Bug 198845 - initrd's raidautorun brings up degraded raid devices because of limit on 127 auto-detect raid members
Summary: initrd's raidautorun brings up degraded raid devices because of limit on 127 ...
Alias: None
Product: Fedora
Classification: Fedora
Component: kernel
Version: rawhide
Hardware: All
OS: Linux
Target Milestone: ---
Assignee: Kernel Maintainer List
QA Contact: Brian Brock
Whiteboard: bzcl34nup
Depends On:
TreeView+ depends on / blocked
Reported: 2006-07-14 00:16 UTC by Alexandre Oliva
Modified: 2008-04-04 05:53 UTC (History)
2 users (show)

Clone Of:
Last Closed: 2008-04-04 05:53:30 UTC

Attachments (Terms of Use)
Patch that fixes the bug (1.73 KB, patch)
2006-07-30 06:10 UTC, Alexandre Oliva
no flags Details | Diff
Patch that avoids crashes on out-of-memory (3.31 KB, patch)
2006-07-30 06:37 UTC, Alexandre Oliva
no flags Details | Diff

Description Alexandre Oliva 2006-07-14 00:16:08 UTC
Description of problem:
md/md.c has a limit of 127 detected devices.  I've accidentally exceeded this
limit by one, and now my box always comes up with the last raid6 array missing
one disk.  Would it be a bad idea to turn this fixed-size array into a
dynamically-allocated list?

Version-Release number of selected component (if applicable):

How reproducible:
Every time

Steps to Reproduce:
1.Create exactly 128 partitions of about the same size, and set up say 64 pairs
of raid 1 devices
2.Arrange for raidautorun to be in initrd's init
Actual results:
The last array will be missing a member

Expected results:
It shouldn't

Additional info:

Comment 1 Alexandre Oliva 2006-07-30 06:10:14 UTC
Created attachment 133288 [details]
Patch that fixes the bug

Turning the fixed-size array into a list works.  It also fixes a race condition
in the increment-and-use-old-value of dev_cnt.	The compiler certainly won't do
it atomically, and it's actually expensive to generate code that does this

Comment 2 Alexandre Oliva 2006-07-30 06:37:37 UTC
Created attachment 133289 [details]
Patch that avoids crashes on out-of-memory

I realized I failed to check the result of kzalloc.  This patch fixes it,
adjusting for an error message with the name of the device to be printed when
this happens (which AFAICT only the callers have).

Comment 3 Dave Jones 2007-04-23 18:45:05 UTC
please post this upstream to linux-kernel@vger.kernel.org

Comment 4 Bug Zapper 2008-04-03 17:47:25 UTC
Based on the date this bug was created, it appears to have been reported
against rawhide during the development of a Fedora release that is no
longer maintained. In order to refocus our efforts as a project we are
flagging all of the open bugs for releases which are no longer
maintained. If this bug remains in NEEDINFO thirty (30) days from now,
we will automatically close it.

If you can reproduce this bug in a maintained Fedora version (7, 8, or
rawhide), please change this bug to the respective version and change
the status to ASSIGNED. (If you're unable to change the bug's version
or status, add a comment to the bug and someone will change it for you.)

Thanks for your help, and we apologize again that we haven't handled
these issues to this point.

The process we're following is outlined here:

We will be following the process here:
http://fedoraproject.org/wiki/BugZappers/HouseKeeping to ensure this
doesn't happen again.

Comment 5 Alexandre Oliva 2008-04-04 05:53:30 UTC
Patch was posted upstream, I don't know whether it made it, but we now use
mdadm, which doesn't run into the limitations, so we're fine.

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