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Date:      Sun, 8 Jul 2018 22:37:09 -0700
From:      Doug Hardie <bc979@lafn.org>
To:        Michael Sierchio <kudzu@tenebras.com>
Cc:        freebsd-questions <freebsd-questions@freebsd.org>
Subject:   Re: Signal 6
Message-ID:  <AF8DAD9D-8447-4BCC-9A4C-004D38E5979C@mail.sermon-archive.info>
In-Reply-To: <CAHu1Y70YSOmzvbVDQPH-5MpzW5CEBg0QaRiCyvs6%2BdDAwDhmAw@mail.gmail.com>
References:  <0D66C7A3-EBE6-475C-8360-CAFEAEA4D328@mail.sermon-archive.info> <CAHu1Y71%2Bk4aOgeMh-muxfM7qb2vCNjGsgYYyVstB=TrDto92zg@mail.gmail.com> <CAHu1Y70YSOmzvbVDQPH-5MpzW5CEBg0QaRiCyvs6%2BdDAwDhmAw@mail.gmail.com>

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> On 29 June 2018, at 08:57, Michael Sierchio <kudzu@tenebras.com> =
wrote:
>=20
> One way to find out is to register a handler for SIGABRT and print and =
flush the context.

Registering a handler is easy.  The stack is shown through backtrace().  =
However, if the backtrace is in the main code, it shows the complete =
stack.  If it is in an interrupt handler function then it only shows the =
call to backtrace.  Is there some way to give it access to the complete =
stack?

>=20
> On Fri, Jun 29, 2018 at 8:56 AM, Michael Sierchio <kudzu@tenebras.com> =
wrote:
> Are there process limits?
>=20
> malloc() will call abort() if internal structures are munged (e.g., by =
heap overflow).
>=20
> calling free() on a corrupted pointer does that reliably
>=20
> is the root partition big enough for the dump?
>=20
> =3D M
>=20
> On Fri, Jun 29, 2018 at 8:40 AM, Doug Hardie <bc979@lafn.org> wrote:
> I have a daemon process that runs forever (almost).  Something is =
killing it with a signal 6, but no core dump is done.  If I manually =
kill it with kill -6, then the log message shows core dumped and a core =
file is created.  The process has no reference to SIG_ABRT, so I suspect =
the kernel is doing the kill and is overriding the core dump.  I have =
previously encountered a similar issue where swap space was running out =
and the kernel killed this process without a core dump.  In that case =
there were quite a few messages logged about swap space issues before =
the process was killed.  There are no swap messages logged this time.
>=20
> /etc/sysctl.conf contains:
> kern.sugid_coredump=3D1
> kern.corefile=3D/crash/%N.core
>=20
> /crash is a directory in the root file system.
>=20
> Other than swap issues, when would the kernel kill a process without a =
core dump?
>=20
> -- Doug
>=20
> _______________________________________________
> freebsd-questions@freebsd.org mailing list
> https://lists.freebsd.org/mailman/listinfo/freebsd-questions
> To unsubscribe, send any mail to =
"freebsd-questions-unsubscribe@freebsd.org"
>=20
>=20
>=20
> --=20
> "Well," Brahma said, "even after ten thousand explanations, a fool is =
no wiser, but an intelligent person requires only two thousand five =
hundred."
>=20
> - The Mah=C4=81bh=C4=81rata
>=20
>=20
>=20
> --=20
> "Well," Brahma said, "even after ten thousand explanations, a fool is =
no wiser, but an intelligent person requires only two thousand five =
hundred."
>=20
> - The Mah=C4=81bh=C4=81rata




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