Re: [PATCH] man ptrace: add extended description of various ptrace quirks

From: Michael Kerrisk
Date: Mon Oct 03 2011 - 01:35:43 EST

Hi Denys,

On Fri, Sep 30, 2011 at 4:28 PM, Denys Vlasenko
<vda.linux@xxxxxxxxxxxxxx> wrote:
> On Thu, Sep 29, 2011 at 9:08 PM, Michael Kerrisk <mtk.manpages@xxxxxxxxx> wrote:
>> So, I took your patch, and then did a global edit of the page to fix
>> various pieces (in the existing text, as well as do some language
>> clean-ups for the new text). In the process, I found a number of
>> pieces that are still unclear (some in the old text, some in your new
>> text). I also made some changes to your text that I'd like you to
>> check. I've marked each of these with FIXME below. Could you please
>> take a look at the FIXMEs, and write me a comment for each of these.
>> (I appreciate that in some cases, especially for the existing text,
>> you may not have a handy answer Denys, but if you (and others) can
>> give any help, that would be great.)
>> Rather than you writing a new patch to this version of the page, I
>> think it might be easiest if you just replied to the FIXMEs inline
>> below, then I can revise the page in the light of your comments.
>       Another group of commands makes the ptrace-stopped  tracee  run.   They
>       have the form:
>           ptrace(PTRACE_cmd, pid, 0, sig);
> Cosmetics: cmd is, of course, CONT, DETACH,..., not PTRACE_CONT,

Yes. But what I did to fix is change the ptrace call to:

ptrace(cmd, pid, 0, sig);

(Having these constants shown without the "PTRACE_" prefix is a little

>       If the tracee  is
>       in  signal-delivery-stop,  sig  is  the signal to be injected (if it is
>       nonzero).  Otherwise, sig may be ignored.  (Recommended practice is  to
>       always pass 0 in these cases.)
> Looks like (my) text in last sentence is confusing. I meant:
> "If you are resterting thracee from a ptrace-stop other than
> signal-delivery-stop, recommended practice is  to always pass
> sig == 0".

Okay -- I made that change.



Michael Kerrisk
Linux man-pages maintainer;
Author of "The Linux Programming Interface";
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at