Re: [patch 1/3] ipc/sem: fix -rt livelock

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Fri, 2013-10-04 at 13:28 +0200, Sebastian Andrzej Siewior wrote: 
> On 10/04/2013 01:16 PM, Mike Galbraith wrote:
> > Manfred's race fix also kills loop, and thereby the -rt livelock, so the
> > only question is does -rt want to use his completion wakeup scheme, and
> > does it want to do something about spin_unlock_wait() unconditionally
> > grabbing/releasing every lock in the array.
> 
> So his patches went into v3.11 or so right? So all -RT released post
> this point will have it fixed right?

Most fixes have gone into master.  There's still at least one in the
pipe, ipc/sem.c: synchronize semop and semctl with IPC_RMID, and I
_think_ there's still one open issue.

<quoting Manfred>
And now new:
1) ipc/namespace.c:
     free_ipcs() still assumes the "old style" free calls:
     rcu_lock and ipc_lock dropped within the callback.

     freeary() was converted - but free_ipcs was not updated.

     Thus:
     Closing a namespace with sem arrays and threads that are waiting
on 
the array with semtimedop() and bad timing can deadlock the semtimedop 
thread.
     (i.e.: spin_lock() waiting forever).
</quoting Manfred>

3.10,11-stable need the lot.

-Mike

--
To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [RT Stable]     [Kernel Newbies]     [IDE]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux ATA RAID]     [Samba]     [Video 4 Linux]     [Device Mapper]

  Powered by Linux