From: Heiko Carstens <Heiko.Carstens@de.ibm.com>
To: Brian King <brking@us.ibm.com>, rusty@rustcorp.com.au
Cc: brking@us.ibm.com, linux-scsi@vger.kernel.org,
linux-scsi-owner@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: call_usermodehelper hang
Date: Fri, 16 Apr 2004 10:52:39 +0200 [thread overview]
Message-ID: <OFD911A46B.B4FA5620-ONC1256E78.002FEC42-C1256E78.0030BCD4@de.ibm.com> (raw)
In-Reply-To: <4072E2F5.9060604@us.ibm.com>
> I have been running into some kernel hangs due to call_usermodehelper.
Looking
> at the backtrace, it looks to me like there are deadlock issues with
adding
> devices from work queues. Attached is a sample backtrace from one of the
> hangs I experienced. My question is why does call_usermodehelper do
> 2 different
> things depending on whether or not it is called from the kevent
> task? It appears
> that the simple way to fix the hang would be to never have
call_usermodehelper
> use a work_queue since it must be called from process context anyway, or
> am I missing something?
Do you have a solution for this problem? As it appears we have the very
same
problem with the zfcp lldd, since we also trigger a scsi_add_device call
by
using schedule_work. IMO the right way to solve this problem would be to
not
trigger any hotplug events while holding a semaphore.
> 0xc0000000017df300 1 0 0 0 D 0xc0000000017df7b0
swapper
> SP(esp) PC(eip) Function(args)
> 0xc00000003fc9f460 0x0000000000000000 NO_SYMBOL or Userspace
> 0xc00000003fc9f4f0 0xc000000000058c40 .schedule +0xb4
> 0xc00000003fc9f5c0 0xc00000000005a464 .wait_for_completion +0x138
> 0xc00000003fc9f6c0 0xc00000000007c594 .call_usermodehelper +0x104
> 0xc00000003fc9f810 0xc00000000022d3e8 .kobject_hotplug +0x3c4
> 0xc00000003fc9f900 0xc00000000022d67c .kobject_add +0x134
> 0xc00000003fc9f9a0 0xc00000000012b3d8 .register_disk +0x70
> 0xc00000003fc9fa40 0xc00000000027dfe4 .add_disk +0x60
> 0xc00000003fc9fad0 0xc0000000002dc7dc .sd_probe +0x290
> 0xc00000003fc9fb80 0xc00000000026fbe8 .bus_match +0x94
> 0xc00000003fc9fc10 0xc00000000026ff70 .driver_attach +0x8c
> 0xc00000003fc9fca0 0xc000000000270104 .bus_add_driver +0x110
> 0xc00000003fc9fd50 0xc000000000270a18 .driver_register +0x38
> 0xc00000003fc9fdd0 0xc0000000002cd8f8 .scsi_register_driver +0x28
> 0xc00000003fc9fe50 0xc0000000004941d8 .init_sd +0x8c
> 0xc00000003fc9fee0 0xc00000000000c720 .init +0x25c
> 0xc00000003fc9ff90 0xc0000000000183ec .kernel_thread +0x4c
>
> 0xc00000003fab3380 4 1 0 0 D 0xc00000003fab3830
events/0
> SP(esp) PC(eip) Function(args)
> 0xc00000003faaf6e0 0x0000000000000000 NO_SYMBOL or Userspace
> 0xc00000003faaf770 0xc000000000058c40 .schedule +0xb4
> 0xc00000003faaf840 0xc00000000022fa20 .rwsem_down_write_failed +0x14c
> 0xc00000003faaf910 0xc00000000026fed0 .bus_add_device +0x11c
> 0xc00000003faaf9b0 0xc00000000026e288 .device_add +0xd0
> 0xc00000003faafa50 0xc0000000002cdb00 .scsi_sysfs_add_sdev +0x8c
> 0xc00000003faafb00 0xc0000000002cbff8 .scsi_probe_and_add_lun +0xb04
> 0xc00000003faafc00 0xc0000000002ccca0 .scsi_add_device +0x90
> 0xc00000003faafcb0 0xc0000000002d9458 .ipr_worker_thread +0xc60
> 0xc00000003faafdc0 0xc00000000007cd9c .worker_thread +0x268
> 0xc00000003faafee0 0xc0000000000839cc .kthread +0x160
> 0xc00000003faaff90 0xc0000000000183ec .kernel_thread +0x4c
next parent reply other threads:[~2004-04-16 8:52 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <4072E2F5.9060604@us.ibm.com>
2004-04-16 8:52 ` Heiko Carstens [this message]
2004-04-16 14:06 ` call_usermodehelper hang Brian King
2005-02-25 17:17 Payasam Manohar
2005-02-25 18:06 ` Lee Revell
-- strict thread matches above, loose matches on Subject: below --
2004-04-06 18:11 Brian King
2004-04-07 0:29 ` Andrew Morton
2004-04-07 6:11 ` Greg KH
2004-04-07 14:00 ` Brian King
2004-04-07 0:41 ` Chris Wright
2004-04-07 1:46 ` Brian King
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