From: "Kawai, Hidehiro" <hidehiro.kawai.ez@hitachi.com>
To: David Howells <dhowells@redhat.com>
Cc: 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>,
"Hideo AOKI@redhat" <haoki@redhat.com>
Subject: Re: [PATCH 3/4] coredump: ELF-FDPIC: enable to omit anonymous shared memory
Date: Tue, 20 Feb 2007 18:45:15 +0900 [thread overview]
Message-ID: <45DAC32B.4030603@hitachi.com> (raw)
In-Reply-To: <20368.1171638335@redhat.com>
Hi,
Thank you for your comments.
David Howells wrote:
>> static int elf_fdpic_dump_segments(struct file *file, struct mm_struct *mm,
>>- size_t *size, unsigned long *limit)
>>+ size_t *size, unsigned long *limit,
>>+ unsigned int omit_anon_shared)
>
> Why are you passing it as an extra argument when you could just use
> mm->coredump_omit_anon_shared here:
>
>>+ if (!maydump(vma, omit_anon_shared))
> I wouldn't worry, were I you, about the setting changing whilst it's being
> used. If you are worried about that, you can probably do some locking against
> that.
Core dumping is separated two phases, one is the phase of writing
headers, the other is the phase of writing memory segments. If the
coredump_omit_anon_shared setting is changed between these two phases,
a corrupted core file will be generated because the offsets written
in headers don't match their bodies. So we need to use the same
setting in both phases.
I think that locking makes codes complex and generates overhead.
So I wouldn't like to use lock as far as possible. I think passing
the flag as an extra argument is the simplest implementation to
avoid the core file corruption.
Thanks,
--
Hidehiro Kawai
Hitachi, Ltd., Systems Development Laboratory
next prev parent reply other threads:[~2007-02-20 9:45 UTC|newest]
Thread overview: 44+ 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 ` Kawai, Hidehiro [this message]
2007-02-20 10:58 ` [PATCH 3/4] coredump: ELF-FDPIC: enable to omit anonymous shared memory 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
2007-02-26 12:01 ` Pavel Machek
2007-02-26 12:42 ` David Howells
2007-03-02 4:41 [PATCH 0/4] coredump: core dump masking support v4 Kawai, Hidehiro
2007-03-02 4:50 ` [PATCH 3/4] coredump: ELF-FDPIC: enable to omit anonymous shared memory Kawai, Hidehiro
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