From: Earl Chew <earl.chew@yahoo.ca>
To: linux-kernel@vger.kernel.org, gregkh@linuxfoundation.org,
jirislaby@kernel.org
Cc: peter@hurleysoftware.com, earl.chew@yahoo.ca
Subject: [PATCH 1/3] tty: Fix __tty_check_change() and tiocspgrp() race
Date: Thu, 31 Aug 2023 18:50:29 -0700 [thread overview]
Message-ID: <20230901015030.2469062-2-earl.chew@yahoo.ca> (raw)
In-Reply-To: <20230831143645.2298799-1-earl_chew@yahoo.com>
Restore the use of tty->ctrl.lock to cover both checking
current->task_pgrp() and sending kill_pgrp(). This coverage
was lost for SIGTTIN as part of commit 2812d9e9fd94
(tty: Combine SIGTTOU/SIGTTIN handling). In rare cases,
job control shells using tcsetpgrp() and SIGCONT to move
a background job to the foreground could find the new
foreground job stopping almost immediately due to SIGTTIN
or SIGTTOU.
Signed-off-by: Earl Chew <earl.chew@yahoo.ca>
---
drivers/tty/tty_jobctrl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/tty/tty_jobctrl.c b/drivers/tty/tty_jobctrl.c
index 0d04287da..aba721a3c 100644
--- a/drivers/tty/tty_jobctrl.c
+++ b/drivers/tty/tty_jobctrl.c
@@ -44,7 +44,6 @@ int __tty_check_change(struct tty_struct *tty, int sig)
spin_lock_irqsave(&tty->ctrl.lock, flags);
tty_pgrp = tty->ctrl.pgrp;
- spin_unlock_irqrestore(&tty->ctrl.lock, flags);
if (tty_pgrp && pgrp != tty_pgrp) {
if (is_ignored(sig)) {
@@ -58,6 +57,7 @@ int __tty_check_change(struct tty_struct *tty, int sig)
ret = -ERESTARTSYS;
}
}
+ spin_unlock_irqrestore(&tty->ctrl.lock, flags);
rcu_read_unlock();
if (!tty_pgrp)
--
2.39.1
next prev parent reply other threads:[~2023-09-01 1:51 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20230831143645.2298799-1-earl_chew@yahoo.com>
2023-09-01 1:50 ` [PATCH 0/3] tty: Fix tiocspgrp() related races Earl Chew
2023-09-28 13:06 ` [PATCH v2 " Earl Chew
2023-09-28 13:38 ` Greg KH
2023-09-28 13:06 ` [PATCH v2 1/3] tty: Fix __tty_check_change() and tiocspgrp() race Earl Chew
2023-09-28 13:06 ` [PATCH v2 2/3] tty: Serialise racing tiocspgrp() callers Earl Chew
2023-09-29 6:07 ` kernel test robot
2023-09-28 13:06 ` [PATCH v2 3/3] tty: Move task_pgrp() after tty->ctrl.lock for consistency Earl Chew
2023-09-01 1:50 ` Earl Chew [this message]
2023-09-01 1:50 ` [PATCH 2/3] tty: Serialise racing tiocspgrp() callers Earl Chew
2023-09-01 16:09 ` kernel test robot
2023-09-01 17:14 ` kernel test robot
2023-09-28 21:00 ` kernel test robot
2023-09-01 1:50 ` [PATCH 3/3] tty: Move task_pgrp() after tty->ctrl.lock for consistency Earl Chew
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