The commit is pushed to "branch-rh7-3.10.0-693.1.1.vz7.37.x-ovz" and will
appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-693.1.1.vz7.37.4
------>
commit adcb15484ab1a2cf8e49fcf778bf42af2c423687
Author: Alexander Potapenko <[email protected]>
Date: Fri Sep 15 17:27:28 2017 +0300
kasan: avoid overflowing quarantine size on low memory systems
If the total amount of memory assigned to quarantine is less than the
amount of memory assigned to per-cpu quarantines, |new_quarantine_size|
may overflow. Instead, set it to zero.
[[email protected]: cleanup: use WARN_ONCE return value]
Link:
http://lkml.kernel.org/r/[email protected]
Fixes: 55834c59098d ("mm: kasan: initial memory quarantine implementation")
Signed-off-by: Alexander Potapenko <[email protected]>
Reported-by: Dmitry Vyukov <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
https://jira.sw.ru/browse/PSBM-69081
(cherry picked from commit c3cee372282cb6bcdf19ac1457581d5dd5ecb554)
Signed-off-by: Andrey Ryabinin <[email protected]>
---
mm/kasan/quarantine.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c
index 7fd121d..b6728a3 100644
--- a/mm/kasan/quarantine.c
+++ b/mm/kasan/quarantine.c
@@ -198,7 +198,7 @@ void quarantine_put(struct kasan_free_meta *info, struct
kmem_cache *cache)
void quarantine_reduce(void)
{
- size_t new_quarantine_size;
+ size_t new_quarantine_size, percpu_quarantines;
unsigned long flags;
struct qlist_head to_free = QLIST_INIT;
size_t size_to_free = 0;
@@ -216,7 +216,12 @@ void quarantine_reduce(void)
*/
new_quarantine_size = (READ_ONCE(totalram_pages) << PAGE_SHIFT) /
QUARANTINE_FRACTION;
- new_quarantine_size -= QUARANTINE_PERCPU_SIZE * num_online_cpus();
+ percpu_quarantines = QUARANTINE_PERCPU_SIZE * num_online_cpus();
+ if (WARN_ONCE(new_quarantine_size < percpu_quarantines,
+ "Too little memory, disabling global KASAN quarantine.\n"))
+ new_quarantine_size = 0;
+ else
+ new_quarantine_size -= percpu_quarantines;
WRITE_ONCE(quarantine_size, new_quarantine_size);
last = global_quarantine.head;
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