Messages in this thread Patch in this message | | | From | Earl Chew <> | Subject | [PATCH 1/3] tty: Fix __tty_check_change() and tiocspgrp() race | Date | Thu, 31 Aug 2023 18:50:29 -0700 |
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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
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