diff options
author | Alex Estrin <alex.estrin@intel.com> | 2016-02-11 16:30:51 -0500 |
---|---|---|
committer | Doug Ledford <dledford@redhat.com> | 2016-02-12 14:53:22 -0500 |
commit | 08bc327629cbd63bb2f66677e4b33b643695097c (patch) | |
tree | 55f556c8853f61743d31e514957f619be18941d1 /drivers/infiniband/ulp | |
parent | ee50aeac60ba5c4c7e072fbc0c9aa2043c8896e6 (diff) | |
download | linux-08bc327629cbd63bb2f66677e4b33b643695097c.tar.bz2 |
IB/ipoib: fix for rare multicast join race condition
A narrow window for race condition still exist between
multicast join thread and *dev_flush workers.
A kernel crash caused by prolong erratic link state changes
was observed (most likely a faulty cabling):
[167275.656270] BUG: unable to handle kernel NULL pointer dereference at
0000000000000020
[167275.665973] IP: [<ffffffffa05f8f2e>] ipoib_mcast_join+0xae/0x1d0 [ib_ipoib]
[167275.674443] PGD 0
[167275.677373] Oops: 0000 [#1] SMP
...
[167275.977530] Call Trace:
[167275.982225] [<ffffffffa05f92f0>] ? ipoib_mcast_free+0x200/0x200 [ib_ipoib]
[167275.992024] [<ffffffffa05fa1b7>] ipoib_mcast_join_task+0x2a7/0x490
[ib_ipoib]
[167276.002149] [<ffffffff8109d5fb>] process_one_work+0x17b/0x470
[167276.010754] [<ffffffff8109e3cb>] worker_thread+0x11b/0x400
[167276.019088] [<ffffffff8109e2b0>] ? rescuer_thread+0x400/0x400
[167276.027737] [<ffffffff810a5aef>] kthread+0xcf/0xe0
Here was a hit spot:
ipoib_mcast_join() {
..............
rec.qkey = priv->broadcast->mcmember.qkey;
^^^^^^^
.....
}
Proposed patch should prevent multicast join task to continue
if link state change is detected.
Signed-off-by: Alex Estrin <alex.estrin@intel.com>
Changes from v4:
- as suggested by Doug Ledford, optimized spinlock usage,
i.e. ipoib_mcast_join() is called with lock held.
Changes from v3:
- sync with priv->lock before flag check.
Chages from v2:
- Move check for OPER_UP flag state to mcast_join() to
ensure no event worker is in progress.
- minor style fixes.
Changes from v1:
- No need to lock again if error detected.
Signed-off-by: Doug Ledford <dledford@redhat.com>
Diffstat (limited to 'drivers/infiniband/ulp')
-rw-r--r-- | drivers/infiniband/ulp/ipoib/ipoib_multicast.c | 24 |
1 files changed, 17 insertions, 7 deletions
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c index 050dfa175d16..25889311b1e9 100644 --- a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c +++ b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c @@ -456,7 +456,10 @@ out_locked: return status; } -static void ipoib_mcast_join(struct net_device *dev, struct ipoib_mcast *mcast) +/* + * Caller must hold 'priv->lock' + */ +static int ipoib_mcast_join(struct net_device *dev, struct ipoib_mcast *mcast) { struct ipoib_dev_priv *priv = netdev_priv(dev); struct ib_sa_multicast *multicast; @@ -466,6 +469,10 @@ static void ipoib_mcast_join(struct net_device *dev, struct ipoib_mcast *mcast) ib_sa_comp_mask comp_mask; int ret = 0; + if (!priv->broadcast || + !test_bit(IPOIB_FLAG_OPER_UP, &priv->flags)) + return -EINVAL; + ipoib_dbg_mcast(priv, "joining MGID %pI6\n", mcast->mcmember.mgid.raw); rec.mgid = mcast->mcmember.mgid; @@ -525,20 +532,23 @@ static void ipoib_mcast_join(struct net_device *dev, struct ipoib_mcast *mcast) rec.join_state = 4; #endif } + spin_unlock_irq(&priv->lock); multicast = ib_sa_join_multicast(&ipoib_sa_client, priv->ca, priv->port, &rec, comp_mask, GFP_KERNEL, ipoib_mcast_join_complete, mcast); + spin_lock_irq(&priv->lock); if (IS_ERR(multicast)) { ret = PTR_ERR(multicast); ipoib_warn(priv, "ib_sa_join_multicast failed, status %d\n", ret); - spin_lock_irq(&priv->lock); /* Requeue this join task with a backoff delay */ __ipoib_mcast_schedule_join_thread(priv, mcast, 1); clear_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags); spin_unlock_irq(&priv->lock); complete(&mcast->done); + spin_lock_irq(&priv->lock); } + return 0; } void ipoib_mcast_join_task(struct work_struct *work) @@ -620,9 +630,10 @@ void ipoib_mcast_join_task(struct work_struct *work) /* Found the next unjoined group */ init_completion(&mcast->done); set_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags); - spin_unlock_irq(&priv->lock); - ipoib_mcast_join(dev, mcast); - spin_lock_irq(&priv->lock); + if (ipoib_mcast_join(dev, mcast)) { + spin_unlock_irq(&priv->lock); + return; + } } else if (!delay_until || time_before(mcast->delay_until, delay_until)) delay_until = mcast->delay_until; @@ -641,10 +652,9 @@ out: if (mcast) { init_completion(&mcast->done); set_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags); + ipoib_mcast_join(dev, mcast); } spin_unlock_irq(&priv->lock); - if (mcast) - ipoib_mcast_join(dev, mcast); } int ipoib_mcast_start_thread(struct net_device *dev) |