Re: INFO: rcu detected stall in smp_call_function

2020-09-06 Thread syzbot
syzbot has found a reproducer for the following issue on: HEAD commit:dd9fb9bb Merge tags 'auxdisplay-for-linus-v5.9-rc4', 'clan.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=124893e190 kernel config: https://syzkaller.appspot.com/x/.config?x=bd46548

Re: INFO: rcu detected stall in smp_call_function

2020-08-26 Thread Paul E. McKenney
On Wed, Aug 26, 2020 at 07:07:33AM -0700, Paul E. McKenney wrote: > On Wed, Aug 26, 2020 at 11:51:44AM +0200, pet...@infradead.org wrote: > > On Tue, Aug 25, 2020 at 08:48:41AM -0700, Paul E. McKenney wrote: > > > > > > Paul, I wanted to use this function, but found it has very weird > > > > seman

Re: INFO: rcu detected stall in smp_call_function

2020-08-26 Thread Paul E. McKenney
On Wed, Aug 26, 2020 at 11:51:44AM +0200, pet...@infradead.org wrote: > On Tue, Aug 25, 2020 at 08:48:41AM -0700, Paul E. McKenney wrote: > > > > Paul, I wanted to use this function, but found it has very weird > > > semantics. > > > > > > Why do you need it to (remotely) call @func when p is cur

Re: INFO: rcu detected stall in smp_call_function

2020-08-26 Thread peterz
On Tue, Aug 25, 2020 at 08:48:41AM -0700, Paul E. McKenney wrote: > > Paul, I wanted to use this function, but found it has very weird > > semantics. > > > > Why do you need it to (remotely) call @func when p is current? The user > > in rcu_print_task_stall() explicitly bails in this case, and th

Re: INFO: rcu detected stall in smp_call_function

2020-08-25 Thread Paul E. McKenney
On Tue, Aug 25, 2020 at 03:24:11PM +0200, pet...@infradead.org wrote: > > +Cc Paul, who was weirdly forgotten last time > > And one additional question below, which made me remember this thing. > > On Wed, Jul 29, 2020 at 02:58:11PM +0200, pet...@infradead.org wrote: > > > > rcu: INFO: rcu_pree

Re: INFO: rcu detected stall in smp_call_function

2020-08-25 Thread peterz
+Cc Paul, who was weirdly forgotten last time And one additional question below, which made me remember this thing. On Wed, Jul 29, 2020 at 02:58:11PM +0200, pet...@infradead.org wrote: > > rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: > > rcu:Tasks blocked on level-0 rcu_node

Re: INFO: rcu detected stall in smp_call_function

2020-07-29 Thread peterz
On Wed, Jul 29, 2020 at 01:44:15AM -0700, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit:6ba1b005 Merge tag 'asm-generic-fixes-5.8' of git://git.ke.. Bit useless, having git://git.ke... there, that doesn't really narrow things down. > git tree: upstrea

INFO: rcu detected stall in smp_call_function

2020-07-29 Thread syzbot
Hello, syzbot found the following issue on: HEAD commit:6ba1b005 Merge tag 'asm-generic-fixes-5.8' of git://git.ke.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=14da552290 kernel config: https://syzkaller.appspot.com/x/.config?x=812bbfcb6ae2cd60 das