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>
This commit is contained in:
Felix Fietkau 2016-12-22 08:31:34 +01:00 committed by Greg Kroah-Hartman
parent 552df698e9
commit 732dbf3a61
2 changed files with 11 additions and 1 deletions

View File

@ -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)
{

View File

@ -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