Re: RCU'ed dst_get_neighbour()

Marc Aurele La France
2011-11-29T22:32:35Z

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On Tue, 29 Nov 2011, Eric Dumazet wrote:

> Le mardi 29 novembre 2011 à 22:17 +0100, Eric Dumazet a écrit :
>> Le mardi 29 novembre 2011 à 14:00 -0700, Marc Aurele La France a écrit :
>>> On Tue, 29 Nov 2011, Eric Dumazet wrote:
>>>> Oh well, I forgot one rcu_read_unlock(), I'll send a V2...

>>> This also doesn't address the other dst_get_neighbour() instances
>>> introduced by
>>> http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=commitdiff;h=69cce1d1404968f78b177a0314f5822d5afdbbfb

>> Oh well, a complete audit is needed, and I have no choice but doing it.

> Here is the result of this audit, please double check and test it, I
> only compiled this.

> [PATCH V2] drivers/infiniband: fix lockdep splats

> commit f2c31e32b37 (net: fix NULL dereferences in check_peer_redir())
> forgot to take care of infiniband uses of dst neighbours.

> Many thanks to Marc Aurele who provided a nice bug report and feedback.

> Reported-by: Marc Aurele La France <tsi-yfeSBMgouQgsA/PxXw9srA@public.gmane.org>
> Signed-off-by: Eric Dumazet <eric.dumazet-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> CC: David Miller <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>
> CC: Roland Dreier <roland-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
> ---
> drivers/infiniband/core/addr.c | 9 +++++--
> drivers/infiniband/hw/cxgb3/iwch_cm.c | 4 +++
> drivers/infiniband/hw/cxgb4/cm.c | 6 +++++
> drivers/infiniband/hw/nes/nes_cm.c | 6 +++--
> drivers/infiniband/ulp/ipoib/ipoib_main.c | 18 +++++++++------
> drivers/infiniband/ulp/ipoib/ipoib_multicast.c | 6 +++--
> 6 files changed, 35 insertions(+), 14 deletions(-)

This looks good to me, although I'm a little iffy on your use of
dst_get_neighbour_raw(), but that could be just me.

But your audit is incomplete, a grep of 3.1.3 for dst_get_neighbour() and
dst_get_neighbour_raw() reveals occurrences in ...

drivers/scsi/cxgbi/cxgb3i/cxgb3i.c
drivers/scsi/cxgbi/cxgb4i/cxgb4i.c
drivers/scsi/cxgbi/libcxgbi.c
drivers/s390/net/qeth_l3_main.c
drivers/net/cxgb3/cxgb3_offload.c
drivers/infiniband/hw/cxgb3/iwch_cm.c
drivers/infiniband/hw/nes/nes_cm.c
drivers/infiniband/hw/cxgb4/cm.c
drivers/infiniband/core/addr.c
drivers/infiniband/ulp/ipoib/ipoib_main.c
drivers/infiniband/ulp/ipoib/ipoib_multicast.c
include/net/dst.h
net/atm/clip.c
net/sched/sch_teql.c
net/core/neighbour.c
net/ipv4/ip_gre.c
net/ipv4/ip_output.c
net/ipv4/route.c
net/xfrm/xfrm_policy.c
net/bridge/br_netfilter.c
net/decnet/dn_neigh.c
net/decnet/dn_route.c
net/ipv6/sit.c
net/ipv6/addrconf.c
net/ipv6/route.c
net/ipv6/ndisc.c
net/ipv6/ip6_output.c
net/ipv6/ip6_fib.c

(I'd list them all here, but I'm having issues with my MUA when I do so.)

Marc.

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