From 732dbf3a6104a3abfcfcd066dcaf89e5054ce009 Mon Sep 17 00:00:00 2001 From: Felix Fietkau Date: Thu, 22 Dec 2016 08:31:34 +0100 Subject: [PATCH] serial: do not accept sysrq characters via serial port many embedded boards have a disconnected TTL level serial which can generate some garbage that can lead to spurious false sysrq detects. Signed-off-by: John Crispin Signed-off-by: Felix Fietkau Signed-off-by: Greg Kroah-Hartman --- include/linux/serial_core.h | 2 +- lib/Kconfig.debug | 10 ++++++++++ 2 files changed, 11 insertions(+), 1 deletion(-) diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index 5def8e830fb0..58484fb35cc8 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -450,7 +450,7 @@ extern void uart_handle_cts_change(struct uart_port *uport, extern void uart_insert_char(struct uart_port *port, unsigned int status, unsigned int overrun, unsigned int ch, unsigned int flag); -#ifdef SUPPORT_SYSRQ +#if defined(SUPPORT_SYSRQ) && defined(CONFIG_MAGIC_SYSRQ_SERIAL) static inline int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch) { diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index b06848a104e6..9fa4e6eb1fe3 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -416,6 +416,16 @@ config MAGIC_SYSRQ_DEFAULT_ENABLE This may be set to 1 or 0 to enable or disable them all, or to a bitmask as described in Documentation/sysrq.txt. +config MAGIC_SYSRQ_SERIAL + bool "Enable magic SysRq key over serial" + depends on MAGIC_SYSRQ + default y + help + Many embedded boards have a disconnected TTL level serial which can + generate some garbage that can lead to spurious false sysrq detects. + This option allows you to decide whether you want to enable the + magic SysRq key. + config DEBUG_KERNEL bool "Kernel debugging" help -- GitLab