diff options
| author | Alexander Potapenko <glider@google.com> | 2016-08-02 14:02:58 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-09-30 10:12:48 +0200 |
| commit | cf48c9242444b9d542e2fe7e6ca01b8da00a1bc3 (patch) | |
| tree | d43fc539d00f5a0e3a44d57b3926c4e957d70367 | |
| parent | 6eeab2dc304a732722f77061ae364d102732943d (diff) | |
| download | lwn-cf48c9242444b9d542e2fe7e6ca01b8da00a1bc3.tar.gz lwn-cf48c9242444b9d542e2fe7e6ca01b8da00a1bc3.zip | |
kasan: avoid overflowing quarantine size on low memory systems
commit c3cee372282cb6bcdf19ac1457581d5dd5ecb554 upstream.
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.
[akpm@linux-foundation.org: cleanup: use WARN_ONCE return value]
Link: http://lkml.kernel.org/r/1470063563-96266-1-git-send-email-glider@google.com
Fixes: 55834c59098d ("mm: kasan: initial memory quarantine implementation")
Signed-off-by: Alexander Potapenko <glider@google.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | mm/kasan/quarantine.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c index 65793f150d1f..a04887c624ed 100644 --- a/mm/kasan/quarantine.c +++ b/mm/kasan/quarantine.c @@ -196,7 +196,7 @@ 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; @@ -214,7 +214,12 @@ 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; |