On Fri, Jan 1, 2016 at 2:17 PM, Bart Van Assche
<bart.vanass...@sandisk.com> wrote:
> ib_send_cm_drep() calls cm_enter_timewait() while holding a spinlock
> that can be locked from inside an interrupt handler. Hence do not
> enable interrupts inside cm_enter_timewait() if called with interrupts
> disabled.
>
> This patch fixes e.g. the following deadlock:
>
> =================================
> [ INFO: inconsistent lock state ]
> 4.4.0-rc7+ #1 Tainted: G E
> ---------------------------------
> inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage.
> swapper/8/0 [HC1[1]:SC0[0]:HE0:SE1] takes:
> (&(&cm_id_priv->lock)->rlock){?.+...}, at: [<ffffffffa036eec4>]
> cm_establish+0x
> 74/0x1b0 [ib_cm]
> {HARDIRQ-ON-W} state was registered at:
> [<ffffffff810a3c11>] mark_held_locks+0x71/0x90
> [<ffffffff810a3e87>] trace_hardirqs_on_caller+0xa7/0x1c0
> [<ffffffff810a3fad>] trace_hardirqs_on+0xd/0x10
> [<ffffffff8151c40b>] _raw_spin_unlock_irq+0x2b/0x40
> [<ffffffffa036ea8e>] cm_enter_timewait+0xae/0x100 [ib_cm]
> [<ffffffffa036ff76>] ib_send_cm_drep+0xb6/0x190 [ib_cm]
> [<ffffffffa052ed08>] srp_cm_handler+0x128/0x1a0 [ib_srp]
> [<ffffffffa0370340>] cm_process_work+0x20/0xf0 [ib_cm]
> [<ffffffffa0371335>] cm_dreq_handler+0x135/0x2c0 [ib_cm]
> [<ffffffffa03733c5>] cm_work_handler+0x75/0xd0 [ib_cm]
> [<ffffffff8107184d>] process_one_work+0x1bd/0x460
> [<ffffffff81073148>] worker_thread+0x118/0x420
> [<ffffffff81078454>] kthread+0xe4/0x100
> [<ffffffff8151cbbf>] ret_from_fork+0x3f/0x70
> irq event stamp: 1672286
> hardirqs last enabled at (1672283): [<ffffffff81408ec0>] poll_idle+0x10/0x80
> hardirqs last disabled at (1672284): [<ffffffff8151d304>]
> common_interrupt+0x84/0x89
> softirqs last enabled at (1672286): [<ffffffff8105b4dc>]
> _local_bh_enable+0x1c/0x50
> softirqs last disabled at (1672285): [<ffffffff8105b697>] irq_enter+0x47/0x70
>
> other info that might help us debug this:
> Possible unsafe locking scenario:
>
> CPU0
> ----
> lock(&(&cm_id_priv->lock)->rlock);
> <Interrupt>
> lock(&(&cm_id_priv->lock)->rlock);
>
> *** DEADLOCK ***
>
> no locks held by swapper/8/0.
>
> stack backtrace:
> CPU: 8 PID: 0 Comm: swapper/8 Tainted: G E 4.4.0-rc7+ #1
> Hardware name: Dell Inc. PowerEdge R430/03XKDV, BIOS 1.0.2 11/17/2014
> ffff88045af5e950 ffff88046e503a88 ffffffff81251c1b 0000000000000007
> 0000000000000006 0000000000000003 ffff88045af5ddc0 ffff88046e503ad8
> ffffffff810a32f4 0000000000000000 0000000000000000 0000000000000001
> Call Trace:
> <IRQ> [<ffffffff81251c1b>] dump_stack+0x4f/0x74
> [<ffffffff810a32f4>] print_usage_bug+0x184/0x190
> [<ffffffff810a36e2>] mark_lock_irq+0xf2/0x290
> [<ffffffff810a3995>] mark_lock+0x115/0x1b0
> [<ffffffff810a3b8c>] mark_irqflags+0x15c/0x170
> [<ffffffff810a4fef>] __lock_acquire+0x1ef/0x560
> [<ffffffff810a53c2>] lock_acquire+0x62/0x80
> [<ffffffff8151bd33>] _raw_spin_lock_irqsave+0x43/0x60
> [<ffffffffa036eec4>] cm_establish+0x74/0x1b0 [ib_cm]
> [<ffffffffa036f031>] ib_cm_notify+0x31/0x100 [ib_cm]
> [<ffffffffa0637f24>] srpt_qp_event+0x54/0xd0 [ib_srpt]
> [<ffffffffa0196052>] mlx4_ib_qp_event+0x72/0xc0 [mlx4_ib]
> [<ffffffffa00775b9>] mlx4_qp_event+0x69/0xd0 [mlx4_core]
> [<ffffffffa006000e>] mlx4_eq_int+0x51e/0xd50 [mlx4_core]
> [<ffffffffa006084f>] mlx4_msi_x_interrupt+0xf/0x20 [mlx4_core]
> [<ffffffff810b67b0>] handle_irq_event_percpu+0x40/0x110
> [<ffffffff810b68bf>] handle_irq_event+0x3f/0x70
> [<ffffffff810ba7f9>] handle_edge_irq+0x79/0x120
> [<ffffffff81007f3d>] handle_irq+0x5d/0x130
> [<ffffffff810071fd>] do_IRQ+0x6d/0x130
> [<ffffffff8151d309>] common_interrupt+0x89/0x89
> <EOI> [<ffffffff8140895f>] cpuidle_enter_state+0xcf/0x200
> [<ffffffff81408aa2>] cpuidle_enter+0x12/0x20
> [<ffffffff810990d6>] call_cpuidle+0x36/0x60
> [<ffffffff81099163>] cpuidle_idle_call+0x63/0x110
> [<ffffffff8109930a>] cpu_idle_loop+0xfa/0x130
> [<ffffffff8109934e>] cpu_startup_entry+0xe/0x10
> [<ffffffff8103c443>] start_secondary+0x83/0x90
>
> Fixes: commit be4b499323bf ("IB/cm: Do not queue work to a device that's
> going away")
> Signed-off-by: Bart Van Assche <bart.vanass...@sandisk.com>
Acked-by: Erez Shitrit <ere...@mellanox.com>
> Cc: Erez Shitrit <ere...@mellanox.com>
> Cc: stable <sta...@vger.kernel.org>
> ---
> drivers/infiniband/core/cm.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c
> index 0a26dd6..d6d2b35 100644
> --- a/drivers/infiniband/core/cm.c
> +++ b/drivers/infiniband/core/cm.c
> @@ -782,11 +782,11 @@ static void cm_enter_timewait(struct cm_id_private
> *cm_id_priv)
> wait_time = cm_convert_to_ms(cm_id_priv->av.timeout);
>
> /* Check if the device started its remove_one */
> - spin_lock_irq(&cm.lock);
> + spin_lock_irqsave(&cm.lock, flags);
> if (!cm_dev->going_down)
> queue_delayed_work(cm.wq,
> &cm_id_priv->timewait_info->work.work,
> msecs_to_jiffies(wait_time));
> - spin_unlock_irq(&cm.lock);
> + spin_unlock_irqrestore(&cm.lock, flags);
>
> cm_id_priv->timewait_info = NULL;
> }
> --
> 2.1.4
>
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