From: Douglas Gilbert <dgilbert@interlog.com>
To: vaughan <vaughan.cao@oracle.com>, Madper Xie <cxie@redhat.com>
Cc: linux-kernel@vger.kernel.org,
SCSI development list <linux-scsi@vger.kernel.org>
Subject: Re: [Bug] 12.864681 BUG: lock held when returning to user space!
Date: Tue, 08 Oct 2013 09:45:35 -0400 [thread overview]
Message-ID: <52540C7F.8050207@interlog.com> (raw)
In-Reply-To: <5253A9E7.5030707@oracle.com>
On 13-10-08 02:44 AM, vaughan wrote:
> Hi Madper,
>
> CC to Douglas to get comments.
> I use the rw_semaphore o_sem to protect excl open, introduced in commit
> 15b06f9a02406e5460001db6d5af5c738cd3d4e7 since v3.12-rc1.
> Is it forbidden to do like that in kernel?...
It appears you can not (allow sg_open() to hold a semaphore
then return to the user space). So you will need to do some
rework on that patch or revert it.
Doug Gilbert
Reference: scsi-linux + kernel lists, title:
[PATCH v6 0/4][SCSI] sg: fix race condition in sg_open
20130828
> On 10/08/2013 01:57 PM, Madper Xie wrote:
>> Howdy Vaughan Cao,
>> I can't meet this issue on both 3.11 and 3.11.4. There are only four
>> patches between 3.11 and 3.12-rc2 and you are the author. Will you
>> please check them if you have time.
>>
>> cxie@redhat.com writes:
>>
>>> Hi all,
>>> With kernel3.12-rc2 the dmesg shows following logs:
>>> [ 12.864680] ================================================
>>> [ 12.864681] [ BUG: lock held when returning to user space! ]
>>> [ 12.864682] 3.12.0-rc2 #1 Not tainted
>>> [ 12.864683] ------------------------------------------------
>>> [ 12.864684] iprinit/719 is leaving the kernel with locks still held!
>>> [ 12.864685] 1 lock held by iprinit/719:
>>> [ 12.864686] #0: (&sdp->o_sem){.+.+..}, at: [<ffffffffa050de05>] sg_open+0x4b5/0x644 [sg]
>>> [ 12.934954] ath9k 0000:01:00.0: enabling device (0000 -> 0002)
>>> [ 12.940346] ath: phy0: timeout (1000 us) on reg 0x15f18: 0x00000000 & 0x00000007 != 0x00000004
>>> [ 12.943125] ath: EEPROM regdomain: 0x60
>>> [ 12.943127] ath: EEPROM indicates we should expect a direct regpair map
>>> [ 12.943129] ath: Country alpha2 being used: 00
>>> [ 12.943130] ath: Regpair used: 0x60
>>> [ 12.960202] r8169 0000:02:00.0 p3p1: link down
>>> [ 12.960236] r8169 0000:02:00.0 p3p1: link down
>>> [ 12.960256] IPv6: ADDRCONF(NETDEV_UP): p3p1: link is not ready
>>> [ 13.003523] ieee80211 phy0: Selected rate control algorithm 'minstrel_ht'
>>> [ 13.003886] ieee80211 phy0: Atheros AR9485 Rev:1 mem=0xffffc9000bc80000, irq=16
>>> [ 13.012120] ip6_tables: (C) 2000-2006 Netfilter Core Team
>>> [ 13.023667] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
>>> [ 13.055802] Ebtables v2.0 registered
>>> [ 13.192291] nf_conntrack version 0.5.0 (16384 buckets, 65536 max)
>>> [ 15.906392] r8169 0000:02:00.0 p3p1: link up
>>> [ 15.906416] IPv6: ADDRCONF(NETDEV_CHANGE): p3p1: link becomes ready
>>> [ 17.121989] systemd-udevd (334) used greatest stack depth: 3352 bytes left
>>>
>>> I'm working on finding which version bring this bug in.
>>
>
>
next prev parent reply other threads:[~2013-10-08 13:45 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-30 7:02 [Bug] 12.864681 BUG: lock held when returning to user space! Madper Xie
2013-10-08 5:57 ` Madper Xie
2013-10-08 6:44 ` vaughan
2013-10-08 13:45 ` Douglas Gilbert [this message]
2013-10-16 13:24 ` James Bottomley
2013-10-16 22:41 ` Douglas Gilbert
2013-10-17 2:52 ` vaughan
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