From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B61E6A95E for ; Tue, 6 Oct 2026 00:10:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791245402; cv=none; b=FRACr0vlpbVibgzYganoXnrYMJmIwWDtvzbVc4btfxrDRxXOeUhUrpLraQrnh4GZsVAzfNqCEZ6UT7tLmdbVaEnM4mFUGNYsBJSoqckXdySI1udfQ2w+cCb7P4ymStMF+YIUs155QhoLp17ENOkaB+fqjgV11GphzGu+/O+pGeM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791245402; c=relaxed/simple; bh=FiAYnZG2TOLx25jsLOLBbbCPLuDoH948pSpJsA6ECKA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=erAW7ViU9zpPq9AC4oKe/i+SfnUjxoMOir5nWhznnnw8Vc0SP6gpyDcfor7tI9fH+E2AKRjueBVUdHCPiPJaYHA8clqHoJgjPBQuYq3M1abad1jOG1g8SfgAWil7v1kGFdLjwsB/6L+XJlG0jFrNddsSprY3Bqi116wupl0DOJ8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=CvBwuzbv; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="CvBwuzbv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A74D81F000FF; Tue, 6 Oct 2026 00:09:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791245401; bh=BgkRiRRoU+qW2Cm7G2n3lXSJB53JwHWg1usaePKXlSU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=CvBwuzbv2apIxGSol96vURK/Ym1covpUsi2nRyO/54SIBOWNhJNGUSjn+N72nkZxL blIYI4MYdRnanj2JqMacS7/ZRhW4P1ICoiWykz5QXiBoRUc5hnEbR8NugPmq9utrfw cpb2utgA12GEz2fD2sdv+obA761n5NQhrt0etLDUimfP5jvbi+DNCQieKhp0WCUO0+ rasb6xCwNx+uvLN4wbmP//xduVxkvYpZcuKylajWw6Js6RTE8aIkyMHRHo1Ld+Dvgv mauSmveQhGFC8Zh3VGfxrtY7mRv9hRNtADWSUKsObzuOOzwDPeEVw9BcVw9LrMNOVd 7ZC/2EYsdbzJg== From: Sasha Levin To: stable@vger.kernel.org Cc: Johan Hovold , sashiko-bot@kernel.org, stable@kernel.org, Greg Kroah-Hartman , Sasha Levin Subject: [PATCH 5.15.y] serial: fix TIOCMIWAIT race Date: Mon, 5 Oct 2026 20:09:57 -0400 Message-ID: <20261006000903.3542569-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026100502-seducing-scabbed-7835@gregkh> References: <2026100502-seducing-scabbed-7835@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Johan Hovold [ Upstream commit 40adffec8c0090533dfaa863ced7901b60bbf1dc ] The task state must be updated before checking the wakeup condition to avoid missing a racing modem status update. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: sashiko-bot@kernel.org Link: https://lore.kernel.org/r/20260904115542.E20D11F00A3D@smtp.kernel.org Cc: stable@kernel.org Signed-off-by: Johan Hovold Link: https://patch.msgid.link/20260910130816.642699-4-johan@kernel.org Signed-off-by: Greg Kroah-Hartman [ sashal: Adjusted context for direct spin_lock_irq() and spin_unlock_irq() calls. ] Signed-off-by: Sasha Levin --- drivers/tty/serial/serial_core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 404354727d194..1cba822e068e9 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -1213,12 +1213,12 @@ static int uart_wait_modem_status(struct uart_state *state, unsigned long arg) add_wait_queue(&port->delta_msr_wait, &wait); for (;;) { + set_current_state(TASK_INTERRUPTIBLE); + spin_lock_irq(&uport->lock); memcpy(&cnow, &uport->icount, sizeof(struct uart_icount)); spin_unlock_irq(&uport->lock); - set_current_state(TASK_INTERRUPTIBLE); - if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) || ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) || ((arg & TIOCM_CD) && (cnow.dcd != cprev.dcd)) || -- 2.53.0