From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 0B43A1474B8; Thu, 13 Jun 2024 12:00:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718280057; cv=none; b=A9XNNyj4TF2ujE9Vm97t9SklNKkyGOgNO9RdsPHcY6eThNVff3uaj+ezdx0g1LkS4x2q6cpuQWu+yXZCQ5ZlMLcIw8+Ur40t1Uf78rLLO22zk/9XI92HI6MLYp6PkxDWbLEeakj/CtvZsXRIB6Zu+daRedxxWiuuytNQfYBZ4SA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718280057; c=relaxed/simple; bh=JTZ9cUSjDtFBhPDLJpTgRxAhXFuBEdQ9fbhogA9oLEI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=fuK8+ItktsuH52ZViFJQrUYFAPD5KnB/jJS1RB8jevqN+Wf7788g0f0M75JiBTvQNoa+Qm2aVsBhh7mdIdTUNupN0YJewMR8k2KwTWL+xtHXHl2zQiDlpZ5+5swNJetwzzgEv2a1sCzTAHZSaYBW0K2YHeHtnHxVobPlW1jK7nM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=LpvNkeWT; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="LpvNkeWT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3F6BAC2BBFC; Thu, 13 Jun 2024 12:00:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1718280056; bh=JTZ9cUSjDtFBhPDLJpTgRxAhXFuBEdQ9fbhogA9oLEI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LpvNkeWTi7iqc0BJuJN09WTBjjxs3lxheAZ26NIpYoHF7hUKGuZh0/1ndVk/mza48 o9wn9fIa48pjhF9DdJiorczDlqVvoyGnmPDTtAxHa/lXM9369dNL6OQ1P1ZEcCt1Jw XOK6teEXp4odIgjQRs9yynaPu9qNNhr+3s335HzY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Roberto Sassu , Johannes Berg , Richard Weinberger , Sasha Levin Subject: [PATCH 5.4 128/202] um: Add winch to winch_handlers before registering winch IRQ Date: Thu, 13 Jun 2024 13:33:46 +0200 Message-ID: <20240613113232.702137212@linuxfoundation.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240613113227.759341286@linuxfoundation.org> References: <20240613113227.759341286@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Roberto Sassu [ Upstream commit a0fbbd36c156b9f7b2276871d499c9943dfe5101 ] Registering a winch IRQ is racy, an interrupt may occur before the winch is added to the winch_handlers list. If that happens, register_winch_irq() adds to that list a winch that is scheduled to be (or has already been) freed, causing a panic later in winch_cleanup(). Avoid the race by adding the winch to the winch_handlers list before registering the IRQ, and rolling back if um_request_irq() fails. Fixes: 42a359e31a0e ("uml: SIGIO support cleanup") Signed-off-by: Roberto Sassu Reviewed-by: Johannes Berg Signed-off-by: Richard Weinberger Signed-off-by: Sasha Levin --- arch/um/drivers/line.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/arch/um/drivers/line.c b/arch/um/drivers/line.c index 4f2a4ac8a82bb..d6a78c3548a55 100644 --- a/arch/um/drivers/line.c +++ b/arch/um/drivers/line.c @@ -673,24 +673,26 @@ void register_winch_irq(int fd, int tty_fd, int pid, struct tty_port *port, goto cleanup; } - *winch = ((struct winch) { .list = LIST_HEAD_INIT(winch->list), - .fd = fd, + *winch = ((struct winch) { .fd = fd, .tty_fd = tty_fd, .pid = pid, .port = port, .stack = stack }); + spin_lock(&winch_handler_lock); + list_add(&winch->list, &winch_handlers); + spin_unlock(&winch_handler_lock); + if (um_request_irq(WINCH_IRQ, fd, IRQ_READ, winch_interrupt, IRQF_SHARED, "winch", winch) < 0) { printk(KERN_ERR "register_winch_irq - failed to register " "IRQ\n"); + spin_lock(&winch_handler_lock); + list_del(&winch->list); + spin_unlock(&winch_handler_lock); goto out_free; } - spin_lock(&winch_handler_lock); - list_add(&winch->list, &winch_handlers); - spin_unlock(&winch_handler_lock); - return; out_free: -- 2.43.0