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[34.82.187.25]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-88725881fa6sm376732b3a.27.2026.09.30.00.48.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 30 Sep 2026 00:48:53 -0700 (PDT) From: Hui Peng To: Greg Kroah-Hartman , Jiri Slaby , John Ogness , =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= Cc: Andy Shevchenko , linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Hui Peng Subject: [PATCH v6 1/3] serial: 8250: fix deadlock in serial8250_register_ports() Date: Wed, 30 Sep 2026 07:48:48 +0000 Message-ID: <20260930074850.465003-2-benquike@gmail.com> X-Mailer: git-send-email 2.56.0.rc1.315.gc6ed9934b7-goog In-Reply-To: <20260930074850.465003-1-benquike@gmail.com> References: <20260930074850.465003-1-benquike@gmail.com> Precedence: bulk X-Mailing-List: linux-serial@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit In serial8250_register_ports(), mutex_lock(&hash_mutex) is acquired while holding spinlock_t serial_port_lock during IRQ chain registration: spin_lock_irqsave(&serial_port_lock, flags); mutex_lock(&hash_mutex); Acquiring a sleeping mutex while holding a spinlock causes a sleeping-while-atomic bug and potential deadlock. Replace mutex_lock(&hash_mutex) with spin_lock_irqsave() in serial8250_register_ports(). Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Reviewed-by: Ilpo Järvinen Assisted-by: LLM Signed-off-by: Hui Peng --- drivers/tty/serial/8250/8250_core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c index 9e4f5a2a2eaa..f64a1b0a2eaa 100644 --- a/drivers/tty/serial/8250/8250_core.c +++ b/drivers/tty/serial/8250/8250_core.c @@ -102,9 +102,9 @@ static void serial8250_register_ports(struct uart_driver *drv, struct uart_8250_port *up; for (i = 0; i < nr; i++) { - up = &serial8250_ports[i]; + up = &serial8250_ports[i]; up->port.dev = dev; } }