On 11/28, Dmitry V. Levin wrote: > > +/* > + * These values are stored in task->ptrace_message by tracehook_report_syscall_* > + * to describe current syscall-stop. > + * > + * Values for these constants are chosen so that they do not appear > + * in task->ptrace_message by other means. > + */ > +#define PTRACE_EVENTMSG_SYSCALL_ENTRY 0x80000000U > +#define PTRACE_EVENTMSG_SYSCALL_EXIT 0x90000000U Again, I do not really understand the comment... Why should we care about "do not appear in task->ptrace_message by other means" ? 2/2 should detect ptrace_report_syscall() case correctly, so we can use any numbers, say, 1 and 2? If debugger does PTRACE_GETEVENTMSG it should know how to interpet the value anyway after wait(status). Oleg.