Re: [PATCH net-next v10 05/11] ipv6: do not call ndisc_send_rs() with write lock
From: Hannes Frederic Sowa <hidden>
Date: 2013-08-28 15:34:52
On Wed, Aug 28, 2013 at 01:22:53PM +0800, Cong Wang wrote:
From: Cong Wang <redacted> Because vxlan module will call ip6_dst_lookup() in TX path, which will hold write lock. So we have to release this write lock before calling ndisc_send_rs(), otherwise could deadlock. Signed-off-by: Cong Wang <redacted>
Change seems fine: Reviewed-by: Hannes Frederic Sowa <redacted>
quoted hunk ↗ jump to hunk
--- net/ipv6/addrconf.c | 10 +++++++--- 1 files changed, 7 insertions(+), 3 deletions(-)diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 8e68466..1bb0861 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c@@ -3088,6 +3088,7 @@ static int addrconf_ifdown(struct net_device *dev, int how) static void addrconf_rs_timer(unsigned long data) { struct inet6_dev *idev = (struct inet6_dev *)data; + struct net_device *dev = idev->dev; struct in6_addr lladdr; write_lock(&idev->lock);@@ -3102,12 +3103,14 @@ static void addrconf_rs_timer(unsigned long data) goto out; if (idev->rs_probes++ < idev->cnf.rtr_solicits) { - if (!__ipv6_get_lladdr(idev, &lladdr, IFA_F_TENTATIVE)) - ndisc_send_rs(idev->dev, &lladdr, + write_unlock(&idev->lock); + if (!ipv6_get_lladdr(dev, &lladdr, IFA_F_TENTATIVE)) + ndisc_send_rs(dev, &lladdr, &in6addr_linklocal_allrouters); else - goto out; + goto put; + write_lock(&idev->lock); /* The wait after the last probe can be shorter */ addrconf_mod_rs_timer(idev, (idev->rs_probes == idev->cnf.rtr_solicits) ?@@ -3123,6 +3126,7 @@ static void addrconf_rs_timer(unsigned long data) out: write_unlock(&idev->lock); +put: in6_dev_put(idev); }
Maybe it would be cleaner to just update a boolean in the inner block and call ndisc_send_rs after the write_unlock. Greetings, Hannes