diff mbox series

[5/6] mm, notifier: Catch sleeping/blocking for !blockable

Message ID 20181025143527.8575-6-daniel.vetter@ffwll.ch (mailing list archive)
State New, archived
Headers show
Series attempts at catching mmu_notifer deadlocks | expand

Commit Message

Daniel Vetter Oct. 25, 2018, 2:35 p.m. UTC 
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.

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
---
 mm/mmu_notifier.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c
index 744840e5636e..4d56e2645b6c 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,