lkml.org 
[lkml]   [2016]   [Mar]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 3.19.y-ckt 162/196] ipv6: addrconf: Fix recursive spin lock call
    Date
    3.19.8-ckt16 -stable review patch.  If anyone has any objections, please let me know.

    ---8<------------------------------------------------------------

    From: "subashab@codeaurora.org" <subashab@codeaurora.org>

    [ Upstream commit 16186a82de1fdd868255448274e64ae2616e2640 ]

    A rcu stall with the following backtrace was seen on a system with
    forwarding, optimistic_dad and use_optimistic set. To reproduce,
    set these flags and allow ipv6 autoconf.

    This occurs because the device write_lock is acquired while already
    holding the read_lock. Back trace below -

    INFO: rcu_preempt self-detected stall on CPU { 1} (t=2100 jiffies
    g=3992 c=3991 q=4471)
    <6> Task dump for CPU 1:
    <2> kworker/1:0 R running task 12168 15 2 0x00000002
    <2> Workqueue: ipv6_addrconf addrconf_dad_work
    <6> Call trace:
    <2> [<ffffffc000084da8>] el1_irq+0x68/0xdc
    <2> [<ffffffc000cc4e0c>] _raw_write_lock_bh+0x20/0x30
    <2> [<ffffffc000bc5dd8>] __ipv6_dev_ac_inc+0x64/0x1b4
    <2> [<ffffffc000bcbd2c>] addrconf_join_anycast+0x9c/0xc4
    <2> [<ffffffc000bcf9f0>] __ipv6_ifa_notify+0x160/0x29c
    <2> [<ffffffc000bcfb7c>] ipv6_ifa_notify+0x50/0x70
    <2> [<ffffffc000bd035c>] addrconf_dad_work+0x314/0x334
    <2> [<ffffffc0000b64c8>] process_one_work+0x244/0x3fc
    <2> [<ffffffc0000b7324>] worker_thread+0x2f8/0x418
    <2> [<ffffffc0000bb40c>] kthread+0xe0/0xec

    v2: do addrconf_dad_kick inside read lock and then acquire write
    lock for ipv6_ifa_notify as suggested by Eric

    Fixes: 7fd2561e4ebdd ("net: ipv6: Add a sysctl to make optimistic
    addresses useful candidates")

    Cc: Eric Dumazet <edumazet@google.com>
    Cc: Erik Kline <ek@google.com>
    Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
    Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
    Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
    Acked-by: Eric Dumazet <edumazet@google.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>
    Signed-off-by: Kamal Mostafa <kamal@canonical.com>
    ---
    net/ipv6/addrconf.c | 5 ++++-
    1 file changed, 4 insertions(+), 1 deletion(-)

    diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
    index ece842c..e0ffd02 100644
    --- a/net/ipv6/addrconf.c
    +++ b/net/ipv6/addrconf.c
    @@ -3214,6 +3214,7 @@ static void addrconf_dad_begin(struct inet6_ifaddr *ifp)
    {
    struct inet6_dev *idev = ifp->idev;
    struct net_device *dev = idev->dev;
    + bool notify = false;

    addrconf_join_solict(dev, &ifp->addr);

    @@ -3259,7 +3260,7 @@ static void addrconf_dad_begin(struct inet6_ifaddr *ifp)
    /* Because optimistic nodes can use this address,
    * notify listeners. If DAD fails, RTM_DELADDR is sent.
    */
    - ipv6_ifa_notify(RTM_NEWADDR, ifp);
    + notify = true;
    }
    }

    @@ -3267,6 +3268,8 @@ static void addrconf_dad_begin(struct inet6_ifaddr *ifp)
    out:
    spin_unlock(&ifp->lock);
    read_unlock_bh(&idev->lock);
    + if (notify)
    + ipv6_ifa_notify(RTM_NEWADDR, ifp);
    }

    static void addrconf_dad_start(struct inet6_ifaddr *ifp)
    --
    2.7.0
    \
     
     \ /
      Last update: 2016-03-09 02:21    [W:3.392 / U:0.080 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site