diff mbox series

[RFC,v2,6/6] mm: Add heap quarantine verbose debugging (not for merge)

Message ID 20200929183513.380760-7-alex.popov@linux.com
State New, archived
Headers show
Series Break heap spraying needed for exploiting use-after-free | expand

Commit Message

Alexander Popov Sept. 29, 2020, 6:35 p.m. UTC
Add verbose debugging for deeper understanding of the heap quarantine
inner workings (this patch is not for merge).

Signed-off-by: Alexander Popov <alex.popov@linux.com>
---
 mm/kasan/quarantine.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)
diff mbox series

Patch

diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c
index 4ce100605086..98cd6e963755 100644
--- a/mm/kasan/quarantine.c
+++ b/mm/kasan/quarantine.c
@@ -203,6 +203,12 @@  void quarantine_put(struct kasan_free_meta *info, struct kmem_cache *cache)
 		qlist_move_all(q, &temp);
 
 		raw_spin_lock(&quarantine_lock);
+
+		pr_info("quarantine: PUT %zu to tail batch %d, whole sz %zu, batch sz %lu\n",
+				temp.bytes, quarantine_tail,
+				READ_ONCE(quarantine_size),
+				READ_ONCE(quarantine_batch_size));
+
 		WRITE_ONCE(quarantine_size, quarantine_size + temp.bytes);
 		qlist_move_all(&temp, &global_quarantine[quarantine_tail]);
 		if (global_quarantine[quarantine_tail].bytes >=
@@ -313,7 +319,22 @@  void quarantine_reduce(void)
 			quarantine_head = get_random_int() % QUARANTINE_BATCHES;
 		} while (quarantine_head == quarantine_tail);
 		qlist_move_random(&global_quarantine[quarantine_head], &to_free);
+		pr_info("quarantine: whole sz exceed max by %lu, REDUCE head batch %d by %zu, leave %zu\n",
+				quarantine_size - quarantine_max_size,
+				quarantine_head, to_free.bytes,
+				global_quarantine[quarantine_head].bytes);
 		WRITE_ONCE(quarantine_size, quarantine_size - to_free.bytes);
+
+		if (quarantine_head == 0) {
+			unsigned long i;
+
+			pr_info("quarantine: data level in batches:");
+			for (i = 0; i < QUARANTINE_BATCHES; i++) {
+				pr_info("  %lu - %lu%%\n",
+					i, global_quarantine[i].bytes *
+						100 / quarantine_batch_size);
+			}
+		}
 	}
 #endif