From ed2761958ad77e54791802b07095786150eab844 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= Date: Tue, 10 Dec 2024 19:01:20 +0200 Subject: [PATCH 1/3] tty: serial: 8250: Fix another runtime PM usage counter underflow MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The commit f9b11229b79c ("serial: 8250: Fix PM usage_count for console handover") fixed one runtime PM usage counter balance problem that occurs because .dev is not set during univ8250 setup preventing call to pm_runtime_get_sync(). Later, univ8250_console_exit() will trigger the runtime PM usage counter underflow as .dev is already set at that time. Call pm_runtime_get_sync() to balance the RPM usage counter also in serial8250_register_8250_port() before trying to add the port. Reported-by: Borislav Petkov (AMD) Fixes: bedb404e91bb ("serial: 8250_port: Don't use power management for kernel console") Cc: stable Tested-by: Borislav Petkov (AMD) Signed-off-by: Ilpo Järvinen Link: https://lore.kernel.org/r/20241210170120.2231-1-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_core.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c index 5f9f06911795c..68baf75bdadc4 100644 --- a/drivers/tty/serial/8250/8250_core.c +++ b/drivers/tty/serial/8250/8250_core.c @@ -812,6 +812,9 @@ int serial8250_register_8250_port(const struct uart_8250_port *up) uart->dl_write = up->dl_write; if (uart->port.type != PORT_8250_CIR) { + if (uart_console_registered(&uart->port)) + pm_runtime_get_sync(uart->port.dev); + if (serial8250_isa_config != NULL) serial8250_isa_config(0, &uart->port, &uart->capabilities); From fbd22c4fa737f9559be8b87a73bb1cdfcd39fd11 Mon Sep 17 00:00:00 2001 From: Xiaolei Wang Date: Wed, 11 Dec 2024 07:36:13 +0800 Subject: [PATCH 2/3] serial: imx: Use uart_port_lock_irq() instead of uart_port_lock() When executing 'echo mem > /sys/power/state', the following deadlock occurs. Since there is output during the serial port entering the suspend process, the suspend will be interrupted, resulting in the nesting of locks. Therefore, use uart_port_lock_irq() instead of uart_port_unlock(). WARNING: inconsistent lock state 6.12.0-rc2-00002-g3c199ed5bd64-dirty #23 Not tainted -------------------------------- inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage. sh/494 [HC0[0]:SC0[0]:HE1:SE1] takes: c4db5850 (&port_lock_key){?.-.}-{3:3}, at: imx_uart_enable_wakeup+0x14/0x254 {IN-HARDIRQ-W} state was registered at: lock_acquire+0x104/0x348 _raw_spin_lock+0x48/0x84 imx_uart_int+0x14/0x4dc __handle_irq_event_percpu+0xac/0x2fc handle_irq_event_percpu+0xc/0x40 handle_irq_event+0x38/0x8c handle_fasteoi_irq+0xb4/0x1b8 handle_irq_desc+0x1c/0x2c gic_handle_irq+0x6c/0xa0 generic_handle_arch_irq+0x2c/0x64 call_with_stack+0x18/0x20 __irq_svc+0x9c/0xbc _raw_spin_unlock_irqrestore+0x2c/0x48 uart_write+0xd8/0x3a0 do_output_char+0x1a8/0x1e4 n_tty_write+0x224/0x440 file_tty_write.constprop.0+0x124/0x250 do_iter_readv_writev+0x100/0x1e0 vfs_writev+0xc4/0x448 do_writev+0x68/0xf8 ret_fast_syscall+0x0/0x1c irq event stamp: 31593 hardirqs last enabled at (31593): [] _raw_spin_unlock_irqrestore+0x44/0x48 hardirqs last disabled at (31592): [] clk_enable_lock+0x60/0x120 softirqs last enabled at (30334): [] handle_softirqs+0x2cc/0x478 softirqs last disabled at (30325): [] __irq_exit_rcu+0x120/0x15c other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&port_lock_key); lock(&port_lock_key); Fixes: 3c199ed5bd64 ("serial: imx: Grab port lock in imx_uart_enable_wakeup()") Signed-off-by: Xiaolei Wang Reviewed-by: Lucas Stach Reviewed-by: Fabio Estevam Link: https://lore.kernel.org/r/20241210233613.2881264-1-xiaolei.wang@windriver.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/imx.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index 17f70e4bee435..9c59ec128bb4f 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -2692,7 +2692,7 @@ static void imx_uart_enable_wakeup(struct imx_port *sport, bool on) { u32 ucr3; - uart_port_lock(&sport->port); + uart_port_lock_irq(&sport->port); ucr3 = imx_uart_readl(sport, UCR3); if (on) { @@ -2714,7 +2714,7 @@ static void imx_uart_enable_wakeup(struct imx_port *sport, bool on) imx_uart_writel(sport, ucr1, UCR1); } - uart_port_unlock(&sport->port); + uart_port_unlock_irq(&sport->port); } static int imx_uart_suspend_noirq(struct device *dev) From 0cfc36ea51684b5932cd3951ded523777d807af2 Mon Sep 17 00:00:00 2001 From: Ben Wolsieffer Date: Mon, 16 Dec 2024 09:53:23 -0500 Subject: [PATCH 3/3] serial: stm32: use port lock wrappers for break control Commit 30e945861f3b ("serial: stm32: add support for break control") added another usage of the port lock, but was merged on the same day as c5d06662551c ("serial: stm32: Use port lock wrappers"), therefore the latter did not update this usage to use the port lock wrappers. Fixes: c5d06662551c ("serial: stm32: Use port lock wrappers") Cc: stable Signed-off-by: Ben Wolsieffer Reviewed-by: John Ogness Link: https://lore.kernel.org/r/20241216145323.111612-1-ben.wolsieffer@hefring.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/stm32-usart.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index 7dc2545460751..1ec5d8c3aef8d 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -1051,14 +1051,14 @@ static void stm32_usart_break_ctl(struct uart_port *port, int break_state) const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; unsigned long flags; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); if (break_state) stm32_usart_set_bits(port, ofs->rqr, USART_RQR_SBKRQ); else stm32_usart_clr_bits(port, ofs->rqr, USART_RQR_SBKRQ); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } static int stm32_usart_startup(struct uart_port *port)