From: Kaike Wan <kaike.wan@xxxxxxxxx>
It was found by Saurabh Sengar that the netlink code tried to allocate
memory with GFP_KERNEL while holding a spinlock. While it is possible
to fix the issue by replacing GFP_KERNEL with GFP_ATOMIC, it is better
to get rid of the spinlock while sending the packet. However, in order
to protect against a race condition that a quick response may be received
before the request is put on the request list, we need to put the request
on the list first.
Signed-off-by: Kaike Wan <kaike.wan@xxxxxxxxx>
---
drivers/infiniband/core/sa_query.c | 22 ++++++++++++----------
1 files changed, 12 insertions(+), 10 deletions(-)
diff --git a/drivers/infiniband/core/sa_query.c b/drivers/infiniband/core/sa_query.c
index edcf568..240b57c 100644
--- a/drivers/infiniband/core/sa_query.c
+++ b/drivers/infiniband/core/sa_query.c
@@ -562,23 +562,25 @@ static int ib_nl_make_request(struct ib_sa_query *query)
INIT_LIST_HEAD(&query->list);
query->seq = (u32)atomic_inc_return(&ib_nl_sa_request_seq);
+ /* Put the request on the list first.*/
spin_lock_irqsave(&ib_nl_request_lock, flags);
+ delay = msecs_to_jiffies(sa_local_svc_timeout_ms);
+ query->timeout = delay + jiffies;
+ list_add_tail(&query->list, &ib_nl_request_list);
+ spin_unlock_irqrestore(&ib_nl_request_lock, flags);
+
ret = ib_nl_send_msg(query);
+ spin_lock_irqsave(&ib_nl_request_lock, flags);
if (ret <= 0) {
ret = -EIO;
- goto request_out;
+ /* Remove the request */
+ list_del(&query->list);
} else {
ret = 0;
+ /* Start the timeout if this is the only request */
+ if (ib_nl_request_list.next == &query->list)
+ queue_delayed_work(ib_nl_wq, &ib_nl_timed_work, delay);
}
-
- delay = msecs_to_jiffies(sa_local_svc_timeout_ms);
- query->timeout = delay + jiffies;
- list_add_tail(&query->list, &ib_nl_request_list);
- /* Start the timeout if this is the only request */
- if (ib_nl_request_list.next == &query->list)
- queue_delayed_work(ib_nl_wq, &ib_nl_timed_work, delay);
-
-request_out:
spin_unlock_irqrestore(&ib_nl_request_lock, flags);
return ret;
--
1.7.1
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