Messages in this thread | | | Date | Tue, 9 Jul 2019 09:26:06 -0300 | From | Jason Gunthorpe <> | Subject | Re: [PATCH v2] RDMA/core: Fix race when resolving IP address |
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On Fri, Jul 05, 2019 at 07:09:50AM +0300, Leon Romanovsky wrote: > On Fri, Jul 05, 2019 at 07:49:06AM +0530, Parav Pandit wrote: > > On Fri, Jun 28, 2019 at 2:20 PM Dag Moxnes <dag.moxnes@oracle.com> wrote: > > > > > > Use neighbour lock when copying MAC address from neighbour data struct > > > in dst_fetch_ha. > > > > > > When not using the lock, it is possible for the function to race with > > > neigh_update, causing it to copy an invalid MAC address. > > > > > > It is possible to provoke this error by calling rdma_resolve_addr in a > > > tight loop, while deleting the corresponding ARP entry in another tight > > > loop. > > > > > > Signed-off-by: Dag Moxnes <dag.moxnes@oracle.com> > > > Signed-off-by: Håkon Bugge <haakon.bugge@oracle.com> > > > > > > v1 -> v2: > > > * Modified implementation to improve readability > > > drivers/infiniband/core/addr.c | 9 ++++++--- > > > 1 file changed, 6 insertions(+), 3 deletions(-) > > > > > > diff --git a/drivers/infiniband/core/addr.c b/drivers/infiniband/core/addr.c > > > index 2f7d141598..51323ffbc5 100644 > > > +++ b/drivers/infiniband/core/addr.c > > > @@ -333,11 +333,14 @@ static int dst_fetch_ha(const struct dst_entry *dst, > > > if (!n) > > > return -ENODATA; > > > > > > - if (!(n->nud_state & NUD_VALID)) { > > > + read_lock_bh(&n->lock); > > > + if (n->nud_state & NUD_VALID) { > > > + memcpy(dev_addr->dst_dev_addr, n->ha, MAX_ADDR_LEN); > > > + read_unlock_bh(&n->lock); > > > + } else { > > > + read_unlock_bh(&n->lock); > > > neigh_event_send(n, NULL); > > > ret = -ENODATA; > > > - } else { > > > - memcpy(dev_addr->dst_dev_addr, n->ha, MAX_ADDR_LEN); > > > } > > > > > > neigh_release(n); > > > > > Reviewed-by: Parav Pandit <parav@mellanox.com> > > > > A sample trace such as below in commit message would be good to have. > > Or the similar one that you noticed with ARP delete sequence. > > > > neigh_changeaddr() > > neigh_flush_dev() > > n->nud_state = NUD_NOARP; > > > > Having some issues with office outlook, so replying via gmail. > > Your replies from gmail looks much better when you used Outlook - proper > spacing between quoted text and your reply.
Why not use thunderbird or something?
Jason
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