From: Daniel Jacobowitz <drow@false.org>
To: Neil Horman <nhorman@tuxdriver.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, bugme-daemon@bugzilla.kernel.org,
Roland McGrath <roland@redhat.com>,
Oleg Nesterov <oleg@tv-sign.ru>,
Alan Cox <alan@lxorguk.ukuu.org.uk>
Subject: Re: [Bugme-new] [Bug 11110] New: Core dumps do not include writable unmodified MAP_PRIVATE maps
Date: Thu, 17 Jul 2008 17:20:23 -0400 [thread overview]
Message-ID: <20080717212023.GA20584@caradoc.them.org> (raw)
In-Reply-To: <20080717203930.GA24299@hmsendeavour.rdu.redhat.com>
On Thu, Jul 17, 2008 at 04:39:30PM -0400, Neil Horman wrote:
> I'm not 100% sure, and I can see why the kernel might skip over untouched pages,
> but that seems like a bug to me. The memory is mapped, it should be readable by
> gdb after a core dump, and since its a mapped file, it can't be assumed to be
> zero, like heap memory that hasn't been faulted in yet.
I'm guessing this is an attempt not to dump shared library text
segments. We can't do it solely based on permissions; if I remember
right there's a readonly page in the application or ld.so associated
with the shared library list that is mprotected to read-only after
initialization (-z relro).
In April 2006 Dave M suggested only skipping if VM_EXEC. This will
dump some text segment bits (e.g. anything that had a software
breakpoint inserted), but not most; writable data is usually written
to (at least mostly).
--
Daniel Jacobowitz
CodeSourcery
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next prev parent reply other threads:[~2008-07-17 21:20 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <bug-11110-10286@http.bugzilla.kernel.org/>
2008-07-17 20:23 ` [Bugme-new] [Bug 11110] New: Core dumps do not include writable unmodified MAP_PRIVATE maps Andrew Morton
2008-07-17 20:39 ` Neil Horman
2008-07-17 21:20 ` Daniel Jacobowitz [this message]
2008-07-17 22:13 ` Roland McGrath
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