diff options
| author | Feras Daoud <ferasda@mellanox.com> | 2017-03-19 11:18:55 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-03-24 11:00:12 +0100 |
| commit | 7bd191b0a0946f877f4d355e44aa944e6849fd63 (patch) | |
| tree | 6827e31b516bb36ff1a7c72f140420db38cc7ae7 | |
| parent | 67dc18ea69f42802f0087870f886aed397dcf21d (diff) | |
IB/ipoib: Fix deadlock between ipoib_stop and mcast join flow
[ Upstream commit 3e31a490e01a6e67cbe9f6e1df2f3ff0fbf48972 ]
Before calling ipoib_stop, rtnl_lock should be taken, then
the flow clears the IPOIB_FLAG_ADMIN_UP and IPOIB_FLAG_OPER_UP
flags, and waits for mcast completion if IPOIB_MCAST_FLAG_BUSY
is set.
On the other hand, the flow of multicast join task initializes
a mcast completion, sets the IPOIB_MCAST_FLAG_BUSY and calls
ipoib_mcast_join. If IPOIB_FLAG_OPER_UP flag is not set, this
call returns EINVAL without setting the mcast completion and
leads to a deadlock.
ipoib_stop |
| |
clear_bit(IPOIB_FLAG_ADMIN_UP) |
| |
Context Switch |
| ipoib_mcast_join_task
| |
| spin_lock_irq(lock)
| |
| init_completion(mcast)
| |
| set_bit(IPOIB_MCAST_FLAG_BUSY)
| |
| Context Switch
| |
clear_bit(IPOIB_FLAG_OPER_UP) |
| |
spin_lock_irqsave(lock) |
| |
Context Switch |
| ipoib_mcast_join
| return (-EINVAL)
| |
| spin_unlock_irq(lock)
| |
| Context Switch
| |
ipoib_mcast_dev_flush |
wait_for_completion(mcast) |
ipoib_stop will wait for mcast completion for ever, and will
not release the rtnl_lock. As a result panic occurs with the
following trace:
[13441.639268] Call Trace:
[13441.640150] [<ffffffff8168b579>] schedule+0x29/0x70
[13441.641038] [<ffffffff81688fc9>] schedule_timeout+0x239/0x2d0
[13441.641914] [<ffffffff810bc017>] ? complete+0x47/0x50
[13441.642765] [<ffffffff810a690d>] ? flush_workqueue_prep_pwqs+0x16d/0x200
[13441.643580] [<ffffffff8168b956>] wait_for_completion+0x116/0x170
[13441.644434] [<ffffffff810c4ec0>] ? wake_up_state+0x20/0x20
[13441.645293] [<ffffffffa05af170>] ipoib_mcast_dev_flush+0x150/0x190 [ib_ipoib]
[13441.646159] [<ffffffffa05ac967>] ipoib_ib_dev_down+0x37/0x60 [ib_ipoib]
[13441.647013] [<ffffffffa05a4805>] ipoib_stop+0x75/0x150 [ib_ipoib]
Fixes: 08bc327629cb ("IB/ipoib: fix for rare multicast join race condition")
Signed-off-by: Feras Daoud <ferasda@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/infiniband/ulp/ipoib/ipoib_multicast.c | 11 |
1 files changed, 5 insertions, 6 deletions
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c index 6b6826f3e446..8f79caedf905 100644 --- a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c +++ b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c @@ -487,6 +487,9 @@ static int ipoib_mcast_join(struct net_device *dev, struct ipoib_mcast *mcast) !test_bit(IPOIB_FLAG_OPER_UP, &priv->flags)) return -EINVAL; + init_completion(&mcast->done); + set_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags); + ipoib_dbg_mcast(priv, "joining MGID %pI6\n", mcast->mcmember.mgid.raw); rec.mgid = mcast->mcmember.mgid; @@ -645,8 +648,6 @@ void ipoib_mcast_join_task(struct work_struct *work) if (mcast->backoff == 1 || time_after_eq(jiffies, mcast->delay_until)) { /* Found the next unjoined group */ - init_completion(&mcast->done); - set_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags); if (ipoib_mcast_join(dev, mcast)) { spin_unlock_irq(&priv->lock); return; @@ -666,11 +667,9 @@ out: queue_delayed_work(priv->wq, &priv->mcast_task, delay_until - jiffies); } - if (mcast) { - init_completion(&mcast->done); - set_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags); + if (mcast) ipoib_mcast_join(dev, mcast); - } + spin_unlock_irq(&priv->lock); } |