We need to make sure implementations don't cheat and don't have a possible schedule/blocking point deeply burried where review can't catch it.
I'm not sure whether this is the best way to make sure all the might_sleep() callsites trigger, and it's a bit ugly in the code flow. But it gets the job done.
Cc: Andrew Morton akpm@linux-foundation.org Cc: Michal Hocko mhocko@suse.com Cc: David Rientjes rientjes@google.com Cc: "Christian König" christian.koenig@amd.com Cc: Daniel Vetter daniel.vetter@ffwll.ch Cc: "Jérôme Glisse" jglisse@redhat.com Cc: linux-mm@kvack.org Signed-off-by: Daniel Vetter daniel.vetter@intel.com --- mm/mmu_notifier.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c index 59e102589a25..4d282cfb296e 100644 --- a/mm/mmu_notifier.c +++ b/mm/mmu_notifier.c @@ -185,7 +185,13 @@ int __mmu_notifier_invalidate_range_start(struct mm_struct *mm, id = srcu_read_lock(&srcu); hlist_for_each_entry_rcu(mn, &mm->mmu_notifier_mm->list, hlist) { if (mn->ops->invalidate_range_start) { - int _ret = mn->ops->invalidate_range_start(mn, mm, start, end, blockable); + int _ret; + + if (IS_ENABLED(CONFIG_DEBUG_ATOMIC_SLEEP) && !blockable) + preempt_disable(); + _ret = mn->ops->invalidate_range_start(mn, mm, start, end, blockable); + if (IS_ENABLED(CONFIG_DEBUG_ATOMIC_SLEEP) && !blockable) + preempt_enable(); if (_ret) { pr_info("%pS callback failed with %d in %sblockable context.\n", mn->ops->invalidate_range_start, _ret,