On 06/18/2013 05:57 PM, Denys Vlasenko wrote:
> The logic was:
>
> else if (!sigstop_expected && my_tkill(tcp->pid, SIGSTOP) <
> 0) {
> if (errno != ESRCH)
> perror_msg("detach: stopping child");
> }
> else
> sigstop_expected = 1;
>
> which, if my_tkill succeeded, was setting sigstop_expected = 1.
>
> Now if we send PTRACE_INTERRUPT, we also set sigstop_expected = 1.
>
> But there will be no SIGSTOP (unless tracee is already stopped, then yes) -
> PTRACE_INTERRUPT generates SIGTRAP-stop!
>
> I propose the attached patch.
> Sorry, Thunderbird mangles inline patches :(
+ if (error && errno != ESRCH) {
+ if (use_seize)
+ perror_msg("detach:
ptrace(PTRACE_INTERRUPT, ...)");
+ else
+ perror_msg("detach: stopping child");
+ } else {
+ sigstop_expected = 1;
+ }
Hmm, my patch sets sigstop_expected = 1 also if we got
an error, but is was ESRCH.
Which is perhaps suboptimal: we should expect a stop
only if PTRACE_INTERRUPT or tkill succeded.
Also, it is no longer sigstop_expected, but rather stop_expected,
since the stop may be not SIGSTOP.
I sent a newer version of the patch. Please let me know what you think.
(I split off and committed a trivial part of the change).
--
vda
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