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@xxxxxxxxxx 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.
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