On Sat, 2013-07-27 at 21:34 +0800, Fengguang Wu wrote:
> On Sat, Jul 20, 2013 at 09:46:45AM -0700, Davidlohr Bueso wrote:
> > On Sun, 2013-07-21 at 00:02 +0800, Xiaotian Feng wrote:
> > > On Sat, Jul 20, 2013 at 9:13 PM, Fengguang Wu <fengguang...@intel.com>
> > > wrote:
> > > > Greetings,
> > > >
> > > > I got the below dmesg and the first bad commit is
> > > >
> > > > commit c5d0282a0405b0a81fa3390e4230e4cbb3ced7a2
> > > > Author: Davidlohr Bueso <davidlohr.bu...@hp.com>
> > > > Date: Fri Jul 19 09:56:58 2013 +1000
> > > >
> > > > ipc,shm: shorten critical region for shmat
> > > >
> > > > Similar to other system calls, acquire the kern_ipc_perm lock after
> > > > doing
> > > > the initial permission and security checks.
> > > >
> > > > Signed-off-by: Davidlohr Bueso <davidlohr.bu...@hp.com>
> > > > Tested-by: Sedat Dilek <sedat.di...@gmail.com>
> > > > Cc: Rik van Riel <r...@redhat.com>
> > > > Cc: Manfred Spraul <manf...@colorfullife.com>
> > > > Signed-off-by: Andrew Morton <a...@linux-foundation.org>
> > > >
> > > > [ 20.702156]
> > > > [ 20.702493] ================================================
> > > > [ 20.703511] [ BUG: lock held when returning to user space! ]
> > > > [ 20.704532] 3.11.0-rc1-next-20130719 #50 Not tainted
> > > > [ 20.705416] ------------------------------------------------
> > > > [ 20.706425] trinity-child0/174 is leaving the kernel with locks
> > > > still held!
> > > > [ 20.707638] 1 lock held by trinity-child0/174:
> > > > [ 20.708475] #0: (rcu_read_lock){.+.+..}, at: [<ffffffff814a8491>]
> > > > do_shmat+0xe1/0x500
> > > >
> > >
> > > ----
> > > ns = current->nsproxy->ipc_ns;
> > > - shp = shm_lock_check(ns, shmid);
> > > + rcu_read_lock();
> > > + shp = shm_obtain_object_check(ns, shmid);
> > > if (IS_ERR(shp)) {
> > > err = PTR_ERR(shp);
> > > goto out;
> > > ----
> > >
> > > If shm_obtain_object_check() failed, goto out will return with
> > > rcu_read_lock() held. I think following patch should cure this.
> >
> > Yep that should solve it, sorry about that. Sasha Levin sent out a fix
> > for it yesterday (offline).
>
> What's the patch's status? The bug is still there in linux-next 20130726.
Andrew, unless you have an objection (or have already done so), could
you pickup Sasha's fix?
Thanks,
Davidlohr
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