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authorFelix Fietkau <nbd@nbd.name>2016-12-22 08:31:34 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-01-12 11:51:24 +0100
commit732dbf3a6104a3abfcfcd066dcaf89e5054ce009 (patch)
tree7bb0dec3e05e2f61365c005e34e536a7d74bfce4
parent552df698e9e88b580039ca715e1b5ad34b6e130b (diff)
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 <john@phrozen.org> Signed-off-by: Felix Fietkau <nbd@nbd.name> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--include/linux/serial_core.h2
-rw-r--r--lib/Kconfig.debug10
2 files changed, 11 insertions, 1 deletions
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