From: Emily Shaffer <emilyshaffer@google.com>
To: "Randall S. Becker" <rsbecker@nexbridge.com>
Cc: git@vger.kernel.org,
"'Ævar Arnfjörð Bjarmason'" <avarab@gmail.com>,
"'Junio C Hamano'" <gitster@pobox.com>,
"'Jeff Hostetler'" <git@jeffhostetler.com>,
"'Bagas Sanjaya'" <bagasdotme@gmail.com>
Subject: Re: [PATCH v5] tr2: log parent process name
Date: Wed, 9 Jun 2021 13:17:20 -0700 [thread overview]
Message-ID: <YMEh0P3sVM8qMZji@google.com> (raw)
In-Reply-To: <023701d75cb7$1ff995a0$5fecc0e0$@nexbridge.com>
On Tue, Jun 08, 2021 at 06:39:15PM -0400, Randall S. Becker wrote:
> On June 8, 2021 6:25 PM, Emily Shaffer wrote"
> >> We are probably going to have to discuss this one at more length. On
> >> NonStop, in some cases, I have access to the program arguments of the
> >> parent (rather like ps -ef) in POSIX-land, but not from the other
> >> personality. I do have access to the program object name, in both
> >> sides, although if someone replaces the object - which is not actually
> >> possible for a running program, but a rename is - the object may end
> >> up being somewhat meaningless or mangled. My suspicion is that I'm
> >> going to have to supply different things for the two personalities,
> >> but I'm not sure what as of yet.
> >
> >I guess I'm having trouble understanding - it sounds like you're
> >describing one process with a graph of ancestry instead of a line.
> >Does that mean we shouldn't be tracing the ancestry the way we are?
>
> It's more like this (g = Guardian, p=Posix, for illustration), for a
> typical interactive situation coming from the non-POSIX side):
>
> gMonitor -> gAncestor1 -> gAncestor2 -> pAncestor3 (/bin/sh) -> git
>
> And when started from an SSH window:
>
> gMonitor -> gAncestor1 (SSH) -> pAncestor2 (/bin/sh) -> git
>
> I can get the program object name from any of the above, and the pid
> from a POSIX process, or the name (or cpu and process number) of a
> Guardian process. In the case of POSIX, obtaining program arguments
> may be possible. An ancestor, as with Linux, can have multiple
> children in a tree but a child can only have one parent - well,
> technically one at a time anyway because there are some funky
> exceptions where a child can adopt a different parent in
> Guardian-land. In both cases, I can get the program object file of the
> process (like /usr/local/bin/git), but if someone renames git because
> an install happened during a long-running operation, like git gc
> --aggressive, the object may be named something else, like
> /usr/local/bin/ZZLDAG01, for argument sake).
Interesting. One thing that might be helpful (if you don't care about
the later name, since it looks like it might be junk) is that
trace2_collect_process_info() provides some hint about when it was
invoked, via the 'enum trace2_process_info_reason' arg. So if you're
worried about a long-running process being renamed, the
TRACE2_PROCESS_INFO_STARTUP reason happens very early in common-main.c.
(And you could capture info like "the name changed later" at
TRACE2_PROCESS_INFO_EXIT if you wanted.)
> I'm not sure any of this is really relevant, but describes some of
> what is possible. It also might be useful to pull out the tty that the
> process was running on. That is easy to get if the terminal is still
> connected. I think that particular bit of information might be very
> useful, as well as user information.
>
> -Randall
>
(I don't have much insight into what would or wouldn't be useful to log
here in your case, but I will say that it all sounds very cool and I
appreciate your thorough explanation.)
- Emily
next prev parent reply other threads:[~2021-06-09 20:18 UTC|newest]
Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-07 0:29 [PATCH] tr2: log parent process name Emily Shaffer
2021-05-07 3:25 ` Bagas Sanjaya
2021-05-07 17:09 ` Emily Shaffer
2021-05-10 12:29 ` Ævar Arnfjörð Bjarmason
2021-05-11 21:31 ` Junio C Hamano
2021-05-14 22:06 ` Emily Shaffer
2021-05-16 3:48 ` Junio C Hamano
2021-05-17 20:17 ` Emily Shaffer
2021-05-11 17:28 ` Jeff Hostetler
2021-05-14 22:07 ` Emily Shaffer
2021-05-20 21:05 ` [PATCH v2] " Emily Shaffer
2021-05-20 21:36 ` Randall S. Becker
2021-05-20 23:23 ` Emily Shaffer
2021-05-21 13:20 ` Randall S. Becker
2021-05-21 16:24 ` Randall S. Becker
2021-05-21 2:09 ` Junio C Hamano
2021-05-21 19:02 ` Emily Shaffer
2021-05-21 23:22 ` Junio C Hamano
2021-05-24 18:37 ` Emily Shaffer
2021-05-21 19:15 ` Jeff Hostetler
2021-05-21 20:05 ` Emily Shaffer
2021-05-21 20:23 ` Randall S. Becker
2021-05-22 11:18 ` Jeff Hostetler
2021-05-24 23:33 ` Ævar Arnfjörð Bjarmason
2021-05-24 20:10 ` [PATCH v3] " Emily Shaffer
2021-05-24 20:49 ` Emily Shaffer
2021-05-25 3:54 ` Junio C Hamano
2021-05-25 13:33 ` Randall S. Becker
2021-06-08 18:58 ` [PATCH v4] " Emily Shaffer
2021-06-08 20:56 ` Emily Shaffer
2021-06-08 22:10 ` [PATCH v5] " Emily Shaffer
2021-06-08 22:16 ` Randall S. Becker
2021-06-08 22:24 ` Emily Shaffer
2021-06-08 22:39 ` Randall S. Becker
2021-06-09 20:17 ` Emily Shaffer [this message]
2021-06-16 8:42 ` Junio C Hamano
2021-06-28 16:45 ` Jeff Hostetler
2021-06-29 23:51 ` Emily Shaffer
2021-06-30 6:10 ` Ævar Arnfjörð Bjarmason
2021-07-22 0:21 ` Emily Shaffer
2021-07-22 1:27 ` [PATCH v6 0/2] " Emily Shaffer
2021-07-22 1:27 ` [PATCH v6 1/2] tr2: make process info collection platform-generic Emily Shaffer
2021-08-02 9:34 ` Ævar Arnfjörð Bjarmason
2021-07-22 1:27 ` [PATCH v6 2/2] tr2: log parent process name Emily Shaffer
2021-07-22 21:02 ` Junio C Hamano
2021-08-02 9:38 ` Ævar Arnfjörð Bjarmason
2021-08-02 12:45 ` Ævar Arnfjörð Bjarmason
2021-08-02 10:22 ` Ævar Arnfjörð Bjarmason
2021-08-02 12:47 ` Ævar Arnfjörð Bjarmason
2021-08-02 15:23 ` Jeff Hostetler
2021-08-02 16:10 ` Randall S. Becker
2021-08-02 18:41 ` Ævar Arnfjörð Bjarmason
2021-08-25 23:19 ` [PATCH 0/6] tr2: plug memory leaks + logic errors + Win32 & Linux feature parity Ævar Arnfjörð Bjarmason
2021-08-25 23:19 ` [PATCH 1/6] tr2: remove NEEDSWORK comment for "non-procfs" implementations Ævar Arnfjörð Bjarmason
2021-08-25 23:19 ` [PATCH 2/6] tr2: clarify TRACE2_PROCESS_INFO_EXIT comment under Linux Ævar Arnfjörð Bjarmason
2021-08-25 23:19 ` [PATCH 3/6] tr2: stop leaking "thread_name" memory Ævar Arnfjörð Bjarmason
2021-08-26 3:09 ` Taylor Blau
2021-08-25 23:19 ` [PATCH 4/6] tr2: fix memory leak & logic error in 2f732bf15e6 Ævar Arnfjörð Bjarmason
2021-08-26 3:21 ` Taylor Blau
2021-08-25 23:19 ` [PATCH 5/6] tr2: do compiler enum check in trace2_collect_process_info() Ævar Arnfjörð Bjarmason
2021-08-26 3:23 ` Taylor Blau
2021-08-25 23:19 ` [PATCH 6/6] tr2: log N parent process names on Linux Ævar Arnfjörð Bjarmason
2021-08-25 23:49 ` Eric Sunshine
2021-08-26 4:07 ` Taylor Blau
2021-08-26 12:24 ` "I don't know what the author meant by that..." (was "Re: [PATCH 6/6] tr2: log N parent process names on Linux") Ævar Arnfjörð Bjarmason
2021-08-26 12:22 ` [PATCH v2 0/6] tr2: plug memory leaks + logic errors + Win32 & Linux feature parity Ævar Arnfjörð Bjarmason
2021-08-26 12:22 ` [PATCH v2 1/6] tr2: remove NEEDSWORK comment for "non-procfs" implementations Ævar Arnfjörð Bjarmason
2021-08-26 12:22 ` [PATCH v2 2/6] tr2: clarify TRACE2_PROCESS_INFO_EXIT comment under Linux Ævar Arnfjörð Bjarmason
2021-08-26 12:22 ` [PATCH v2 3/6] tr2: stop leaking "thread_name" memory Ævar Arnfjörð Bjarmason
2021-08-26 12:22 ` [PATCH v2 4/6] tr2: fix memory leak & logic error in 2f732bf15e6 Ævar Arnfjörð Bjarmason
2021-08-26 15:58 ` Eric Sunshine
2021-08-26 16:42 ` Junio C Hamano
2021-08-26 12:22 ` [PATCH v2 5/6] tr2: do compiler enum check in trace2_collect_process_info() Ævar Arnfjörð Bjarmason
2021-08-26 12:22 ` [PATCH v2 6/6] tr2: log N parent process names on Linux Ævar Arnfjörð Bjarmason
2021-08-26 22:38 ` [PATCH v2 0/6] tr2: plug memory leaks + logic errors + Win32 & Linux feature parity Taylor Blau
2021-08-27 8:02 ` [PATCH v3 " Ævar Arnfjörð Bjarmason
2021-08-27 8:02 ` [PATCH v3 1/6] tr2: remove NEEDSWORK comment for "non-procfs" implementations Ævar Arnfjörð Bjarmason
2021-08-27 8:02 ` [PATCH v3 2/6] tr2: clarify TRACE2_PROCESS_INFO_EXIT comment under Linux Ævar Arnfjörð Bjarmason
2021-08-27 8:02 ` [PATCH v3 3/6] tr2: stop leaking "thread_name" memory Ævar Arnfjörð Bjarmason
2021-08-27 8:02 ` [PATCH v3 4/6] tr2: leave the parent list empty upon failure & don't leak memory Ævar Arnfjörð Bjarmason
2021-08-27 8:02 ` [PATCH v3 5/6] tr2: do compiler enum check in trace2_collect_process_info() Ævar Arnfjörð Bjarmason
2021-08-27 8:02 ` [PATCH v3 6/6] tr2: log N parent process names on Linux Ævar Arnfjörð Bjarmason
2021-08-31 0:17 ` [PATCH v3 0/6] tr2: plug memory leaks + logic errors + Win32 & Linux feature parity Taylor Blau
2021-08-02 10:30 ` [PATCH v6 2/2] tr2: log parent process name Ævar Arnfjörð Bjarmason
2021-08-02 16:24 ` Junio C Hamano
2021-08-02 18:42 ` Ævar Arnfjörð Bjarmason
2021-07-22 16:59 ` [PATCH v6 0/2] " Jeff Hostetler
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