Messages in this thread | | | Date | Wed, 1 Jun 2011 12:32:58 +0900 | From | Minchan Kim <> | Subject | Re: [PATCH v2 0/5] Fix oom killer doesn't work at all if system have > gigabytes memory (aka CAI founded issue) |
| |
Hi KOSAKI,
On Tue, May 31, 2011 at 07:01:08PM +0900, KOSAKI Motohiro wrote: > (2011/05/31 17:11), KOSAKI Motohiro wrote: > >>> Then, I believe your distro applying distro specific patch to ssh. > >>> Which distro are you using now? > >> It is a Fedora-like distro. > > So, Does this makes sense? > > > > From e47fedaa546499fa3d4196753194db0609cfa2e5 Mon Sep 17 00:00:00 2001 > From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> > Date: Tue, 31 May 2011 18:28:30 +0900 > Subject: [PATCH] oom: use euid instead of CAP_SYS_ADMIN for protection root process > > Recently, many userland daemon prefer to use libcap-ng and drop > all privilege just after startup. Because of (1) Almost privilege > are necessary only when special file open, and aren't necessary > read and write. (2) In general, privilege dropping brings better > protection from exploit when bugs are found in the daemon. > > But, it makes suboptimal oom-killer behavior. CAI Qian reported > oom killer killed some important daemon at first on his fedora > like distro. Because they've lost CAP_SYS_ADMIN. > > Of course, we recommend to drop privileges as far as possible > instead of keeping them. Thus, oom killer don't have to check > any capability. It implicitly suggest wrong programming style. > > This patch change root process check way from CAP_SYS_ADMIN to > just euid==0.
I like this but I have some comments. Firstly, it's not dependent with your series so I think this could be merged firstly. Before that, I would like to make clear my concern. As I look below comment, 3% bonus is dependent with __vm_enough_memory's logic? If it isn't, we can remove the comment. It would be another patch. If is is, could we change __vm_enough_memory for euid instead of cap?
* Root processes get 3% bonus, just like the __vm_enough_memory() * implementation used by LSMs.
-- Kind regards Minchan Kim
| |