Date: Fri, 16 Oct 2015 11:11:59 -0700 From: Mark Johnston <markj@freebsd.org> To: Shrikanth Kamath <shrikanth07@gmail.com> Cc: "freebsd-dtrace@freebsd.org" <freebsd-dtrace@freebsd.org> Subject: Re: Running DTrace Userland probes at times terminates traced process Message-ID: <CAMw1wOzcUgfUnXhBLtugZxAkijARxU3-Q0sJ24FPdRKZ91cUCw@mail.gmail.com> In-Reply-To: <CAEOAkMW4_Z5dcEgBU4QRxogmUswZvm0DPKeJn%2B65UJDV_NiyOg@mail.gmail.com> References: <CAEOAkMW4_Z5dcEgBU4QRxogmUswZvm0DPKeJn%2B65UJDV_NiyOg@mail.gmail.com>
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On Thu, Oct 15, 2015 at 10:53 PM, Shrikanth Kamath <shrikanth07@gmail.com> wrote: > It maybe a non issue but wanted to check with the forum, > > I am running the following dtrace one liner on the login process > > root@bsdvm#dtrace -ln 'pid$target::*:entry' -p <pid of login> > > root@bsdvm:~ # ps > PID TT STAT TIME COMMAND > 1820 u0 Ss 0:00.02 login [pam] (login) > ... > > root@bsdvm:~ # uname -a > FreeBSD bsdvm 10.2-STABLE FreeBSD 10.2-STABLE #0 r286878: Tue Aug 18 > 22:14:16 UTC 2015 > root@releng1.nyi.freebsd.org:/usr/obj/usr/src/sys/GENERIC i386 > > > But before it can finish listing all the probes I issue a CTRL-C and > thereby stopping dtrace. This results in terminating the login > process. > > When I ran ktrace on dtrace I see it does a PT_ATTACH but since I do > not allow to run it to completion and terminate early it fails to do a > clean PT_DETACH thereby terminating the traced process. > > May not be an issue if we don't kill DTrace after it has done a PT_ATTACH... This has been fixed in head: dtrace(1) now detaches from the child process(es) before exiting when it receives a signal in -l mode. For some reason I haven't merged the change to stable/10 yet - sorry about that. I'll be sure to MFC the change in the next day or so.
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