February 2023 - Linux-stable-mirror

FAILED: patch "[PATCH] serial: stm32: Merge hard IRQ and threaded IRQ handling into" failed to apply to 5.15-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. Possible dependencies: 3f6c02fa712b ("serial: stm32: Merge hard IRQ and threaded IRQ handling into single IRQ handler") 6333a4850621 ("serial: stm32: push DMA RX data before suspending") 6eeb348c8482 ("serial: stm32: terminate / restart DMA transfer at suspend / resume") e0abc903deea ("serial: stm32: rework RX dma initialization and release") d1ec8a2eabe9 ("serial: stm32: update throttle and unthrottle ops for dma mode") 33bb2f6ac308 ("serial: stm32: rework RX over DMA") cc58d0a3f0a4 ("serial: stm32: re-introduce an irq flag condition in usart_receive_chars") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 3f6c02fa712bd453871877fe1d1969625617471e Mon Sep 17 00:00:00 2001 From: Marek Vasut <marex(a)denx.de> Date: Fri, 20 Jan 2023 17:03:32 +0100 Subject: [PATCH] serial: stm32: Merge hard IRQ and threaded IRQ handling into single IRQ handler Requesting an interrupt with IRQF_ONESHOT will run the primary handler in the hard-IRQ context even in the force-threaded mode. The force-threaded mode is used by PREEMPT_RT in order to avoid acquiring sleeping locks (spinlock_t) in hard-IRQ context. This combination makes it impossible and leads to "sleeping while atomic" warnings. Use one interrupt handler for both handlers (primary and secondary) and drop the IRQF_ONESHOT flag which is not needed. Fixes: e359b4411c283 ("serial: stm32: fix threaded interrupt handling") Reviewed-by: Sebastian Andrzej Siewior <bigeasy(a)linutronix.de> Tested-by: Valentin Caron <valentin.caron(a)foss.st.com> # V3 Signed-off-by: Marek Vasut <marex(a)denx.de> Cc: stable(a)vger.kernel.org Link: https://lore.kernel.org/r/20230120160332.57930-1-marex@denx.de Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index a1490033aa16..409e91d6829a 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -797,25 +797,11 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr) spin_unlock(&port->lock); } - if (stm32_usart_rx_dma_enabled(port)) - return IRQ_WAKE_THREAD; - else - return IRQ_HANDLED; -} - -static irqreturn_t stm32_usart_threaded_interrupt(int irq, void *ptr) -{ - struct uart_port *port = ptr; - struct tty_port *tport = &port->state->port; - struct stm32_port *stm32_port = to_stm32_port(port); - unsigned int size; - unsigned long flags; - /* Receiver timeout irq for DMA RX */ - if (!stm32_port->throttled) { - spin_lock_irqsave(&port->lock, flags); + if (stm32_usart_rx_dma_enabled(port) && !stm32_port->throttled) { + spin_lock(&port->lock); size = stm32_usart_receive_chars(port, false); - uart_unlock_and_check_sysrq_irqrestore(port, flags); + uart_unlock_and_check_sysrq(port); if (size) tty_flip_buffer_push(tport); } @@ -1015,10 +1001,8 @@ static int stm32_usart_startup(struct uart_port *port) u32 val; int ret; - ret = request_threaded_irq(port->irq, stm32_usart_interrupt, - stm32_usart_threaded_interrupt, - IRQF_ONESHOT | IRQF_NO_SUSPEND, - name, port); + ret = request_irq(port->irq, stm32_usart_interrupt, + IRQF_NO_SUSPEND, name, port); if (ret) return ret; @@ -1601,13 +1585,6 @@ static int stm32_usart_of_dma_rx_probe(struct stm32_port *stm32port, struct dma_slave_config config; int ret; - /* - * Using DMA and threaded handler for the console could lead to - * deadlocks. - */ - if (uart_console(port)) - return -ENODEV; - stm32port->rx_buf = dma_alloc_coherent(dev, RX_BUF_L, &stm32port->rx_dma_buf, GFP_KERNEL);

2 years, 2 months

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FAILED: patch "[PATCH] serial: 8250_dma: Fix DMA Rx completion race" failed to apply to 4.14-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. Possible dependencies: 31352811e13d ("serial: 8250_dma: Fix DMA Rx completion race") 56dc5074cbec ("serial: 8250_dma: Rearm DMA Rx if more data is pending") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 31352811e13dc2313f101b890fd4b1ce760b5fe7 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen(a)linux.intel.com> Date: Mon, 30 Jan 2023 13:48:40 +0200 Subject: [PATCH] serial: 8250_dma: Fix DMA Rx completion race MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit __dma_rx_complete() is called from two places: - Through the DMA completion callback dma_rx_complete() - From serial8250_rx_dma_flush() after IIR_RLSI or IIR_RX_TIMEOUT The former does not hold port's lock during __dma_rx_complete() which allows these two to race and potentially insert the same data twice. Extend port's lock coverage in dma_rx_complete() to prevent the race and check if the DMA Rx is still pending completion before calling into __dma_rx_complete(). Reported-by: Gilles BULOZ <gilles.buloz(a)kontron.com> Tested-by: Gilles BULOZ <gilles.buloz(a)kontron.com> Fixes: 9ee4b83e51f7 ("serial: 8250: Add support for dmaengine") Cc: stable(a)vger.kernel.org Signed-off-by: Ilpo Järvinen <ilpo.jarvinen(a)linux.intel.com> Link: https://lore.kernel.org/r/20230130114841.25749-2-ilpo.jarvinen@linux.intel.… Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c index 37d6af2ec427..5594883a96f8 100644 --- a/drivers/tty/serial/8250/8250_dma.c +++ b/drivers/tty/serial/8250/8250_dma.c @@ -62,9 +62,14 @@ static void dma_rx_complete(void *param) struct uart_8250_dma *dma = p->dma; unsigned long flags; - __dma_rx_complete(p); - spin_lock_irqsave(&p->port.lock, flags); + if (dma->rx_running) + __dma_rx_complete(p); + + /* + * Cannot be combined with the previous check because __dma_rx_complete() + * changes dma->rx_running. + */ if (!dma->rx_running && (serial_lsr_in(p) & UART_LSR_DR)) p->dma->rx_dma(p); spin_unlock_irqrestore(&p->port.lock, flags);

2 years, 2 months

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FAILED: patch "[PATCH] serial: 8250_dma: Fix DMA Rx completion race" failed to apply to 4.19-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. Possible dependencies: 31352811e13d ("serial: 8250_dma: Fix DMA Rx completion race") 56dc5074cbec ("serial: 8250_dma: Rearm DMA Rx if more data is pending") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 31352811e13dc2313f101b890fd4b1ce760b5fe7 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen(a)linux.intel.com> Date: Mon, 30 Jan 2023 13:48:40 +0200 Subject: [PATCH] serial: 8250_dma: Fix DMA Rx completion race MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit __dma_rx_complete() is called from two places: - Through the DMA completion callback dma_rx_complete() - From serial8250_rx_dma_flush() after IIR_RLSI or IIR_RX_TIMEOUT The former does not hold port's lock during __dma_rx_complete() which allows these two to race and potentially insert the same data twice. Extend port's lock coverage in dma_rx_complete() to prevent the race and check if the DMA Rx is still pending completion before calling into __dma_rx_complete(). Reported-by: Gilles BULOZ <gilles.buloz(a)kontron.com> Tested-by: Gilles BULOZ <gilles.buloz(a)kontron.com> Fixes: 9ee4b83e51f7 ("serial: 8250: Add support for dmaengine") Cc: stable(a)vger.kernel.org Signed-off-by: Ilpo Järvinen <ilpo.jarvinen(a)linux.intel.com> Link: https://lore.kernel.org/r/20230130114841.25749-2-ilpo.jarvinen@linux.intel.… Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c index 37d6af2ec427..5594883a96f8 100644 --- a/drivers/tty/serial/8250/8250_dma.c +++ b/drivers/tty/serial/8250/8250_dma.c @@ -62,9 +62,14 @@ static void dma_rx_complete(void *param) struct uart_8250_dma *dma = p->dma; unsigned long flags; - __dma_rx_complete(p); - spin_lock_irqsave(&p->port.lock, flags); + if (dma->rx_running) + __dma_rx_complete(p); + + /* + * Cannot be combined with the previous check because __dma_rx_complete() + * changes dma->rx_running. + */ if (!dma->rx_running && (serial_lsr_in(p) & UART_LSR_DR)) p->dma->rx_dma(p); spin_unlock_irqrestore(&p->port.lock, flags);

2 years, 2 months

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FAILED: patch "[PATCH] serial: 8250_dma: Fix DMA Rx completion race" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. Possible dependencies: 31352811e13d ("serial: 8250_dma: Fix DMA Rx completion race") 56dc5074cbec ("serial: 8250_dma: Rearm DMA Rx if more data is pending") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 31352811e13dc2313f101b890fd4b1ce760b5fe7 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen(a)linux.intel.com> Date: Mon, 30 Jan 2023 13:48:40 +0200 Subject: [PATCH] serial: 8250_dma: Fix DMA Rx completion race MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit __dma_rx_complete() is called from two places: - Through the DMA completion callback dma_rx_complete() - From serial8250_rx_dma_flush() after IIR_RLSI or IIR_RX_TIMEOUT The former does not hold port's lock during __dma_rx_complete() which allows these two to race and potentially insert the same data twice. Extend port's lock coverage in dma_rx_complete() to prevent the race and check if the DMA Rx is still pending completion before calling into __dma_rx_complete(). Reported-by: Gilles BULOZ <gilles.buloz(a)kontron.com> Tested-by: Gilles BULOZ <gilles.buloz(a)kontron.com> Fixes: 9ee4b83e51f7 ("serial: 8250: Add support for dmaengine") Cc: stable(a)vger.kernel.org Signed-off-by: Ilpo Järvinen <ilpo.jarvinen(a)linux.intel.com> Link: https://lore.kernel.org/r/20230130114841.25749-2-ilpo.jarvinen@linux.intel.… Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c index 37d6af2ec427..5594883a96f8 100644 --- a/drivers/tty/serial/8250/8250_dma.c +++ b/drivers/tty/serial/8250/8250_dma.c @@ -62,9 +62,14 @@ static void dma_rx_complete(void *param) struct uart_8250_dma *dma = p->dma; unsigned long flags; - __dma_rx_complete(p); - spin_lock_irqsave(&p->port.lock, flags); + if (dma->rx_running) + __dma_rx_complete(p); + + /* + * Cannot be combined with the previous check because __dma_rx_complete() + * changes dma->rx_running. + */ if (!dma->rx_running && (serial_lsr_in(p) & UART_LSR_DR)) p->dma->rx_dma(p); spin_unlock_irqrestore(&p->port.lock, flags);

2 years, 2 months

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FAILED: patch "[PATCH] serial: 8250_dma: Fix DMA Rx completion race" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. Possible dependencies: 31352811e13d ("serial: 8250_dma: Fix DMA Rx completion race") 56dc5074cbec ("serial: 8250_dma: Rearm DMA Rx if more data is pending") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 31352811e13dc2313f101b890fd4b1ce760b5fe7 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen(a)linux.intel.com> Date: Mon, 30 Jan 2023 13:48:40 +0200 Subject: [PATCH] serial: 8250_dma: Fix DMA Rx completion race MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit __dma_rx_complete() is called from two places: - Through the DMA completion callback dma_rx_complete() - From serial8250_rx_dma_flush() after IIR_RLSI or IIR_RX_TIMEOUT The former does not hold port's lock during __dma_rx_complete() which allows these two to race and potentially insert the same data twice. Extend port's lock coverage in dma_rx_complete() to prevent the race and check if the DMA Rx is still pending completion before calling into __dma_rx_complete(). Reported-by: Gilles BULOZ <gilles.buloz(a)kontron.com> Tested-by: Gilles BULOZ <gilles.buloz(a)kontron.com> Fixes: 9ee4b83e51f7 ("serial: 8250: Add support for dmaengine") Cc: stable(a)vger.kernel.org Signed-off-by: Ilpo Järvinen <ilpo.jarvinen(a)linux.intel.com> Link: https://lore.kernel.org/r/20230130114841.25749-2-ilpo.jarvinen@linux.intel.… Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c index 37d6af2ec427..5594883a96f8 100644 --- a/drivers/tty/serial/8250/8250_dma.c +++ b/drivers/tty/serial/8250/8250_dma.c @@ -62,9 +62,14 @@ static void dma_rx_complete(void *param) struct uart_8250_dma *dma = p->dma; unsigned long flags; - __dma_rx_complete(p); - spin_lock_irqsave(&p->port.lock, flags); + if (dma->rx_running) + __dma_rx_complete(p); + + /* + * Cannot be combined with the previous check because __dma_rx_complete() + * changes dma->rx_running. + */ if (!dma->rx_running && (serial_lsr_in(p) & UART_LSR_DR)) p->dma->rx_dma(p); spin_unlock_irqrestore(&p->port.lock, flags);

2 years, 2 months

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FAILED: patch "[PATCH] serial: 8250_dma: Fix DMA Rx completion race" failed to apply to 6.1-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. Possible dependencies: 31352811e13d ("serial: 8250_dma: Fix DMA Rx completion race") 56dc5074cbec ("serial: 8250_dma: Rearm DMA Rx if more data is pending") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 31352811e13dc2313f101b890fd4b1ce760b5fe7 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen(a)linux.intel.com> Date: Mon, 30 Jan 2023 13:48:40 +0200 Subject: [PATCH] serial: 8250_dma: Fix DMA Rx completion race MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit __dma_rx_complete() is called from two places: - Through the DMA completion callback dma_rx_complete() - From serial8250_rx_dma_flush() after IIR_RLSI or IIR_RX_TIMEOUT The former does not hold port's lock during __dma_rx_complete() which allows these two to race and potentially insert the same data twice. Extend port's lock coverage in dma_rx_complete() to prevent the race and check if the DMA Rx is still pending completion before calling into __dma_rx_complete(). Reported-by: Gilles BULOZ <gilles.buloz(a)kontron.com> Tested-by: Gilles BULOZ <gilles.buloz(a)kontron.com> Fixes: 9ee4b83e51f7 ("serial: 8250: Add support for dmaengine") Cc: stable(a)vger.kernel.org Signed-off-by: Ilpo Järvinen <ilpo.jarvinen(a)linux.intel.com> Link: https://lore.kernel.org/r/20230130114841.25749-2-ilpo.jarvinen@linux.intel.… Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c index 37d6af2ec427..5594883a96f8 100644 --- a/drivers/tty/serial/8250/8250_dma.c +++ b/drivers/tty/serial/8250/8250_dma.c @@ -62,9 +62,14 @@ static void dma_rx_complete(void *param) struct uart_8250_dma *dma = p->dma; unsigned long flags; - __dma_rx_complete(p); - spin_lock_irqsave(&p->port.lock, flags); + if (dma->rx_running) + __dma_rx_complete(p); + + /* + * Cannot be combined with the previous check because __dma_rx_complete() + * changes dma->rx_running. + */ if (!dma->rx_running && (serial_lsr_in(p) & UART_LSR_DR)) p->dma->rx_dma(p); spin_unlock_irqrestore(&p->port.lock, flags);

2 years, 2 months

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FAILED: patch "[PATCH] serial: 8250_dma: Fix DMA Rx completion race" failed to apply to 5.15-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. Possible dependencies: 31352811e13d ("serial: 8250_dma: Fix DMA Rx completion race") 56dc5074cbec ("serial: 8250_dma: Rearm DMA Rx if more data is pending") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 31352811e13dc2313f101b890fd4b1ce760b5fe7 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen(a)linux.intel.com> Date: Mon, 30 Jan 2023 13:48:40 +0200 Subject: [PATCH] serial: 8250_dma: Fix DMA Rx completion race MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit __dma_rx_complete() is called from two places: - Through the DMA completion callback dma_rx_complete() - From serial8250_rx_dma_flush() after IIR_RLSI or IIR_RX_TIMEOUT The former does not hold port's lock during __dma_rx_complete() which allows these two to race and potentially insert the same data twice. Extend port's lock coverage in dma_rx_complete() to prevent the race and check if the DMA Rx is still pending completion before calling into __dma_rx_complete(). Reported-by: Gilles BULOZ <gilles.buloz(a)kontron.com> Tested-by: Gilles BULOZ <gilles.buloz(a)kontron.com> Fixes: 9ee4b83e51f7 ("serial: 8250: Add support for dmaengine") Cc: stable(a)vger.kernel.org Signed-off-by: Ilpo Järvinen <ilpo.jarvinen(a)linux.intel.com> Link: https://lore.kernel.org/r/20230130114841.25749-2-ilpo.jarvinen@linux.intel.… Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c index 37d6af2ec427..5594883a96f8 100644 --- a/drivers/tty/serial/8250/8250_dma.c +++ b/drivers/tty/serial/8250/8250_dma.c @@ -62,9 +62,14 @@ static void dma_rx_complete(void *param) struct uart_8250_dma *dma = p->dma; unsigned long flags; - __dma_rx_complete(p); - spin_lock_irqsave(&p->port.lock, flags); + if (dma->rx_running) + __dma_rx_complete(p); + + /* + * Cannot be combined with the previous check because __dma_rx_complete() + * changes dma->rx_running. + */ if (!dma->rx_running && (serial_lsr_in(p) & UART_LSR_DR)) p->dma->rx_dma(p); spin_unlock_irqrestore(&p->port.lock, flags);

2 years, 2 months

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FAILED: patch "[PATCH] serial: 8250_dma: Fix DMA Rx rearm race" failed to apply to 4.14-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. Possible dependencies: 57e9af7831dc ("serial: 8250_dma: Fix DMA Rx rearm race") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 57e9af7831dcf211c5c689c2a6f209f4abdf0bce Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen(a)linux.intel.com> Date: Mon, 30 Jan 2023 13:48:41 +0200 Subject: [PATCH] serial: 8250_dma: Fix DMA Rx rearm race MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit As DMA Rx can be completed from two places, it is possible that DMA Rx completes before DMA completion callback had a chance to complete it. Once the previous DMA Rx has been completed, a new one can be started on the next UART interrupt. The following race is possible (uart_unlock_and_check_sysrq_irqrestore() replaced with spin_unlock_irqrestore() for simplicity/clarity): CPU0 CPU1 dma_rx_complete() serial8250_handle_irq() spin_lock_irqsave(&port->lock) handle_rx_dma() serial8250_rx_dma_flush() __dma_rx_complete() dma->rx_running = 0 // Complete DMA Rx spin_unlock_irqrestore(&port->lock) serial8250_handle_irq() spin_lock_irqsave(&port->lock) handle_rx_dma() serial8250_rx_dma() dma->rx_running = 1 // Setup a new DMA Rx spin_unlock_irqrestore(&port->lock) spin_lock_irqsave(&port->lock) // sees dma->rx_running = 1 __dma_rx_complete() dma->rx_running = 0 // Incorrectly complete // running DMA Rx This race seems somewhat theoretical to occur for real but handle it correctly regardless. Check what is the DMA status before complething anything in __dma_rx_complete(). Reported-by: Gilles BULOZ <gilles.buloz(a)kontron.com> Tested-by: Gilles BULOZ <gilles.buloz(a)kontron.com> Fixes: 9ee4b83e51f7 ("serial: 8250: Add support for dmaengine") Cc: stable(a)vger.kernel.org Signed-off-by: Ilpo Järvinen <ilpo.jarvinen(a)linux.intel.com> Link: https://lore.kernel.org/r/20230130114841.25749-3-ilpo.jarvinen@linux.intel.… Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c index 5594883a96f8..7fa66501792d 100644 --- a/drivers/tty/serial/8250/8250_dma.c +++ b/drivers/tty/serial/8250/8250_dma.c @@ -43,15 +43,23 @@ static void __dma_rx_complete(struct uart_8250_port *p) struct uart_8250_dma *dma = p->dma; struct tty_port *tty_port = &p->port.state->port; struct dma_tx_state state; + enum dma_status dma_status; int count; - dma->rx_running = 0; - dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state); + /* + * New DMA Rx can be started during the completion handler before it + * could acquire port's lock and it might still be ongoing. Don't to + * anything in such case. + */ + dma_status = dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state); + if (dma_status == DMA_IN_PROGRESS) + return; count = dma->rx_size - state.residue; tty_insert_flip_string(tty_port, dma->rx_buf, count); p->port.icount.rx += count; + dma->rx_running = 0; tty_flip_buffer_push(tty_port); }

2 years, 2 months

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FAILED: patch "[PATCH] serial: 8250_dma: Fix DMA Rx rearm race" failed to apply to 4.19-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. Possible dependencies: 57e9af7831dc ("serial: 8250_dma: Fix DMA Rx rearm race") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 57e9af7831dcf211c5c689c2a6f209f4abdf0bce Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen(a)linux.intel.com> Date: Mon, 30 Jan 2023 13:48:41 +0200 Subject: [PATCH] serial: 8250_dma: Fix DMA Rx rearm race MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit As DMA Rx can be completed from two places, it is possible that DMA Rx completes before DMA completion callback had a chance to complete it. Once the previous DMA Rx has been completed, a new one can be started on the next UART interrupt. The following race is possible (uart_unlock_and_check_sysrq_irqrestore() replaced with spin_unlock_irqrestore() for simplicity/clarity): CPU0 CPU1 dma_rx_complete() serial8250_handle_irq() spin_lock_irqsave(&port->lock) handle_rx_dma() serial8250_rx_dma_flush() __dma_rx_complete() dma->rx_running = 0 // Complete DMA Rx spin_unlock_irqrestore(&port->lock) serial8250_handle_irq() spin_lock_irqsave(&port->lock) handle_rx_dma() serial8250_rx_dma() dma->rx_running = 1 // Setup a new DMA Rx spin_unlock_irqrestore(&port->lock) spin_lock_irqsave(&port->lock) // sees dma->rx_running = 1 __dma_rx_complete() dma->rx_running = 0 // Incorrectly complete // running DMA Rx This race seems somewhat theoretical to occur for real but handle it correctly regardless. Check what is the DMA status before complething anything in __dma_rx_complete(). Reported-by: Gilles BULOZ <gilles.buloz(a)kontron.com> Tested-by: Gilles BULOZ <gilles.buloz(a)kontron.com> Fixes: 9ee4b83e51f7 ("serial: 8250: Add support for dmaengine") Cc: stable(a)vger.kernel.org Signed-off-by: Ilpo Järvinen <ilpo.jarvinen(a)linux.intel.com> Link: https://lore.kernel.org/r/20230130114841.25749-3-ilpo.jarvinen@linux.intel.… Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c index 5594883a96f8..7fa66501792d 100644 --- a/drivers/tty/serial/8250/8250_dma.c +++ b/drivers/tty/serial/8250/8250_dma.c @@ -43,15 +43,23 @@ static void __dma_rx_complete(struct uart_8250_port *p) struct uart_8250_dma *dma = p->dma; struct tty_port *tty_port = &p->port.state->port; struct dma_tx_state state; + enum dma_status dma_status; int count; - dma->rx_running = 0; - dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state); + /* + * New DMA Rx can be started during the completion handler before it + * could acquire port's lock and it might still be ongoing. Don't to + * anything in such case. + */ + dma_status = dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state); + if (dma_status == DMA_IN_PROGRESS) + return; count = dma->rx_size - state.residue; tty_insert_flip_string(tty_port, dma->rx_buf, count); p->port.icount.rx += count; + dma->rx_running = 0; tty_flip_buffer_push(tty_port); }

2 years, 2 months

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FAILED: patch "[PATCH] serial: 8250_dma: Fix DMA Rx rearm race" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. Possible dependencies: 57e9af7831dc ("serial: 8250_dma: Fix DMA Rx rearm race") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 57e9af7831dcf211c5c689c2a6f209f4abdf0bce Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen(a)linux.intel.com> Date: Mon, 30 Jan 2023 13:48:41 +0200 Subject: [PATCH] serial: 8250_dma: Fix DMA Rx rearm race MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit As DMA Rx can be completed from two places, it is possible that DMA Rx completes before DMA completion callback had a chance to complete it. Once the previous DMA Rx has been completed, a new one can be started on the next UART interrupt. The following race is possible (uart_unlock_and_check_sysrq_irqrestore() replaced with spin_unlock_irqrestore() for simplicity/clarity): CPU0 CPU1 dma_rx_complete() serial8250_handle_irq() spin_lock_irqsave(&port->lock) handle_rx_dma() serial8250_rx_dma_flush() __dma_rx_complete() dma->rx_running = 0 // Complete DMA Rx spin_unlock_irqrestore(&port->lock) serial8250_handle_irq() spin_lock_irqsave(&port->lock) handle_rx_dma() serial8250_rx_dma() dma->rx_running = 1 // Setup a new DMA Rx spin_unlock_irqrestore(&port->lock) spin_lock_irqsave(&port->lock) // sees dma->rx_running = 1 __dma_rx_complete() dma->rx_running = 0 // Incorrectly complete // running DMA Rx This race seems somewhat theoretical to occur for real but handle it correctly regardless. Check what is the DMA status before complething anything in __dma_rx_complete(). Reported-by: Gilles BULOZ <gilles.buloz(a)kontron.com> Tested-by: Gilles BULOZ <gilles.buloz(a)kontron.com> Fixes: 9ee4b83e51f7 ("serial: 8250: Add support for dmaengine") Cc: stable(a)vger.kernel.org Signed-off-by: Ilpo Järvinen <ilpo.jarvinen(a)linux.intel.com> Link: https://lore.kernel.org/r/20230130114841.25749-3-ilpo.jarvinen@linux.intel.… Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c index 5594883a96f8..7fa66501792d 100644 --- a/drivers/tty/serial/8250/8250_dma.c +++ b/drivers/tty/serial/8250/8250_dma.c @@ -43,15 +43,23 @@ static void __dma_rx_complete(struct uart_8250_port *p) struct uart_8250_dma *dma = p->dma; struct tty_port *tty_port = &p->port.state->port; struct dma_tx_state state; + enum dma_status dma_status; int count; - dma->rx_running = 0; - dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state); + /* + * New DMA Rx can be started during the completion handler before it + * could acquire port's lock and it might still be ongoing. Don't to + * anything in such case. + */ + dma_status = dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state); + if (dma_status == DMA_IN_PROGRESS) + return; count = dma->rx_size - state.residue; tty_insert_flip_string(tty_port, dma->rx_buf, count); p->port.icount.rx += count; + dma->rx_running = 0; tty_flip_buffer_push(tty_port); }

2 years, 2 months

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Linux-stable-mirror February 2023