On 09/15/2016 11:32 PM, AKASHI Takahiro wrote:
@@ -176,18 +183,14 @@ int kgdb_arch_handle_exception(int exception_vector, int
* over and over again.
- atomic_set(&kgdb_cpu_doing_single_step, -1);
- kgdb_single_step = 0;
This is a subtle change, but I assume it is what you intended? All the CPUs
will get released into the run state when exiting the kgdb exception handler.
You are talking about "- kgdb_single_step = 0." Right?
Do you think that there is any (negative) side effect of this change?
Not at all. The kernel debugger always skids to a stop, and it is more reliable from a
locking perspective if the other CPU threads are released while a single CPU is asked to
single step until the next "skid" for all the other CPUs.
When you do not release the other CPUs you can end up single stepping a CPU
which dead locks or never exits a lock elsewhere due to what ever it was
blocking on never getting freed from another CPU.