On Thu, Mar 27, 2014 at 10:23:33AM +0530, Preeti U Murthy wrote: > Hi, > > I had sent out a request for the backport on 2014-03-17 16:17:32 GMT > titled "sched/autogroup: Fix race with task_groups list". I did not > however hear back about the status of the review of this backport. > Can you please let me know about the same? The below patch is known > to have fixed several boot time kernel oops on some of our local > machines and would be good to have it in the 3.10 stable kernel. I have no record of your email, sorry. > > Thanks > > Regards > Preeti U Murthy > > > From: Gerald Schaefer <gerald.schaefer <at> de.ibm.com> > > commit 41261b6a832ea0e788627f6a8707854423f9ff49 upstream > > In autogroup_create(), a tg is allocated and added to the task_groups > list. If CONFIG_RT_GROUP_SCHED is set, this tg is then modified while on > the list, without locking. This can race with someone walking the list, > like __enable_runtime() during CPU unplug, and result in a use-after-free > bug. > > To fix this, move sched_online_group(), which adds the tg to the list, > to the end of the autogroup_create() function after the modification. > > Please backport this fix to stable/3.10.y. There were many reports > of kernel oops on 3.10 due to the absence of this fix. > > Signed-off-by: Gerald Schaefer <gerald.schaefer <at> de.ibm.com> > Signed-off-by: Peter Zijlstra <peterz <at> infradead.org> > Link: http://lkml.kernel.org/r/1369411669-46971-2-git-send-email-gerald.schaefer <at> de.ibm.com > Signed-off-by: Ingo Molnar <mingo <at> kernel.org> > Signed-off-by: Preeti U Murthy <preeti <at> linux.vnet.ibm.com> > --- > > kernel/sched/auto_group.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/kernel/sched/auto_group.c b/kernel/sched/auto_group.c > index 64de5f8..4a07353 100644 > --- a/kernel/sched/auto_group.c > +++ b/kernel/sched/auto_group.c > <at> <at> -77,8 +77,6 <at> <at> static inline struct autogroup *autogroup_create(void) > if (IS_ERR(tg)) > goto out_free; > > - sched_online_group(tg, &root_task_group); > - > kref_init(&ag->kref); > init_rwsem(&ag->lock); > ag->id = atomic_inc_return(&autogroup_seq_nr); > <at> <at> -98,6 +96,7 <at> <at> static inline struct autogroup *autogroup_create(void) > #endif > tg->autogroup = ag; > > + sched_online_group(tg, &root_task_group); > return ag; > > out_free: That is not in any form that could be applied :( Please fix your email client and try again. -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html