[PATCH][usercr]: Ghost tasks must be detached
Louis.Rilling at kerlabs.com
Thu Feb 10 02:23:12 PST 2011
On 09/02/11 11:02 -0800, Sukadev Bhattiprolu wrote:
> Louis Rilling [Louis.Rilling at kerlabs.com] wrote:
> | > | Are we still getting it with 2.6.37 ?
> | >
> | > I am not currently getting the crash on 2.6.37 - I thought it was due to
> | > the following commit which removed the check for task_detached() in
> | > do_wait_thread().
> | >
> | > commit 9cd80bbb07fcd6d4d037fad4297496d3b132ac6b
> | > Author: Oleg Nesterov <oleg at redhat.com>
> | > Date: Thu Dec 17 15:27:15 2009 -0800
> | I don't think that this introduced the bug. The bug triggers with EXIT_DEAD
> | tasks, for which wait() must ignore (see below). So, the bug looks still there
> | in 2.6.37.
> Sorry, I did not mean to imply that the above commit caused the crash
> you saw in Jun 2010.
> I can reproduce a crash with 2.6.32 - where if container-init terminates
> before a detached child, we get a crash when the detached child calls
> proc_flush_mnt(). I suspected it was because do_wait_thread() skipped
> over detached tasks (in 2.6.32).
> The same test case does not crash on 2.6.37 - which includes the above commit.
> The removes the check for detached tasks, my initial guess is that the above
> commit, may have contributed to _fixing_ the crash in 2.6.37.
Hm, I don't see how this commit changed things for detached tasks, unless ptrace
is involved. Detached tasks go atomically
from ->exit_state == 0 to ->exit_state == EXIT_DEAD in exit_notify(),
because tracehook_notify_death() returns DEATH_REAP for all not ptraced detached
What do you think has changed precisely?
Dr Louis Rilling Kerlabs
Skype: louis.rilling Batiment Germanium
Phone: (+33|0) 6 80 89 08 23 80 avenue des Buttes de Coesmes
http://www.kerlabs.com/ 35700 Rennes
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Size: 197 bytes
Desc: Digital signature
Url : http://lists.linux-foundation.org/pipermail/containers/attachments/20110210/d8e2dfc0/attachment-0001.pgp
More information about the Containers