Re: srcu: BUG in __synchronize_srcu

2017-03-27 Thread Dmitry Vyukov
On Mon, Mar 27, 2017 at 4:16 PM, Paul E. McKenney wrote: > On Mon, Mar 27, 2017 at 02:36:35PM +0200, Dmitry Vyukov wrote: >> On Tue, Mar 14, 2017 at 5:21 PM, Paul E. McKenney >> wrote: >> > On Tue, Mar 14, 2017 at 12:47:02AM -0700, Lance Roy wrote: >> >> I am not sure how the rcu_scheduler_active

Re: srcu: BUG in __synchronize_srcu

2017-03-27 Thread Paul E. McKenney
On Mon, Mar 27, 2017 at 02:36:35PM +0200, Dmitry Vyukov wrote: > On Tue, Mar 14, 2017 at 5:21 PM, Paul E. McKenney > wrote: > > On Tue, Mar 14, 2017 at 12:47:02AM -0700, Lance Roy wrote: > >> I am not sure how the rcu_scheduler_active changes in __synchronize_srcu > >> work, > >> but there seem t

Re: srcu: BUG in __synchronize_srcu

2017-03-27 Thread Dmitry Vyukov
On Tue, Mar 14, 2017 at 5:21 PM, Paul E. McKenney wrote: > On Tue, Mar 14, 2017 at 12:47:02AM -0700, Lance Roy wrote: >> I am not sure how the rcu_scheduler_active changes in __synchronize_srcu >> work, >> but there seem to be a few problems in them. First, >> "if (done && likely(!driving))" on l

Re: srcu: BUG in __synchronize_srcu

2017-03-14 Thread Paul E. McKenney
On Tue, Mar 14, 2017 at 12:47:02AM -0700, Lance Roy wrote: > I am not sure how the rcu_scheduler_active changes in __synchronize_srcu work, > but there seem to be a few problems in them. First, > "if (done && likely(!driving))" on line 453 doesn't appear to ever happen, > as driving doesn't get set

Re: srcu: BUG in __synchronize_srcu

2017-03-14 Thread Lance Roy
I am not sure how the rcu_scheduler_active changes in __synchronize_srcu work, but there seem to be a few problems in them. First, "if (done && likely(!driving))" on line 453 doesn't appear to ever happen, as driving doesn't get set to false when srcu_reschedule is called. This seems like it could

Re: srcu: BUG in __synchronize_srcu

2017-03-11 Thread Paul E. McKenney
On Sat, Mar 11, 2017 at 02:25:14PM +, Mathieu Desnoyers wrote: > - On Mar 10, 2017, at 5:26 PM, Paul E. McKenney > paul...@linux.vnet.ibm.com wrote: > > > On Fri, Mar 10, 2017 at 08:29:55PM +0100, Andrey Konovalov wrote: > >> On Fri, Mar 10, 2017 at 8:28 PM, Andrey Konovalov > >> wrote:

Re: srcu: BUG in __synchronize_srcu

2017-03-11 Thread Mathieu Desnoyers
- On Mar 10, 2017, at 5:26 PM, Paul E. McKenney paul...@linux.vnet.ibm.com wrote: > On Fri, Mar 10, 2017 at 08:29:55PM +0100, Andrey Konovalov wrote: >> On Fri, Mar 10, 2017 at 8:28 PM, Andrey Konovalov >> wrote: >> > Hi, >> > >> > I've got the following error report while fuzzing the kerne

Re: srcu: BUG in __synchronize_srcu

2017-03-10 Thread Paul E. McKenney
On Fri, Mar 10, 2017 at 08:29:55PM +0100, Andrey Konovalov wrote: > On Fri, Mar 10, 2017 at 8:28 PM, Andrey Konovalov > wrote: > > Hi, > > > > I've got the following error report while fuzzing the kernel with > > syzkaller on an arm64 board. > > This also happened on x86 a few times during fuzzi

Re: srcu: BUG in __synchronize_srcu

2017-03-10 Thread Dmitry Vyukov
On Fri, Mar 10, 2017 at 8:29 PM, 'Andrey Konovalov' via syzkaller wrote: > On Fri, Mar 10, 2017 at 8:28 PM, Andrey Konovalov > wrote: >> Hi, >> >> I've got the following error report while fuzzing the kernel with >> syzkaller on an arm64 board. > > This also happened on x86 a few times during fu

Re: srcu: BUG in __synchronize_srcu

2017-03-10 Thread Andrey Konovalov
On Fri, Mar 10, 2017 at 8:28 PM, Andrey Konovalov wrote: > Hi, > > I've got the following error report while fuzzing the kernel with > syzkaller on an arm64 board. This also happened on x86 a few times during fuzzing, however it wasn't reproducible. > > On linux-next commit 56b8bad5e066c23e8fa27