From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brad Campbell Subject: Re: Raid-6 hang on write. Date: Tue, 01 Mar 2005 09:34:01 +0400 Message-ID: <4223FEC9.8070306@wasp.net.au> References: <421DE9A9.4090902@wasp.net.au> <421F4629.5080309@wasp.net.au> <16930.45319.682534.351648@cse.unsw.edu.au> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit In-Reply-To: <16930.45319.682534.351648@cse.unsw.edu.au> Sender: linux-raid-owner@vger.kernel.org To: Neil Brown Cc: lkml , RAID Linux List-Id: linux-raid.ids Neil Brown wrote: > On Friday February 25, brad@wasp.net.au wrote: > >>Turning on debugging in raid6main.c and md.c make it much harder to hit. So I'm assuming something >>timing related. >> >>raid6d --> md_check_recovery --> generic_make_request --> make_request --> get_active_stripe > > > Yes, there is a real problem here. I see if I can figure out the best > way to remedy it... > However I think you reported this problem against a non "-mm" kernel, > and the path from md_check_recovery to generic_make_requests only > exists in "-mm". > > Could you please confirm if there is a problem with > 2.6.11-rc4-bk4->bk10 There is (was). I have three kernels I was testing against. 2.6.11-rc4-bk4, 2.6.11-rc4-bk10 and 2.6.11-rc4-mm1. I moved onto 2.6.11-rc4-mm1 for my main debugging (inserting lots of printks and generally doing stuff that was going to crash). I hope to reproduce the faults against the vanilla 2.6.11-rc4 kernels and I'm now testing with 2.6.11-rc5-bk2. As per the original bug report, 2.6.11-rc4-bk(4/10) locked in [] get_active_stripe+0x224/0x260. Although unlike -mm1 I'm not sure of the sequence of events that caused it and it's not anywhere as easy to hit. I am willing to investigate as time allows however. Testing 2.6.11-rc5-bk2 and it of course is flatly refusing to misbehave. I'll keep beating on it for a couple of days and after writing 3TB with 2.6.11-rc5-bk2, I'll go back to the older kernels and try and reproduce the failure there. It *did* lockup 4 times in a row in get_active_stripe on the older non -mm kernels. Regards, Brad -- "Human beings, who are almost unique in having the ability to learn from the experience of others, are also remarkable for their apparent disinclination to do so." -- Douglas Adams