From: Alexander Potapenko <gli...@google.com> 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.
[a...@linux-foundation.org: cleanup: use WARN_ONCE return value] Link: http://lkml.kernel.org/r/1470063563-96266-1-git-send-email-gli...@google.com Fixes: 55834c59098d ("mm: kasan: initial memory quarantine implementation") Signed-off-by: Alexander Potapenko <gli...@google.com> Reported-by: Dmitry Vyukov <dvyu...@google.com> Cc: Andrey Ryabinin <aryabi...@virtuozzo.com> Signed-off-by: Andrew Morton <a...@linux-foundation.org> Signed-off-by: Linus Torvalds <torva...@linux-foundation.org> https://jira.sw.ru/browse/PSBM-69081 (cherry picked from commit c3cee372282cb6bcdf19ac1457581d5dd5ecb554) Signed-off-by: Andrey Ryabinin <aryabi...@virtuozzo.com> --- 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 7fd121d13b88..b6728a33a4ac 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; -- 2.13.5 _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel
