
return;
pm_access(pm_con);
+
+ /*
+ * If we raced with con_close(), `vt' may be null.
+ * Hence this bandaid. - akpm
+ */
acquire_console_sem();
- set_cursor(vt->vc_num);
+ if (vt)
+ set_cursor(vt->vc_num);
release_console_sem();
}
Robert Love
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Wed Oct 31 2001 - 21:00:38 EST