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 26DD737F735 for ; Mon, 5 Oct 2026 22:12:49 +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=1791238371; cv=none; b=crU4VGNvoL8uyYLtrtIO7UTk4mO1LdkxAHLTJ3D7NiGF3c/sO/q/PADxkJCzSnmhpcSBN5y3aHQoK1IGlQY6RaR4A+k0qkvO/MgDDbNfEzO5lzkzafZsjaCg4RqV7pZ+ZabWSZU9o4rLtMVrnMLZqkrkptGZpuidpyjqfLRqsfs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791238371; c=relaxed/simple; bh=51r7Qn1EdOh4+IU4xRj67TOm56yzhQpLTGe5BxNhkBE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=TBEWTcEFdH1BtTM9Ryut04iJiTVHN5Q0q/OyFpQ8ajNWOjRpQLN83bjabXTLiYOFspgQaL7eXbWPFcgDKNWivQ2YYFoH6vAjaU+pEnOwdKbd/ar2SAWCDIDwwQ+6l8Ps+d816Duw2axeeyW2tQD69nbo4d7+4n5SrVjcNo4VCzQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=e3BnIJCX; 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="e3BnIJCX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4F8AA1F000FF; Mon, 5 Oct 2026 22:12:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791238369; bh=MULkRSjL5V/Ei6Ziy/VHbivuXzk0TiwsZl/8cle5vNc=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=e3BnIJCX4Tx9zxSLVKxYiHRB7R/I/w5ZxU4RiVE/J1ltyMFHVyDBZB7GiRyt0RMMB MYXU2vGeQEaEc2Guyus7D+qjrVwZpm1DJO6QMmQAMg2PEYdd+ukplA6xD7C7GOUYUA 7fIT5rTTpNV9O5RT3sW0iKnAetOR1RaCNBNwYZC+8wYnaNJsPbEya0mrumE6neB4xk pctHeRz0iJ58LIgJgAyg0rbDqvAg3u6y4xMOkTTIAPFLSicep8iR810+23CHvbieIe ABez/nVC2ZqdxhGQNih50P/Km9gPj14d8qI/UnnLs6GyKFwfn2Sa6CNqZWyFb9H2hZ IWnlsFkef/Y7g== 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 6.6.y] serial: fix TIOCMIWAIT race Date: Mon, 5 Oct 2026 18:12:45 -0400 Message-ID: <20261005221224.3435172-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026100501-rubber-equipment-9072@gregkh> References: <2026100501-rubber-equipment-9072@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: Retained direct spinlock calls instead of the upstream UART port locking helpers. ] 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 c3a51bd59ff74..87bd1be81f77c 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -1253,12 +1253,12 @@ 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