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 BEB471F937; Thu, 13 Jun 2024 12:37:44 +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=1718282264; cv=none; b=BmjIhNsPG0vnnZxGq9z6Ny2S+mhkWKv8CB6H/DlIi6B01z4Qk9K9EjXRdLRhKwxJihvxkQdkjHy8+wQcHhrq5Jgd1eXyrKV8n9Ai1eU4kgzlU1bBC+TYvImt/TJewdajoJzz7QW8eohwPzNbxaJZ4jEXNYnC59k+PilXfdOfbr4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718282264; c=relaxed/simple; bh=IfGS+bg81Gb5IIY9ghi7bpWxei0kR5phRIxNQFn/yYg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=AR9KDEkZgsUz0+owuhqDMYGl/BpmX9DWvFWaEuw9nveuNUeXFu+wPyMdLgQPtrWtu12Zq0lVcP4e9Tl947In+t/9OA9nRHOw3Z4IpuehDMgGq0I9e8ggq2NVCBcf5UnazDNISyjZ6Krh2oRRGxFKXhtvvufdtdAYDgtVcR41UHk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=g/mlLVzU; 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="g/mlLVzU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 46538C2BBFC; Thu, 13 Jun 2024 12:37:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1718282264; bh=IfGS+bg81Gb5IIY9ghi7bpWxei0kR5phRIxNQFn/yYg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=g/mlLVzUZj9LywqZrsa8D49VnSOp6wQD1Zrg7Vo8sXgLyLq7ZqwrBNs8CMnry+BWu cJ1dw0AVhm+6cXNcPqlRuIXO0a0R2uNrsP1y9m7naknMDGrpUyAA8gdGyaJAKf8qCg u3WzaGgOyyMnH941xGGG7OA5+bOTq6Qxp77NyH2s= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Andy Shevchenko , Hugo Villeneuve , Sasha Levin Subject: [PATCH 5.15 187/402] serial: max3100: Update uart_driver_registered on driver removal Date: Thu, 13 Jun 2024 13:32:24 +0200 Message-ID: <20240613113309.441518536@linuxfoundation.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240613113302.116811394@linuxfoundation.org> References: <20240613113302.116811394@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-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Andy Shevchenko [ Upstream commit 712a1fcb38dc7cac6da63ee79a88708fbf9c45ec ] The removal of the last MAX3100 device triggers the removal of the driver. However, code doesn't update the respective global variable and after insmod — rmmod — insmod cycle the kernel oopses: max3100 spi-PRP0001:01: max3100_probe: adding port 0 BUG: kernel NULL pointer dereference, address: 0000000000000408 ... RIP: 0010:serial_core_register_port+0xa0/0x840 ... max3100_probe+0x1b6/0x280 [max3100] spi_probe+0x8d/0xb0 Update the actual state so next time UART driver will be registered again. Hugo also noticed, that the error path in the probe also affected by having the variable set, and not cleared. Instead of clearing it move the assignment after the successfull uart_register_driver() call. Fixes: 7831d56b0a35 ("tty: MAX3100") Signed-off-by: Andy Shevchenko Reviewed-by: Hugo Villeneuve Link: https://lore.kernel.org/r/20240402195306.269276-3-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/tty/serial/max3100.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/tty/serial/max3100.c b/drivers/tty/serial/max3100.c index b3b77ffd5b423..24cd345ea6e3d 100644 --- a/drivers/tty/serial/max3100.c +++ b/drivers/tty/serial/max3100.c @@ -751,13 +751,14 @@ static int max3100_probe(struct spi_device *spi) mutex_lock(&max3100s_lock); if (!uart_driver_registered) { - uart_driver_registered = 1; retval = uart_register_driver(&max3100_uart_driver); if (retval) { printk(KERN_ERR "Couldn't register max3100 uart driver\n"); mutex_unlock(&max3100s_lock); return retval; } + + uart_driver_registered = 1; } for (i = 0; i < MAX_MAX3100; i++) @@ -843,6 +844,7 @@ static int max3100_remove(struct spi_device *spi) } pr_debug("removing max3100 driver\n"); uart_unregister_driver(&max3100_uart_driver); + uart_driver_registered = 0; mutex_unlock(&max3100s_lock); return 0; -- 2.43.0