root@am437x:~# insmod kgdboe.ko kgdboe=@/,@128.224.162.196/ netpoll: kgdboe: local port 6443 netpoll: kgdboe: local IPv4 address 0.0.0.0 netpoll: kgdboe: interface 'eth0' netpoll: kgdboe: remote port 6442 netpoll: kgdboe: remote IPv4 address 128.224.162.196 netpoll: kgdboe: remote ethernet address ff:ff:ff:ff:ff:ff netpoll: kgdboe: local IP 128.224.162.118 kgdb: Registered I/O driver kgdboe. root@am437x:~# ls =============================== [ INFO: suspicious RCU usage. ] 3.10.38-ltsi-WR6.0.0.0_standard #8 Not tainted ------------------------------- /build/build-ti-am437x-test-std/bitbake_build/tmp/work/ti_am437x-wrs-linux-gnueabi/linux-windriver/3.10-r0/linux/kernel/pid.c:448 find_task_by_pid_ns() needs rcu_ read_lock() protection! other info that might help us debug this: rcu_scheduler_active = 1, debug_locks = 0 2 locks held by sh/632: #0: (dbg_master_lock){......}, at: [<c00bbf44>] kgdb_handle_exception+0x2d0/0x7c0 #1: (dbg_slave_lock){..-...}, at: [<c00bc218>] kgdb_handle_exception+0x5a4/0x7c0 stack backtrace: CPU: 0 PID: 632 Comm: sh Not tainted 3.10.38-ltsi-WR6.0.0.0_standard #8 [<c0016398>] (unwind_backtrace+0x0/0x100) from [<c0012adc>] (show_stack+0x20/0x24) [<c0012adc>] (show_stack+0x20/0x24) from [<c0718ca8>] (dump_stack+0x24/0x28) [<c0718ca8>] (dump_stack+0x24/0x28) from [<c0098148>] (lockdep_rcu_suspicious+0xf0/0x104) [<c0098148>] (lockdep_rcu_suspicious+0xf0/0x104) from [<c006a924>] (find_task_by_pid_ns+0x8c/0xa8) [<c006a924>] (find_task_by_pid_ns+0x8c/0xa8) from [<c00bc994>] (getthread.isra.4+0x3c/0x90) [<c00bc994>] (getthread.isra.4+0x3c/0x90) from [<c00bdddc>] (gdb_serial_stub+0xf00/0x11d8) [<c00bdddc>] (gdb_serial_stub+0xf00/0x11d8) from [<c00bc198>] (kgdb_handle_exception+0x524/0x7c0) [<c00bc198>] (kgdb_handle_exception+0x524/0x7c0) from [<c0015608>] (kgdb_brk_fn+0x58/0xa4) [<c0015608>] (kgdb_brk_fn+0x58/0xa4) from [<c00082f8>] (do_undefinstr+0xf8/0x1b8) [<c00082f8>] (do_undefinstr+0xf8/0x1b8) from [<c071f5b0>] (__und_svc_finish+0x0/0x30) Exception stack(0xecc85f08 to 0xecc85f50) 5f00: 01200011 00000000 00000000 00000000 b6fb43f8 00000000 5f20: b6fb4390 00000078 c000e648 ecc84000 00000000 ecc85fa4 b6fb43f8 ecc85f90 5f40: c0041ab8 c0041594 800d0013 ffffffff [<c071f5b0>] (__und_svc_finish+0x0/0x30) from [<c0041594>] (do_fork+0x0/0x448) kgdboe.ko