From: Dan Carpenter <dan.carpenter@oracle.com>
To: rajur@chelsio.com
Cc: linux-rdma@vger.kernel.org
Subject: [bug report] RDMA/iw_cxgb4: Avoid touch after free error in ARP failure handlers
Date: Fri, 25 Oct 2019 13:41:11 +0300 [thread overview]
Message-ID: <20191025104111.GA12120@mwanda> (raw)
Hello Raju Rangoju,
The patch 1dad0ebeea1c: "RDMA/iw_cxgb4: Avoid touch after free error
in ARP failure handlers" from May 15, 2017, leads to the following
static checker warning:
drivers/infiniband/hw/cxgb4/cm.c:4310 process_work()
warn: 'skb' was already freed.
drivers/infiniband/hw/cxgb4/cm.c
4289 static void process_work(struct work_struct *work)
4290 {
4291 struct sk_buff *skb = NULL;
4292 struct c4iw_dev *dev;
4293 struct cpl_act_establish *rpl;
4294 unsigned int opcode;
4295 int ret;
4296
4297 process_timedout_eps();
4298 while ((skb = skb_dequeue(&rxq))) {
4299 rpl = cplhdr(skb);
4300 dev = *((struct c4iw_dev **) (skb->cb + sizeof(void *)));
4301 opcode = rpl->ot.opcode;
4302
4303 if (opcode >= ARRAY_SIZE(work_handlers) ||
4304 !work_handlers[opcode]) {
4305 pr_err("No handler for opcode 0x%x.\n", opcode);
4306 kfree_skb(skb);
4307 } else {
4308 ret = work_handlers[opcode](dev, skb);
4309 if (!ret)
4310 kfree_skb(skb);
I'm not sure why this warning didn't show up before... :(
We added some kfree_skb() calls to _put_ep_safe() and _put_pass_ep_safe().
The thing about kfree_skb() is that it's refcounted so it might not
free anything so this could be a false positive. I've looked at the
code and it looks like it could be a bug?
4311 }
4312 process_timedout_eps();
4313 }
4314 }
regards,
dan carpenter
next reply other threads:[~2019-10-25 10:41 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-25 10:41 Dan Carpenter [this message]
2019-10-25 10:53 ` [bug report] RDMA/iw_cxgb4: Avoid touch after free error in ARP failure handlers Potnuri Bharat Teja
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