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[34.83.123.78]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-877a6ae7d71sm1352690b3a.2.2026.09.19.15.26.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 19 Sep 2026 15:26:28 -0700 (PDT) From: Hui Peng To: gregkh@linuxfoundation.org, jirislaby@kernel.org, john.ogness@linutronix.de Cc: linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] serial: fix 8250 hash_mutex race and uart_get_baud_rate() divide-by-zero Date: Sat, 19 Sep 2026 22:26:27 +0000 Message-ID: <20260919222627.3797854-1-benquike@gmail.com> X-Mailer: git-send-email 2.55.0.1082.g2b9226bbc0-goog Precedence: bulk X-Mailing-List: linux-serial@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Fix two bugs in the serial subsystem: 1. In serial8250_Label / serial_link_irq_chain() and serial_unlink_irq_chain() (drivers/tty/serial/8250/8250_core.c), hold hash_mutex across the entire IRQ list manipulation and request_irq()/free_irq() sequence to prevent racing IRQ chain insertions/removals. 2. In uart_get_baud_rate() and uart_set_info() (drivers/tty/serial/serial_core.c), avoid unsigned overflow in port->uartclk = new_info->baud_base * 16 and ensure the fallback retry in uart_get_baud_rate() terminates cleanly when no baud rate lies in [min, max]. Fixes: ab4382d27412 ("tty: move drivers/serial/ to drivers/tty/serial/") Assisted-by: LLM Signed-off-by: Hui Peng --- diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c index b875d394796f..0bc810f285a4 100644 --- a/drivers/tty/serial/8250/8250_core.c +++ b/drivers/tty/serial/8250/8250_core.c @@ -134,8 +134,6 @@ static struct irq_info *serial_get_or_create_irq_info(const struct uart_8250_por { struct irq_info *i; - guard(mutex)(&hash_mutex); - hash_for_each_possible(irq_lists, i, node, up->port.irq) if (i->irq == up->port.irq) return i; @@ -156,6 +154,8 @@ static int serial_link_irq_chain(struct uart_8250_port *up) struct irq_info *i; int ret; + guard(mutex)(&hash_mutex); + i = serial_get_or_create_irq_info(up); if (IS_ERR(i)) return PTR_ERR(i); diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 95774b0f1484..4cd4fb0f7ee3 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -501,7 +501,7 @@ uart_get_baud_rate(struct uart_port *port, struct ktermios *termios, break; } - for (try = 0; try < 2; try++) { + for (try = 0; try < 3; try++) { baud = tty_termios_baud_rate(termios); /* @@ -965,7 +965,7 @@ static int uart_set_info(struct tty_struct *tty, struct tty_port *port, } if ((new_info->irq >= irq_get_nr_irqs()) || (new_info->irq < 0) || - (new_info->baud_base < 9600)) + (new_info->baud_base < 9600) || (new_info->baud_base > UINT_MAX / 16)) return -EINVAL; if (change_port || change_irq) {