On Wed, Jul 15, 2020 at 07:13:33PM -0400, Joel Fernandes wrote: > On Wed, Jul 15, 2020 at 2:56 PM Sebastian Andrzej Siewior > <bigeasy@xxxxxxxxxxxxx> wrote: > > > > On 2020-07-15 20:35:37 [+0200], Uladzislau Rezki (Sony) wrote: > > > @@ -3306,6 +3307,9 @@ kvfree_call_rcu_add_ptr_to_bulk(struct kfree_rcu_cpu *krcp, void *ptr) > > > if (IS_ENABLED(CONFIG_PREEMPT_RT)) > > > return false; > > > > > > + preempt_disable(); > > > + krc_this_cpu_unlock(*krcp, *flags); > > > > Now you enter memory allocator with disabled preemption. This isn't any > > better but we don't have a warning for this yet. > > What happened to the part where I asked for a spinlock_t? > > Ulad, > Wouldn't the replacing of preempt_disable() with migrate_disable() > above resolve Sebastian's issue? > This for regular kernel only. That means that migrate_disable() is equal to preempt_disable(). So, no difference. > > Or which scenario breaks? > Proposed patch fixes Sebastian's finding about CONFIG_PROVE_RAW_LOCK_NESTING kernel option, that checks nesting rules and forbids raw_spinlock versus spinlock mixing. Sebastian, could you please confirm that if that patch that is in question fixes it? It would be appreciated! -- Vlad Rezki
