Re: BUG_ON(!newowner) in fixup_pi_state_owner()

2020-11-04 Thread Mike Galbraith
On Wed, 2020-11-04 at 14:26 +0100, Thomas Gleixner wrote: > > I'll post that with a proper comment and changelog. Mike, can I add your > Signed-off-by to the thing? I suppose. -Mike

Re: BUG_ON(!newowner) in fixup_pi_state_owner()

2020-11-04 Thread Thomas Gleixner
On Wed, Nov 04 2020 at 12:17, Thomas Gleixner wrote: > On Wed, Nov 04 2020 at 11:24, Thomas Gleixner wrote: >> On Wed, Nov 04 2020 at 08:42, Mike Galbraith wrote: >>> On Wed, 2020-11-04 at 01:56 +0100, Mike Galbraith wrote: >>> --- a/kernel/futex.c >>> +++ b/kernel/futex.c >>> @@ -2383,7 +2383,18 @

Re: BUG_ON(!newowner) in fixup_pi_state_owner()

2020-11-04 Thread Thomas Gleixner
On Wed, Nov 04 2020 at 11:24, Thomas Gleixner wrote: > On Wed, Nov 04 2020 at 08:42, Mike Galbraith wrote: >> On Wed, 2020-11-04 at 01:56 +0100, Mike Galbraith wrote: >> --- a/kernel/futex.c >> +++ b/kernel/futex.c >> @@ -2383,7 +2383,18 @@ static int fixup_pi_state_owner(u32 __us >>

Re: BUG_ON(!newowner) in fixup_pi_state_owner()

2020-11-04 Thread Thomas Gleixner
On Wed, Nov 04 2020 at 08:42, Mike Galbraith wrote: > On Wed, 2020-11-04 at 01:56 +0100, Mike Galbraith wrote: > --- a/kernel/futex.c > +++ b/kernel/futex.c > @@ -2383,7 +2383,18 @@ static int fixup_pi_state_owner(u32 __us >* Since we just failed the trylock; there must be an owner.

Re: BUG_ON(!newowner) in fixup_pi_state_owner()

2020-11-04 Thread Thomas Gleixner
On Tue, Nov 03 2020 at 17:31, Gratian Crisan wrote: > I apologize for waking up the futex demons (and replying to my own > email), but ... I was staring at it already but couldn't wrap my head around it. > Gratian Crisan writes: > I was able to reproduce the BUG_ON(!newowner) in fixup_pi_state_ow

Re: BUG_ON(!newowner) in fixup_pi_state_owner()

2020-11-03 Thread Mike Galbraith
On Wed, 2020-11-04 at 01:56 +0100, Mike Galbraith wrote: > On Tue, 2020-11-03 at 17:31 -0600, Gratian Crisan wrote: > > Hi all, > > > > I apologize for waking up the futex demons (and replying to my own > > email), but ... > > > > Gratian Crisan writes: > > > > > > Brandon and I have been debugging

Re: BUG_ON(!newowner) in fixup_pi_state_owner()

2020-11-03 Thread Mike Galbraith
On Tue, 2020-11-03 at 17:31 -0600, Gratian Crisan wrote: > Hi all, > > I apologize for waking up the futex demons (and replying to my own > email), but ... > > Gratian Crisan writes: > > > > Brandon and I have been debugging a nasty race that leads to > > BUG_ON(!newowner) in fixup_pi_state_owner()

Re: BUG_ON(!newowner) in fixup_pi_state_owner()

2020-11-03 Thread Gratian Crisan
Hi all, I apologize for waking up the futex demons (and replying to my own email), but ... Gratian Crisan writes: > > Brandon and I have been debugging a nasty race that leads to > BUG_ON(!newowner) in fixup_pi_state_owner() in futex.c. So far > we've only been able to reproduce the issue on 4.9.