On 1/14/2020 2:41 PM, Jason Gunthorpe wrote:
On Tue, Jan 14, 2020 at 01:24:00PM -0500, Dennis Dalessandro wrote:
On 1/14/2020 12:00 PM, Dennis Dalessandro wrote:
On 1/14/2020 11:57 AM, Jason Gunthorpe wrote:
On Tue, Jan 14, 2020 at 09:53:45PM +0530,
madhuparnabhowmik04@xxxxxxxxx wrote:
From: Madhuparna Bhowmik <madhuparnabhowmik04@xxxxxxxxx>
list_for_each_entry_rcu has built-in RCU and lock checking.
Pass cond argument to list_for_each_entry_rcu.
Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik04@xxxxxxxxx>
drivers/infiniband/hw/hfi1/verbs.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/infiniband/hw/hfi1/verbs.c
b/drivers/infiniband/hw/hfi1/verbs.c
index 089e201d7550..22f2d4fd2577 100644
+++ b/drivers/infiniband/hw/hfi1/verbs.c
@@ -515,7 +515,7 @@ static inline void hfi1_handle_packet(struct
hfi1_packet *packet,
opa_get_lid(packet->dlid, 9B));
if (!mcast)
goto drop;
- list_for_each_entry_rcu(p, &mcast->qp_list, list) {
+ list_for_each_entry_rcu(p, &mcast->qp_list, list,
lockdep_is_held(&(ibp->rvp.lock))) {
Okay, this looks reasonable
Mike, Dennis, is this the right lock to test?
I'm looking at that right now actually, I don't think this is correct.
Wanted to talk to Mike before I send a response though.
-Denny
That's definitely going to throw a ton of lock dep messages. It's not really
the right lock either. Instead what we probably need to do is what we do in
the non-multicast part of the code and take the rcu_read_lock().
Uh.. why is this using the _rcu varient without holding the rcu lock?
That is quite wrong already.
Yep, seems like a bug to me. Patch forthcoming.
-Denny
