[LU-1878] NULL pointer in ll_readahead()

• Type: Bug
• Resolution: Won't Fix
• Priority: Minor
• Affects Version/s: Lustre 1.8.x (1.8.0 - 1.8.5)
• Severity: 3
• Bugzilla ID: 24,376

Epic

client

• Assignee: Bob Glossman (Inactive)
• Reporter: Vladimir V. Saveliev

Description

Kernel OOPS on a client

<1>[1740431.005226] BUG: unable to handle kernel NULL pointer dereference at (null)
<1>[1740431.008694] IP: [<ffffffffa0a9dfda>] ll_readahead+0x4a/0x1d20 [lustre]
<4>[1740431.008694] PGD 2cffabf5067 PUD 2cffabf4067 PMD 0
<0>[1740431.008694] Oops: 0000 1 SMP
<0>[1740431.008694] last sysfs file: /sys/devices/system/node/node63/meminfo
[archkdbcommon]kdb> -bt

Stack traceback for pid 839153
0xffff8acffbd72600 000000 000000 0 000 R 0xffff8acffbd72c90 *magic.exe
[<ffffffffa0a9dfda>] ll_readahead+0x4a/0x1d20 [lustre]
[<ffffffffa0aa0ebb>] ll_readpage+0x120b/0x1760 [lustre]
[<ffffffff810b5cf1>] filemap_fault+0x241/0x3d0
[<ffffffffa0aaebd7>] ll_fault+0x3b7/0xdd0 [lustre]
[<ffffffff810ceae7>] __do_fault+0x57/0x520
[<ffffffff810d3459>] handle_mm_fault+0x199/0x430
[<ffffffff8139dcaf>] do_page_fault+0x1bf/0x3e0
[<ffffffff8139b5cf>] page_fault+0x1f/0x30
[<0000000000472d64>] 0x472d64

Issue Links

• Trackbacks: Lustre 1.8.x known issues tracker While testing against Lustre b18 branch, we would hit known bugs which were already reported in Lustre Bugzilla https://bugzilla.lustre.org/. In order to move away from relying on Bugzilla, we would create a JIRA

Comments

[Andreas Dilger]

Close old ticket.

[Vladimir V. Saveliev]

http://review.whamcloud.com/4026

this is updated version accordingly to Jinshan Xiong's inspection.

[Peter Jones]

Excellent - thanks Vladimir! Don't worry about the inspectors - we'll organize that.

Bob

Could you please take care of landing this patch and check in particular its applicability to the master branch

Thanks

Peter

[Vladimir V. Saveliev]

the patch is in gerrit (http://review.whamcloud.com/3927), however, I
am not sure about inspectors, please advise.

[Vladimir V. Saveliev]

http://review.whamcloud.com/3927

[Peter Jones]

Great! It sounds like you are on the right track. Once the patch is in gerrit then you should post the URL to the changeset as a comment in the JIRA ticket. Thanks!

[Vladimir V. Saveliev]

Hello, Peter

That is what I was planning to do next. From http://wiki.whamcloud.com/display/PUB/Submitting+Changes
I realised that JIRA ticket needs to be created first. So, I created
LU-1878.

I hope that my patch matches
2. Test and commit your patch locally using acceptance-small.sh and
3. The patch follows the Requirements for patch submission:
and I was going to do 4. The patch has been uploaded to Gerrit. On
that step I guess that I am to git push the patch somewhere.

If I went wrong way or there is simple way, please get someone to help
me.

TIA
Best regards,
Vladimir

[Peter Jones]

Thanks for the patch Vladimir. Could you please upload it into gerrit so that we can review and test it? There are instructions on the whamcloud wiki or I can get an engineer to step you through the process if that helps.