From: Greg Kroah-Hartman Date: Mon, 1 Jul 2013 18:45:53 +0000 (-0700) Subject: 3.0-stable patches X-Git-Tag: v3.9.9~6 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=5a8fb0b6b3ab583abddd3806a843614c227f786b;p=thirdparty%2Fkernel%2Fstable-queue.git 3.0-stable patches added patches: pch_uart-fix-a-deadlock-when-pch_uart-as-console.patch --- diff --git a/queue-3.0/pch_uart-fix-a-deadlock-when-pch_uart-as-console.patch b/queue-3.0/pch_uart-fix-a-deadlock-when-pch_uart-as-console.patch new file mode 100644 index 00000000000..b17cbe7a3c1 --- /dev/null +++ b/queue-3.0/pch_uart-fix-a-deadlock-when-pch_uart-as-console.patch @@ -0,0 +1,81 @@ +From 384e301e3519599b000c1a2ecd938b533fc15d85 Mon Sep 17 00:00:00 2001 +From: Liang Li +Date: Sat, 19 Jan 2013 17:52:10 +0800 +Subject: pch_uart: fix a deadlock when pch_uart as console + +From: Liang Li + +commit 384e301e3519599b000c1a2ecd938b533fc15d85 upstream. + +When we use pch_uart as system console like 'console=ttyPCH0,115200', +then 'send break' to it. We'll encounter the deadlock on a cpu/core, +with interrupts disabled on the core. When we happen to have all irqs +affinity to cpu0 then the deadlock on cpu0 actually deadlock whole +system. + +In pch_uart_interrupt, we have spin_lock_irqsave(&priv->lock, flags) +then call pch_uart_err_ir when break is received. Then the call to +dev_err would actually call to pch_console_write then we'll run into +another spin_lock(&priv->lock), with interrupts disabled. + +So in the call sequence lead by pch_uart_interrupt, we should be +carefully to call functions that will 'print message to console' only +in case the uart port is not being used as serial console. + +Signed-off-by: Liang Li +Cc: Yijing Wang +Signed-off-by: Greg Kroah-Hartman + +--- + drivers/tty/serial/pch_uart.c | 33 ++++++++++++++++++++++++--------- + 1 file changed, 24 insertions(+), 9 deletions(-) + +--- a/drivers/tty/serial/pch_uart.c ++++ b/drivers/tty/serial/pch_uart.c +@@ -935,22 +935,37 @@ static unsigned int dma_handle_tx(struct + static void pch_uart_err_ir(struct eg20t_port *priv, unsigned int lsr) + { + u8 fcr = ioread8(priv->membase + UART_FCR); ++ struct uart_port *port = &priv->port; ++ struct tty_struct *tty = tty_port_tty_get(&port->state->port); ++ char *error_msg[5] = {}; ++ int i = 0; + + /* Reset FIFO */ + fcr |= UART_FCR_CLEAR_RCVR; + iowrite8(fcr, priv->membase + UART_FCR); + + if (lsr & PCH_UART_LSR_ERR) +- dev_err(&priv->pdev->dev, "Error data in FIFO\n"); ++ error_msg[i++] = "Error data in FIFO\n"; + +- if (lsr & UART_LSR_FE) +- dev_err(&priv->pdev->dev, "Framing Error\n"); +- +- if (lsr & UART_LSR_PE) +- dev_err(&priv->pdev->dev, "Parity Error\n"); +- +- if (lsr & UART_LSR_OE) +- dev_err(&priv->pdev->dev, "Overrun Error\n"); ++ if (lsr & UART_LSR_FE) { ++ port->icount.frame++; ++ error_msg[i++] = " Framing Error\n"; ++ } ++ ++ if (lsr & UART_LSR_PE) { ++ port->icount.parity++; ++ error_msg[i++] = " Parity Error\n"; ++ } ++ ++ if (lsr & UART_LSR_OE) { ++ port->icount.overrun++; ++ error_msg[i++] = " Overrun Error\n"; ++ } ++ ++ if (tty == NULL) { ++ for (i = 0; error_msg[i] != NULL; i++) ++ dev_err(&priv->pdev->dev, error_msg[i]); ++ } + } + + static irqreturn_t pch_uart_interrupt(int irq, void *dev_id) diff --git a/queue-3.0/series b/queue-3.0/series index 608723c1820..398cc97f027 100644 --- a/queue-3.0/series +++ b/queue-3.0/series @@ -5,3 +5,4 @@ dlci-validate-the-net-device-in-dlci_del.patch perf-disable-monitoring-on-setuid-processes-for-regular-users.patch ubifs-prepare-to-fix-a-horrid-bug.patch ubifs-fix-a-horrid-bug.patch +pch_uart-fix-a-deadlock-when-pch_uart-as-console.patch