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From: "Kawai, Hidehiro" <firstname.lastname@example.org> To: Markus Gutschke <email@example.com> Cc: Andrew Morton <firstname.lastname@example.org>, kernel list <email@example.com>, Pavel Machek <firstname.lastname@example.org>, Robin Holt <email@example.com>, firstname.lastname@example.org, Alan Cox <email@example.com>, Masami Hiramatsu <firstname.lastname@example.org>, sugita <email@example.com>, Satoshi OSHIMA <firstname.lastname@example.org>, "Hideo AOKI@redhat" <email@example.com> Subject: Re: [PATCH 0/4] coredump: core dump masking support v3 Date: Thu, 01 Mar 2007 21:35:20 +0900 [thread overview] Message-ID: <45E6C888.firstname.lastname@example.org> (raw) In-Reply-To: <45DFB1C7.email@example.com> Hi, Markus Gutschke wrote: > Kawai, Hidehiro wrote: > >> This patch series is version 3 of the core dump masking feature, >> which provides a per-process flag not to dump anonymous shared >> memory segments. > > I just wanted to remind you that you need to be careful about dumping > the [vdso] segment no matter whether you omit other segments. I didn't > actually try running your patches, and if the kernel doesn't actually > consider this segment anonymous and shared, things might already work > fine as is. Thank you for your advice and sorry for not replying soon. Fortunately, the latest kernel uses VM_ALWAYSDUMP flag to always dump the vdso segment. My patchset doesn't change this behavior. So we don't need to worry about the vdso segment. > As an alternative to your kernel patch, you could achieve the same goal > in user space, by linking my coredumper > http://code.google.com/p/google-coredumper/ into your binaries and > setting up appropriate signal handlers. An equivalent patch for > selectively omitting memory regions would be trivial to add. As far as I can see, google-coredumper has more flexibility. Can google-coredumper satisfy the following requirements easily? Requirements are: (1) a user can change the core dump settings _anytime_ - sometimes want to dump anonymous shared memory segments and sometimes don't want to dump them (2) a user can change the core dump settings of _any processes_ (although permission checks are performed) - in a huge application which forks many processes, a user hopes that some processes dump anonymous shared memory segments and some processes don't dump them And reliability of the core dump feature is also important. > While this > does give you more flexibility, it of course has the drawback of > requiring you to change your applications, so there still is some > benefit in a kernelspace solution. And all the software vendors don't necessarily apply google-coredumper. If the vendor doesn't apply it, the user will be bothered by huge core dumps or the buggy application which remains unfixed. So I believe that in kernel solution is still needed. Thanks, -- Hidehiro Kawai Hitachi, Ltd., Systems Development Laboratory
next prev parent reply other threads:[~2007-03-01 12:35 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 [this message] 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
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