[4.2.y-ckt stable] Patch "IB/cm: Fix a recently introduced deadlock" has been added to the 4.2.y-ckt tree
Kamal Mostafa
kamal at canonical.com
Wed Jan 27 00:13:02 UTC 2016
This is a note to let you know that I have just added a patch titled
IB/cm: Fix a recently introduced deadlock
to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree
which can be found at:
http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue
This patch is scheduled to be released in version 4.2.8-ckt3.
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Kamal
---8<------------------------------------------------------------
>From 15236ba57e9137838965854ed7dd263740fa03e9 Mon Sep 17 00:00:00 2001
From: Bart Van Assche <bart.vanassche at sandisk.com>
Date: Fri, 1 Jan 2016 13:17:46 +0100
Subject: IB/cm: Fix a recently introduced deadlock
commit 4bfdf635c668869c69fd18ece37ec66fb6f38fcf upstream.
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:
Acked-by: Erez Shitrit <erezsh at mellanox.com>
=================================
[ 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.vanassche at sandisk.com>
Cc: Erez Shitrit <erezsh at mellanox.com>
Signed-off-by: Doug Ledford <dledford at redhat.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
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 8be7352..27919bb 100644
--- a/drivers/infiniband/core/cm.c
+++ b/drivers/infiniband/core/cm.c
@@ -826,11 +826,11 @@ 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;
}
--
1.9.1
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