From nobody Fri Dec 19 12:49:39 2025 Received: from mail.hugovil.com (mail.hugovil.com [162.243.120.170]) (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 150FB37142; Tue, 19 Dec 2023 17:19:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=hugovil.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=hugovil.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=hugovil.com header.i=@hugovil.com header.b="ANj4Jjg4" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=hugovil.com ; s=x; h=Subject:Content-Transfer-Encoding:MIME-Version:Message-Id:Date:Cc:To :From:subject:date:message-id:reply-to; bh=rcIhJ0kSFRXFUqlpgMlBLBoMnyaUvKyVyUcSYmShbS8=; b=ANj4Jjg44+HlSkwnUCOx+b+JKG F8EE2tsJBGCsaIQTuYxz54VRJD7ZRrf+RyiXgaA0pPhuZBBXMbPXmpg7EjvwrhQ6A/A3Mj9l78gVz P6Os8z9R8BmkvQ9zH3AoZgXb2sO9Jcc6KHF2kNGVQlMa8YX050iB9355q6dFMGsm6cVY=; Received: from modemcable168.174-80-70.mc.videotron.ca ([70.80.174.168]:40128 helo=pettiford.lan) by mail.hugovil.com with esmtpa (Exim 4.92) (envelope-from ) id 1rFdkK-0007Ao-Bn; Tue, 19 Dec 2023 12:19:08 -0500 From: Hugo Villeneuve To: gregkh@linuxfoundation.org, jirislaby@kernel.org, jringle@gridpoint.com, kubakici@wp.pl, phil@raspberrypi.org, bo.svangard@embeddedart.se Cc: linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, hugo@hugovil.com, Hugo Villeneuve , stable@vger.kernel.org, Yury Norov Date: Tue, 19 Dec 2023 12:18:46 -0500 Message-Id: <20231219171903.3530985-3-hugo@hugovil.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20231219171903.3530985-1-hugo@hugovil.com> References: <20231219171903.3530985-1-hugo@hugovil.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-SA-Exim-Connect-IP: 70.80.174.168 X-SA-Exim-Mail-From: hugo@hugovil.com X-Spam-Level: X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * -0.0 T_SCC_BODY_TEXT_LINE No description available. Subject: [PATCH 02/18] serial: sc16is7xx: fix invalid sc16is7xx_lines bitfield in case of probe error X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on mail.hugovil.com) Content-Type: text/plain; charset="utf-8" From: Hugo Villeneuve If an error occurs during probing, the sc16is7xx_lines bitfield may be left in a state that doesn't represent the correct state of lines allocation. For example, in a system with two SC16 devices, if an error occurs only during probing of channel (port) B of the second device, sc16is7xx_lines final state will be 00001011b instead of the expected 00000011b. This is caused in part because of the "i--" in the for/loop located in the out_ports: error path. Fix this by checking the return value of uart_add_one_port() and set line allocation bit only if this was successful. This allows the refactor of the obfuscated for(i--...) loop in the error path, and properly call uart_remove_one_port() only when needed, and properly unset line allocation bits. Also use same mechanism in remove() when calling uart_remove_one_port(). Fixes: c64349722d14 ("sc16is7xx: support multiple devices") Cc: stable@vger.kernel.org Cc: Yury Norov Signed-off-by: Hugo Villeneuve --- There is already a patch by Yury Norov to simplify sc16is7xx_alloc_line(): https://lore.kernel.org/all/20231212022749.625238-30-yury.norov@gmail.com/ Since my patch gets rid of sc16is7xx_alloc_line() entirely, it would make Yury's patch unnecessary. --- drivers/tty/serial/sc16is7xx.c | 44 ++++++++++++++-------------------- 1 file changed, 18 insertions(+), 26 deletions(-) diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c index b585663c1e6e..b92fd01cfeec 100644 --- a/drivers/tty/serial/sc16is7xx.c +++ b/drivers/tty/serial/sc16is7xx.c @@ -407,19 +407,6 @@ static void sc16is7xx_port_update(struct uart_port *po= rt, u8 reg, regmap_update_bits(one->regmap, reg, mask, val); } =20 -static int sc16is7xx_alloc_line(void) -{ - int i; - - BUILD_BUG_ON(SC16IS7XX_MAX_DEVS > BITS_PER_LONG); - - for (i =3D 0; i < SC16IS7XX_MAX_DEVS; i++) - if (!test_and_set_bit(i, &sc16is7xx_lines)) - break; - - return i; -} - static void sc16is7xx_power(struct uart_port *port, int on) { sc16is7xx_port_update(port, SC16IS7XX_IER_REG, @@ -1550,6 +1537,13 @@ static int sc16is7xx_probe(struct device *dev, SC16IS7XX_IOCONTROL_SRESET_BIT); =20 for (i =3D 0; i < devtype->nr_uart; ++i) { + s->p[i].port.line =3D find_first_zero_bit(&sc16is7xx_lines, + SC16IS7XX_MAX_DEVS); + if (s->p[i].port.line >=3D SC16IS7XX_MAX_DEVS) { + ret =3D -ERANGE; + goto out_ports; + } + /* Initialize port data */ s->p[i].port.dev =3D dev; s->p[i].port.irq =3D irq; @@ -1569,14 +1563,8 @@ static int sc16is7xx_probe(struct device *dev, s->p[i].port.rs485_supported =3D sc16is7xx_rs485_supported; s->p[i].port.ops =3D &sc16is7xx_ops; s->p[i].old_mctrl =3D 0; - s->p[i].port.line =3D sc16is7xx_alloc_line(); s->p[i].regmap =3D regmaps[i]; =20 - if (s->p[i].port.line >=3D SC16IS7XX_MAX_DEVS) { - ret =3D -ENOMEM; - goto out_ports; - } - mutex_init(&s->p[i].efr_lock); =20 ret =3D uart_get_rs485_mode(&s->p[i].port); @@ -1594,8 +1582,13 @@ static int sc16is7xx_probe(struct device *dev, kthread_init_work(&s->p[i].tx_work, sc16is7xx_tx_proc); kthread_init_work(&s->p[i].reg_work, sc16is7xx_reg_proc); kthread_init_delayed_work(&s->p[i].ms_work, sc16is7xx_ms_proc); + /* Register port */ - uart_add_one_port(&sc16is7xx_uart, &s->p[i].port); + ret =3D uart_add_one_port(&sc16is7xx_uart, &s->p[i].port); + if (ret) + goto out_ports; + + set_bit(s->p[i].port.line, &sc16is7xx_lines); =20 /* Enable EFR */ sc16is7xx_port_write(&s->p[i].port, SC16IS7XX_LCR_REG, @@ -1653,10 +1646,9 @@ static int sc16is7xx_probe(struct device *dev, #endif =20 out_ports: - for (i--; i >=3D 0; i--) { - uart_remove_one_port(&sc16is7xx_uart, &s->p[i].port); - clear_bit(s->p[i].port.line, &sc16is7xx_lines); - } + for (i =3D 0; i < devtype->nr_uart; i++) + if (test_and_clear_bit(s->p[i].port.line, &sc16is7xx_lines)) + uart_remove_one_port(&sc16is7xx_uart, &s->p[i].port); =20 kthread_stop(s->kworker_task); =20 @@ -1683,8 +1675,8 @@ static void sc16is7xx_remove(struct device *dev) =20 for (i =3D 0; i < s->devtype->nr_uart; i++) { kthread_cancel_delayed_work_sync(&s->p[i].ms_work); - uart_remove_one_port(&sc16is7xx_uart, &s->p[i].port); - clear_bit(s->p[i].port.line, &sc16is7xx_lines); + if (test_and_clear_bit(s->p[i].port.line, &sc16is7xx_lines)) + uart_remove_one_port(&sc16is7xx_uart, &s->p[i].port); sc16is7xx_power(&s->p[i].port, 0); } =20 --=20 2.39.2