Messages in this thread | | | Date | Fri, 10 Jan 2014 14:58:02 +0100 | From | Oleg Nesterov <> | Subject | Re: [RFC/PATCH] Implement new PTRACE_EVENT_SYSCALL_{ENTER,EXIT} |
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On 01/09, Pedro Alves wrote: > > On 01/07/2014 03:30 PM, Oleg Nesterov wrote: > > > > This way PTRACE_O_SYSCALL_* will work like other ptrace options which > > ask to report an event. > > +10^6. With PTRACE_SYSCALL/sysgood, we don't have a way to trace > syscalls when single-stepping, which isn't much of a problem for > strace, but of course is for GDB. That is one of the things the > new API should definitely sort out.
Hmm. I think this is a good point, but this needs more discussion.
So suppose that gdb does ptrace(PTRACE_SINGLESTEP) and the tracee executes the "syscall" insn. What it should report?
syscall-entry looks obvious, PTRACE_EVENT_SYSCALL_ENTER should be reported if PTRACE_O_SYSCALL_ENTER was set.
But what should syscall-exit do? Should it still report SIGSEGV as it currently does, or should it report _SYSCALL_EXIT instead (if PTRACE_O_SYSCALL_EXIT of course), or should it report both?
Oleg.
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