Messages in this thread | | | Date | Tue, 5 Sep 2006 10:41:56 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | Re: [RFC][PATCH] ps command race fix take 4 [1/4] callback subroutine |
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On Mon, 04 Sep 2006 16:48:43 -0600 ebiederm@xmission.com (Eric W. Biederman) wrote:
> KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> writes: > > > Updated some dirty codes. maybe easier to read than previous one. > > > > This ps command fix (proc_pid_readdir() fix) fixes the problem by > > > > - attach a callback for updating pointer from file descriptor to a task invoked > > at release_task() > > - no additional global lock is required. > > - walk through all and only task structs which is thread group leader. > > > > *Bad* point is adding additonal (small) lock and callback in exit path. > With an unbounded callback chain length influenced by user space. > yes. 1000 ps process will add 1000 chains. 1000 callbacks are called if a task is removed while 1000 ps task points to it.
-Kame
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