From: "David S. Miller" <davem@redhat.com>
To: alan@lxorguk.ukuu.org.uk
Cc: viro@math.psu.edu, kmacy@netapp.com, efeingold@mn.rr.com,
linux-kernel@vger.kernel.org
Subject: Re: Multithreaded core dumps
Date: Thu, 30 Aug 2001 02:33:12 -0700 (PDT) [thread overview]
Message-ID: <20010830.023312.58456523.davem@redhat.com> (raw)
In-Reply-To: <E15cNsX-0000m7-00@the-village.bc.nu>
In-Reply-To: <Pine.GSO.4.21.0108300457270.9879-100000@weyl.math.psu.edu> <E15cNsX-0000m7-00@the-village.bc.nu>
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
Date: Thu, 30 Aug 2001 10:12:49 +0100 (BST)
> ... and these dumps are not reliable. Living thread may modify the
> contents of dump as it's being written out. I.e. you are getting
> false alarms - inconsistent data that was never there.
That is mathematically insoluble. Think about an SMP system, you cannot stop
the other thread in instantaneously small time
If you mean "at the time the user process trapped", pretty much this
is true.
But it _IS_ possible to capture the other threads with an SMP cross
call at the time the bad condition leading to the dump is detected.
thread_dont_schedule(t);
smp_reschedule();
t->dump_core(t);
thread_re_schedule(t);
Later,
David S. Miller
davem@redhat.com
next prev parent reply other threads:[~2001-08-30 9:33 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-08-30 5:21 Multithreaded core dumps Elan Feingold
2001-08-30 5:50 ` Kip Macy
2001-08-30 8:24 ` Alan Cox
2001-08-30 9:03 ` Alexander Viro
2001-08-30 9:12 ` Alan Cox
2001-08-30 9:33 ` David S. Miller [this message]
2001-08-30 10:08 ` Alexander Viro
2001-08-30 8:16 ` Multithreaded core dumps (CLONE_THREAD and elf) Terje Eggestad
2001-08-30 9:19 ` Andreas Dilger
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