Messages in this thread | | | Subject | Re: [PATCH v3] RDMA/core: Fix race when resolving IP address | From | Dag Moxnes <> | Date | Mon, 8 Jul 2019 20:47:38 +0200 |
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Thanks Jason,
Regards, Dag
Den 08.07.2019 19:50, skrev Jason Gunthorpe: > On Mon, Jul 08, 2019 at 01:16:24PM +0200, Dag Moxnes 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. >> >> This will cause the race shown it the following sample trace: >> >> rdma_resolve_addr() >> rdma_resolve_ip() >> addr_resolve() >> addr_resolve_neigh() >> fetch_ha() >> dst_fetch_ha() >> n->nud_state == NUD_VALID > It isn't nud_state that is the problem here, it is the parallel > memcpy's onto ha. I fixed the commit message > > This could also have been solved by using the ha_lock, but I don't > think we have a reason to particularly over-optimize this. > >> drivers/infiniband/core/addr.c | 9 ++++++--- >> 1 file changed, 6 insertions(+), 3 deletions(-) > Applied to for-next, thanks > > Jason
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