From: Robert Love <rml@tech9.net>
To: marcelo@conectiva.com.br
Cc: gordo@pincoya.com, linux-kernel@vger.kernel.org,
Andrew Morton <akpm@zip.com.au>
Subject: [PATCH] Re: console close race fix resend
Date: 11 Dec 2001 04:05:30 -0500 [thread overview]
Message-ID: <1008061551.815.1.camel@phantasy> (raw)
In-Reply-To: <3C15A79A.98EC0ADB@zip.com.au>
In-Reply-To: <20011210191630.A13679@furble>, <1008035512.4287.1.camel@phantasy> <20011210191630.A13679@furble> <1008050718.4287.11.camel@phantasy> <3C15A79A.98EC0ADB@zip.com.au>
OK, I talked to Andrew off-list and we agree his fix is more correct.
It should be applied. I tested it (I have a consistent method of
reproducing the race under preempt-kernel) and it works.
I rediffed it against pre8 because I had trouble applying his, oddly.
Ignore previous patch. Marcelo, please apply. Seriously, this time.
Robert Love
--- linux-2.4.17-pre8/drivers/char/console.c Mon Dec 10 20:48:50 2001
+++ linux/drivers/char/console.c Tue Dec 11 02:52:44 2001
@@ -100,6 +100,7 @@
#include <linux/tqueue.h>
#include <linux/bootmem.h>
#include <linux/pm.h>
+#include <linux/smp_lock.h>
#include <asm/io.h>
#include <asm/system.h>
@@ -2348,17 +2349,25 @@
set_leds();
}
+/*
+ * we can race here against con_close, so we grab the bkl
+ * and check the pointer before calling set_cursor
+ */
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);
+ lock_kernel();
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();
+ unlock_kernel();
}
/*
prev parent reply other threads:[~2001-12-11 9:06 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-12-11 1:51 [PATCH] console close race fix resend Robert Love
2001-12-11 3:16 ` Gordon Oliver
2001-12-11 6:05 ` Robert Love
2001-12-11 6:28 ` Andrew Morton
2001-12-11 8:54 ` Gordon Oliver
2001-12-11 9:05 ` Robert Love [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1008061551.815.1.camel@phantasy \
--to=rml@tech9.net \
--cc=akpm@zip.com.au \
--cc=gordo@pincoya.com \
--cc=linux-kernel@vger.kernel.org \
--cc=marcelo@conectiva.com.br \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).