[PATCH] console close race fix resend

From: Robert Love (rml@tech9.net)
Date: Mon Dec 10 2001 - 20:51:51 EST


[ Resend of previous patch, now against pre8. Note it (a) is a bug fix
and (b) was in Alan's tree ]

The attached is a fix originally by Andrew Morton and discovered by the
preempt-kernel patch. It is in Alan's tree but was never merged into

There is a race between con_close and con_flush_chars.
n_tty_receive_buf writes to the tty queue and then flushes it via
con_flush_chars. If the console closes in between these operations,
con_flush_char barfs.

Please, for all that is righteous, apply.

        Robert Love

diff -urN linux-2.4.17-pre8/drivers/char/console.c linux/drivers/char/console.c
--- linux-2.4.17-pre8/drivers/char/console.c Thu Dec 6 14:08:14 2001
+++ linux/drivers/char/console.c Thu Dec 6 14:09:06 2001
@@ -2356,8 +2356,14 @@
+ /*
+ * If we raced with con_close(), `vt' may be null.
+ * Hence this bandaid. - akpm
+ */
- set_cursor(vt->vc_num);
+ if (vt)
+ set_cursor(vt->vc_num);

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This archive was generated by hypermail 2b29 : Sat Dec 15 2001 - 21:00:19 EST