Re: WARNING: suspicious RCU usage in modeset_lock

2020-12-22 Thread Boqun Feng
Hi Dmitry, On Fri, Dec 18, 2020 at 12:27:04PM +0100, Dmitry Vyukov wrote: > On Fri, Dec 18, 2020 at 2:30 AM Boqun Feng wrote: > > > > On Thu, Dec 17, 2020 at 07:21:18AM -0800, Paul E. McKenney wrote: > > > On Thu, Dec 17, 2020 at 11:03:20AM +0100, Daniel Vetter wrote: > > > > On Wed, Dec 16, 2020

Re: WARNING: suspicious RCU usage in modeset_lock

2020-12-20 Thread Tetsuo Handa
On Wed, Dec 16, 2020 at 5:16 PM Paul E. McKenney wrote: > In my experience, lockdep will indeed complain if an interrupt handler > returns while in an RCU read-side critical section. Can't we add lock status checks into the beginning and the end of interrupt handler functions (e.g. whether "stru

Re: WARNING: suspicious RCU usage in modeset_lock

2020-12-18 Thread Daniel Vetter
On Fri, Dec 18, 2020 at 5:10 PM Steven Rostedt wrote: > > On Thu, 17 Dec 2020 11:03:20 +0100 > Daniel Vetter wrote: > > > I think we're tripping over the might_sleep() all the mutexes have, > > and that's not as good as yours, but good enough to catch a missing > > rcu_read_unlock(). That's kinda

Re: WARNING: suspicious RCU usage in modeset_lock

2020-12-18 Thread Steven Rostedt
On Thu, 17 Dec 2020 11:03:20 +0100 Daniel Vetter wrote: > I think we're tripping over the might_sleep() all the mutexes have, > and that's not as good as yours, but good enough to catch a missing > rcu_read_unlock(). That's kinda why I'm baffled, since like almost > every 2nd function in the back

Re: WARNING: suspicious RCU usage in modeset_lock

2020-12-18 Thread Boqun Feng
On Thu, Dec 17, 2020 at 07:21:18AM -0800, Paul E. McKenney wrote: > On Thu, Dec 17, 2020 at 11:03:20AM +0100, Daniel Vetter wrote: > > On Wed, Dec 16, 2020 at 5:16 PM Paul E. McKenney wrote: > > > > > > On Wed, Dec 16, 2020 at 10:52:06AM +0100, Daniel Vetter wrote: > > > > On Wed, Dec 16, 2020 at

Re: WARNING: suspicious RCU usage in modeset_lock

2020-12-17 Thread Paul E. McKenney
On Thu, Dec 17, 2020 at 11:03:20AM +0100, Daniel Vetter wrote: > On Wed, Dec 16, 2020 at 5:16 PM Paul E. McKenney wrote: > > > > On Wed, Dec 16, 2020 at 10:52:06AM +0100, Daniel Vetter wrote: > > > On Wed, Dec 16, 2020 at 2:14 AM syzbot > > > wrote: > > > > > > > > Hello, > > > > > > > > syzbot f

Re: WARNING: suspicious RCU usage in modeset_lock

2020-12-17 Thread Daniel Vetter
On Wed, Dec 16, 2020 at 5:16 PM Paul E. McKenney wrote: > > On Wed, Dec 16, 2020 at 10:52:06AM +0100, Daniel Vetter wrote: > > On Wed, Dec 16, 2020 at 2:14 AM syzbot > > wrote: > > > > > > Hello, > > > > > > syzbot found the following issue on: > > > > > > HEAD commit:94801e5c Merge tag 'pinc

Re: WARNING: suspicious RCU usage in modeset_lock

2020-12-16 Thread Paul E. McKenney
On Wed, Dec 16, 2020 at 10:52:06AM +0100, Daniel Vetter wrote: > On Wed, Dec 16, 2020 at 2:14 AM syzbot > wrote: > > > > Hello, > > > > syzbot found the following issue on: > > > > HEAD commit:94801e5c Merge tag 'pinctrl-v5.10-3' of git://git.kernel.o.. > > git tree: upstream > > console

Re: WARNING: suspicious RCU usage in modeset_lock

2020-12-16 Thread Daniel Vetter
On Wed, Dec 16, 2020 at 2:14 AM syzbot wrote: > > Hello, > > syzbot found the following issue on: > > HEAD commit:94801e5c Merge tag 'pinctrl-v5.10-3' of git://git.kernel.o.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=130558c550 > kernel config:

WARNING: suspicious RCU usage in modeset_lock

2020-12-16 Thread syzbot
Hello, syzbot found the following issue on: HEAD commit:94801e5c Merge tag 'pinctrl-v5.10-3' of git://git.kernel.o.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=130558c550 kernel config: https://syzkaller.appspot.com/x/.config?x=ee8a1012a5314210 das