From: Jason Wang <jasowang@redhat.com>
To: mst@redhat.com
Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
Jason Wang <jasowang@redhat.com>
Subject: [PATCH net V2 2/2] ptr_ring: fail on large queue size (>64K)
Date: Thu, 8 Feb 2018 11:21:41 +0800 [thread overview]
Message-ID: <1518060101-19071-2-git-send-email-jasowang@redhat.com> (raw)
In-Reply-To: <1518060101-19071-1-git-send-email-jasowang@redhat.com>
We need limit the maximum size of queue, otherwise it may cause
several side effects e.g slab will warn when the size exceeds
KMALLOC_MAX_SIZE. Using KMALLOC_MAX_SIZE still looks too so this patch
tries to limit it to 64K. This value could be revisited if we found a
real case that needs more.
Reported-by: syzbot+e4d4f9ddd4295539735d@syzkaller.appspotmail.com
Fixes: 2e0ab8ca83c12 ("ptr_ring: array based FIFO for pointers")
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
include/linux/ptr_ring.h | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/include/linux/ptr_ring.h b/include/linux/ptr_ring.h
index 9c3b748..2520daa 100644
--- a/include/linux/ptr_ring.h
+++ b/include/linux/ptr_ring.h
@@ -44,6 +44,8 @@ struct ptr_ring {
void **queue;
};
+#define PTR_RING_MAX_ALLOC 65536
+
/* Note: callers invoking this in a loop must use a compiler barrier,
* for example cpu_relax().
*
@@ -466,6 +468,8 @@ static inline int ptr_ring_consume_batched_bh(struct ptr_ring *r,
static inline void **__ptr_ring_init_queue_alloc(unsigned int size, gfp_t gfp)
{
+ if (size > PTR_RING_MAX_ALLOC)
+ return NULL;
return kvmalloc_array(size, sizeof(void *), gfp | __GFP_ZERO);
}
--
2.7.4
next prev parent reply other threads:[~2018-02-08 3:21 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-08 3:21 [PATCH net V2 1/2] ptr_ring: try vmalloc() when kmalloc() fails Jason Wang
2018-02-08 3:21 ` Jason Wang [this message]
2018-02-08 3:26 ` Jason Wang
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