From: David Howells <dhowells@redhat.com>
To: Markus Gutschke <markus@google.com>
Cc: "Kawai, Hidehiro" <hidehiro.kawai.ez@hitachi.com>,
Andrew Morton <akpm@osdl.org>,
kernel list <linux-kernel@vger.kernel.org>,
Pavel Machek <pavel@ucw.cz>, Robin Holt <holt@sgi.com>,
Alan Cox <alan@lxorguk.ukuu.org.uk>,
Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
sugita <yumiko.sugita.yf@hitachi.com>,
Satoshi OSHIMA <soshima@redhat.com>
Subject: Re: [PATCH 0/4] coredump: core dump masking support v3
Date: Mon, 26 Feb 2007 11:49:14 +0000 [thread overview]
Message-ID: <2910.1172490554@redhat.com> (raw)
In-Reply-To: <45E09989.5070604@google.com>
Markus Gutschke <markus@google.com> wrote:
> > How does it work when you can't actually get back to userspace to have
> > userspace do the coredump? You still have to handle the userspace
> > equivalents of double/triple faults.
>
> My experience shows that there are only very rare occurrences of situations
> where you cannot get back into userspace to do the coredump, and the
> coredumper tries very hard never to cause additional faults.
So what? If they can occur, you have to handle them.
> While I am sure you could construct scenarios where this would happen,
> realistically the only one I have run into were stack overflows, and they can
> be handled by carefully setting up an alternate stack for signal handlers --
> just make sure the entire stack is already dirtied before you run out of
> memory (or, turn of overcommitting).
Duff SIGSEGV or SIGBUS signal handlers are just as realistic. All that takes
is for someone to make a programming error. Remember: error paths are the
least frequently tested.
And any time you say "by carefully setting up" you can guarantee someone's
going to do it wrong.
David
next prev parent reply other threads:[~2007-02-26 11:49 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-02-16 13:34 [PATCH 0/4] coredump: core dump masking support v3 Kawai, Hidehiro
2007-02-16 13:39 ` [PATCH 1/4] coredump: add an interface to control the core dump routine Kawai, Hidehiro
2007-02-16 13:40 ` [PATCH 2/4] coredump: ELF: enable to omit anonymous shared memory Kawai, Hidehiro
2007-02-16 13:41 ` [PATCH 3/4] coredump: ELF-FDPIC: " Kawai, Hidehiro
2007-02-16 13:42 ` [PATCH 4/4] coredump: documentation for proc entry Kawai, Hidehiro
2007-02-16 15:05 ` [PATCH 3/4] coredump: ELF-FDPIC: enable to omit anonymous shared memory David Howells
2007-02-16 16:50 ` Robin Holt
2007-02-16 20:09 ` David Howells
2007-03-02 16:55 ` Hugh Dickins
2007-03-03 14:10 ` David Howells
2007-03-05 19:04 ` Hugh Dickins
2007-03-06 18:13 ` David Howells
2007-03-09 14:12 ` Move to unshared VMAs in NOMMU mode? David Howells
2007-03-12 20:50 ` Robin Getz
2007-03-13 10:14 ` David Howells
2007-03-15 21:20 ` Hugh Dickins
2007-03-15 22:47 ` David Howells
2007-03-19 19:23 ` Eric W. Biederman
2007-03-20 11:06 ` David Howells
2007-03-20 16:48 ` Eric W. Biederman
2007-03-20 19:12 ` David Howells
2007-03-20 19:51 ` David Howells
2007-03-21 16:11 ` David Howells
2007-03-03 14:25 ` [PATCH] NOMMU: Hide vm_mm in NOMMU mode David Howells
2007-02-20 9:45 ` [PATCH 3/4] coredump: ELF-FDPIC: enable to omit anonymous shared memory Kawai, Hidehiro
2007-02-20 10:58 ` David Howells
2007-02-20 12:56 ` Robin Holt
2007-02-21 10:00 ` Kawai, Hidehiro
2007-02-21 11:33 ` David Howells
2007-02-21 11:54 ` Robin Holt
2007-02-22 5:33 ` Kawai, Hidehiro
2007-02-22 11:47 ` David Howells
2007-02-16 15:08 ` [PATCH 0/4] coredump: core dump masking support v3 David Howells
2007-02-20 9:48 ` Kawai, Hidehiro
2007-02-24 3:32 ` Markus Gutschke
2007-02-24 11:39 ` Pavel Machek
2007-03-01 12:35 ` Kawai, Hidehiro
2007-03-01 18:16 ` Markus Gutschke
2007-02-24 10:02 ` David Howells
2007-02-24 20:01 ` Markus Gutschke
2007-02-26 11:49 ` David Howells [this message]
2007-02-26 12:01 ` Pavel Machek
2007-02-26 12:42 ` David Howells
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