prfi:

I've tried to debug some code using GDB server on target device (Ubiquity AP AC PRO MIPS32r2) and I've found that it doesn't work.

I'm using std command to run GDB server: "gdbserver :9000 <application_to_debug>" and I always get "sigprocmask: Invalid argument.".

I've made short investigation to find root cause of this problem and it seems that problem is located in GDB in file: "gdb/common/signals-state-save-restore.c" in line "res = sigprocmask (0, NULL, &original_signal_mask);". According to linux kernel documentation function "sigprocmask" always return "-EINVAL" when it is called with invalid "how" argument (in this case how == 0). I've fixed GDB by removing "if" statement that checks if "res < 0". After this operation GDB server works properly.

LEDE commit: 08371a2
GDB version: 7.12.1