Debugging Linux Kernel using KGDB Part4 - Enable KGDB at runtime

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Suppose, you have a scenario in which you have not enabled KGDB at boot time through kernel command line, but have compiled the kernel with the configuration required for KGDB.
CONFIG_FRAME_POINTER=y
CONFIG_KGDB=y

CONFIG_KGDB_SERIAL_CONSOLE=y

Now if you want to enable the KGDB, run the below commands on the target machine.

Step 1: Specify the serial port, plus baud rate to the kgdboc

#echo "ttyS1,115200" > /sys/module/kgdboc/parameters/kgdboc

Step 2: Run the Sysrq magic sequence

#echo g > /proc/sysrq-trigger

On the Host machine it is the same set of commands

Step1: gdb ./vmlinux
Step2: target remote /dev/ttyS1


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