[PATCH net-next 05/12] ptr_ring: disallow lockless __ptr_ring_full
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: 2018-01-25 23:38:48
Also in:
lkml
Subsystem:
the rest · Maintainer:
Linus Torvalds
Similar to bcecb4bbf88a ("net: ptr_ring: otherwise safe empty checks can
overrun array bounds") a lockless use of __ptr_ring_full might
cause an out of bounds access.
We can fix this, but it's easier to just disallow lockless
__ptr_ring_full for now.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
include/linux/ptr_ring.h | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/include/linux/ptr_ring.h b/include/linux/ptr_ring.h
index 9a72d8f..f175846 100644
--- a/include/linux/ptr_ring.h
+++ b/include/linux/ptr_ring.h@@ -45,9 +45,10 @@ struct ptr_ring { }; /* Note: callers invoking this in a loop must use a compiler barrier, - * for example cpu_relax(). If ring is ever resized, callers must hold - * producer_lock - see e.g. ptr_ring_full. Otherwise, if callers don't hold - * producer_lock, the next call to __ptr_ring_produce may fail. + * for example cpu_relax(). + * + * NB: this is unlike __ptr_ring_empty in that callers must hold producer_lock: + * see e.g. ptr_ring_full. */ static inline bool __ptr_ring_full(struct ptr_ring *r) {
--
MST