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 1847A358378 for ; Mon, 5 Oct 2026 22:46:28 +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=1791240390; cv=none; b=oIjRcmudWwDGbQ48QwVVzq8rtZTeMW9LVppWN4EbG9+s4BduMLHWg2Fo5Y3/7l9RlIag53Q15D8VBAYmLtxcL3A91qhFh2vI1th7fHPAuAz9W8xeZVh89IzaD9KYvlMlTuafEGFFJK4/3DnwdWMmwmMkTWtjIvvJ5UALb1ozJCo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791240390; c=relaxed/simple; bh=OW/cqAmDcdxPcQpsJbGWxbSsjmsLeWOTHN9GKOPlneA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=tvNfQ2Ybq8zmlzLznx5qoh7YN5S8ADG40xR7cbNpyxHjcKC2BteH/VPs7BUmNcNnw+s9Zg9ZRZq5lBcqeWTOK7OQ+H2g+TNXGcpLwEA6gKd0xZwl3lL5V1p262bUKOD0rR9DKHRTOVkvcN93xkKHIZpfrFNdP1FoJ9jVUXYuXtM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=KWytlX28; 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="KWytlX28" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D01C31F000FF; Mon, 5 Oct 2026 22:46:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791240388; bh=x58iR7Vx3A0GWzdMHYqVSHeloQaKUFaadBmBoJ3hB+k=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=KWytlX28pSF5/Tax75KHr5BiPJ33cnnr2mKrOvAbwsXvOK6TT5HEeeez1RiygJ+fv wHo7/g5n7KROz/qAEk3GvmtP1vNWcWj+7kfkVGbuF0NP3QkLYfgsZCj3ZLzC6TTvtr TvD9U4t272pFsdU6WHP2/vt/eHQaaeHum44DrWX949RmfFbJBmXNMglnyCPSzeymBt VELnJNGjsTzwj3T3yWCL8rU1HD8BjVvkv6cpv3gNtbx3FVO6n0lehPd4/os7pM5qQm Fji/KDC5DHG1GPEAa8RnT6kCgs20x/3NhiW52rm8aH6Ux0e41be5BeSejLz7JDyQhz zCgyXnRloVSKQ== 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 6.1.y] serial: fix TIOCMIWAIT race Date: Mon, 5 Oct 2026 18:46:24 -0400 Message-ID: <20261005224600.3467867-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026100502-jab-vividly-0ef4@gregkh> References: <2026100502-jab-vividly-0ef4@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 spinlock calls instead of 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 2704eb8af5880..dafbd24b91484 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -1222,12 +1222,12 @@ 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