Re: Intel management, circular locking warning

From: Michael Wang
Date: Tue Nov 20 2012 - 01:26:45 EST

On 11/13/2012 07:03 PM, Denys Fedoryshchenko wrote:
> Hi
>
> Just tried to run latest 3.6.6 32bit kernel on my server farm and got
> circular locking warning:
> Please let me know if you need more information.

Hi, Denys

You can take a try on below patch, it should do some help,
please let me know the result.

Regards,
Michael Wang



diff --git a/drivers/misc/mei/init.c b/drivers/misc/mei/init.c
index 98f1430..d9a74e6 100644
--- a/drivers/misc/mei/init.c
+++ b/drivers/misc/mei/init.c
@@ -120,6 +120,8 @@ static void mei_reset_iamthif_params(struct mei_device *dev)
dev->iamthif_timer = 0;
}

+static struct lock_class_key mei_device_key;
+
/**
* init_mei_device - allocates and initializes the mei device structure
*
@@ -140,6 +142,7 @@ struct mei_device *mei_device_init(struct pci_dev *pdev)
INIT_LIST_HEAD(&dev->wd_cl.link);
INIT_LIST_HEAD(&dev->iamthif_cl.link);
mutex_init(&dev->device_lock);
+ lockdep_set_class(&dev->device_lock, &mei_device_key);
init_waitqueue_head(&dev->wait_recvd_msg);
init_waitqueue_head(&dev->wait_stop_wd);
dev->dev_state = MEI_DEV_INITIALIZING;

>
> [ 4.359176]
> [ 4.359316] ======================================================
> [ 4.359461] [ INFO: possible circular locking dependency detected ]
> [ 4.359612] 3.6.6-build-0063 #21 Not tainted
> [ 4.359763] -------------------------------------------------------
> [ 4.359916] watchdog/1375 is trying to acquire lock:
> [ 4.360060] (&dev->device_lock){+.+.+.}, at: [<f8790075>]
> mei_wd_ops_start+0x2d/0x75 [mei]
> [ 4.360530]
> [ 4.360530] but task is already holding lock:
> [ 4.360770] (&wdd->lock){+.+...}, at: [<c02c9661>]
> watchdog_start+0x19/0x53
> [ 4.361113]
> [ 4.361113] which lock already depends on the new lock.
> [ 4.361113]
> [ 4.361454]
> [ 4.361454] the existing dependency chain (in reverse order) is:
> [ 4.361701]
> [ 4.361701] -> #2 (&wdd->lock){+.+...}:
> [ 4.361841] [<c01608b4>] lock_acquire+0x71/0x85
> [ 4.361845] [<c0360eb8>] __mutex_lock_common+0x44/0x2e2
> [ 4.361848] [<c03611d8>] mutex_lock_nested+0x20/0x22
> [ 4.361850] [<c02c9661>] watchdog_start+0x19/0x53
> [ 4.361851] [<c02c9808>] watchdog_open+0x5c/0xa1
> [ 4.361853] [<c0294000>] misc_open+0xf5/0x14f
> [ 4.361855] [<c01ad941>] chrdev_open+0x106/0x124
> [ 4.361857] [<c01a93fd>] do_dentry_open.clone.16+0x12a/0x1c6
> [ 4.361859] [<c01a94b1>] finish_open+0x18/0x22
> [ 4.361860] [<c01b4d34>] do_last.clone.35+0x6fb/0x865
> [ 4.361862] [<c01b4f37>] path_openat+0x99/0x2c3
> [ 4.361864] [<c01b5380>] do_filp_open+0x26/0x67
> [ 4.361865] [<c01a9efb>] do_sys_open+0x5b/0xe6
> [ 4.361867] [<c01a9fac>] sys_open+0x26/0x2c
> [ 4.361868] [<c0362e31>] syscall_call+0x7/0xb
> [ 4.361870]
> [ 4.361870] -> #1 (misc_mtx){+.+.+.}:
> [ 4.361871] [<c01608b4>] lock_acquire+0x71/0x85
> [ 4.361873] [<c0360eb8>] __mutex_lock_common+0x44/0x2e2
> [ 4.361876] [<c03611d8>] mutex_lock_nested+0x20/0x22
> [ 4.361877] [<c02941aa>] misc_register+0x1f/0xfd
> [ 4.361879] [<c02c9ba7>] watchdog_dev_register+0x22/0xef
> [ 4.361880] [<c02c952f>] watchdog_register_device+0xa0/0x165
> [ 4.361883] [<f87904ff>] mei_watchdog_register+0x13/0x41 [mei]
> [ 4.361885] [<f878d169>]
> mei_interrupt_thread_handler+0x2fd/0x12b8 [mei]
> [ 4.361887] [<c016c553>] irq_thread_fn+0x13/0x25
> [ 4.361888] [<c016c2f8>] irq_thread+0x9e/0x138
> [ 4.361891] [<c0140725>] kthread+0x59/0x5e
> [ 4.361892] [<c0363aba>] kernel_thread_helper+0x6/0xd
> [ 4.361894]
> [ 4.361894] -> #0 (&dev->device_lock){+.+.+.}:
> [ 4.361895] [<c016026e>] __lock_acquire+0x9a3/0xc27
> [ 4.361897] [<c01608b4>] lock_acquire+0x71/0x85
> [ 4.361898] [<c0360eb8>] __mutex_lock_common+0x44/0x2e2
> [ 4.361900] [<c03611d8>] mutex_lock_nested+0x20/0x22
> [ 4.361902] [<f8790075>] mei_wd_ops_start+0x2d/0x75 [mei]
> [ 4.361904] [<c02c967f>] watchdog_start+0x37/0x53
> [ 4.361905] [<c02c9808>] watchdog_open+0x5c/0xa1
> [ 4.361907] [<c0294000>] misc_open+0xf5/0x14f
> [ 4.361908] [<c01ad941>] chrdev_open+0x106/0x124
> [ 4.361909] [<c01a93fd>] do_dentry_open.clone.16+0x12a/0x1c6
> [ 4.361910] [<c01a94b1>] finish_open+0x18/0x22
> [ 4.361912] [<c01b4d34>] do_last.clone.35+0x6fb/0x865
> [ 4.361914] [<c01b4f37>] path_openat+0x99/0x2c3
> [ 4.361915] [<c01b5380>] do_filp_open+0x26/0x67
> [ 4.361916] [<c01a9efb>] do_sys_open+0x5b/0xe6
> [ 4.361918] [<c01a9fac>] sys_open+0x26/0x2c
> [ 4.361919] [<c0362e31>] syscall_call+0x7/0xb
> [ 4.361919]
> [ 4.361919] other info that might help us debug this:
> [ 4.361919]
> [ 4.361921] Chain exists of:
> [ 4.361921] &dev->device_lock --> misc_mtx --> &wdd->lock
> [ 4.361921]
> [ 4.361921] Possible unsafe locking scenario:
> [ 4.361921]
> [ 4.361922] CPU0 CPU1
> [ 4.361922] ---- ----
> [ 4.361923] lock(&wdd->lock);
> [ 4.361924] lock(misc_mtx);
> [ 4.361924] lock(&wdd->lock);
> [ 4.361925] lock(&dev->device_lock);
> [ 4.361926]
> [ 4.361926] *** DEADLOCK ***
> [ 4.361926]
> [ 4.361926] 2 locks held by watchdog/1375:
> [ 4.361929] #0: (misc_mtx){+.+.+.}, at: [<c0293f28>]
> misc_open+0x1d/0x14f
> [ 4.361931] #1: (&wdd->lock){+.+...}, at: [<c02c9661>]
> watchdog_start+0x19/0x53
> [ 4.361932]
> [ 4.361932] stack backtrace:
> [ 4.361933] Pid: 1375, comm: watchdog Not tainted 3.6.6-build-0063 #21
> [ 4.361933] Call Trace:
> [ 4.361936] [<c015ec57>] print_circular_bug+0x1ac/0x1b6
> [ 4.361937] [<c016026e>] __lock_acquire+0x9a3/0xc27
> [ 4.361940] [<c015f736>] ? mark_lock+0x26/0x1bb
> [ 4.361941] [<c01608b4>] lock_acquire+0x71/0x85
> [ 4.361943] [<f8790075>] ? mei_wd_ops_start+0x2d/0x75 [mei]
> [ 4.361945] [<c0360eb8>] __mutex_lock_common+0x44/0x2e2
> [ 4.361947] [<f8790075>] ? mei_wd_ops_start+0x2d/0x75 [mei]
> [ 4.361949] [<c036114c>] ? __mutex_lock_common+0x2d8/0x2e2
> [ 4.361951] [<c0160c8d>] ? trace_hardirqs_on_caller+0x10e/0x13f
> [ 4.361953] [<c03611d8>] mutex_lock_nested+0x20/0x22
> [ 4.361955] [<f8790075>] ? mei_wd_ops_start+0x2d/0x75 [mei]
> [ 4.361957] [<f8790075>] mei_wd_ops_start+0x2d/0x75 [mei]
> [ 4.361959] [<c02c967f>] watchdog_start+0x37/0x53
> [ 4.361960] [<c02c9808>] watchdog_open+0x5c/0xa1
> [ 4.361962] [<c0294000>] misc_open+0xf5/0x14f
> [ 4.361963] [<c01ad941>] chrdev_open+0x106/0x124
> [ 4.361964] [<c01ad83b>] ? cdev_put+0x1a/0x1a
> [ 4.361966] [<c01a93fd>] do_dentry_open.clone.16+0x12a/0x1c6
> [ 4.361967] [<c01a94b1>] finish_open+0x18/0x22
> [ 4.361969] [<c01b4d34>] do_last.clone.35+0x6fb/0x865
> [ 4.361970] [<c01b2f73>] ? inode_permission+0x3f/0x41
> [ 4.361972] [<c01b4f37>] path_openat+0x99/0x2c3
> [ 4.361974] [<c01b5380>] do_filp_open+0x26/0x67
> [ 4.361977] [<c01be06c>] ? alloc_fd+0xb7/0xc2
> [ 4.361979] [<c01a9efb>] do_sys_open+0x5b/0xe6
> [ 4.361980] [<c01a9fac>] sys_open+0x26/0x2c
> [ 4.361981] [<c0362e31>] syscall_call+0x7/0xb
>
>
>
> ---
> Denys Fedoryshchenko, Network Engineer, Virtual ISP S.A.L.
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