Bug 143069 - [xen] [panic] Xen Kernel Panic - Memory modified after free (8.0-RELEASE)
Summary: [xen] [panic] Xen Kernel Panic - Memory modified after free (8.0-RELEASE)
Status: Closed FIXED
Alias: None
Product: Base System
Classification: Unclassified
Component: kern (show other bugs)
Version: 8.0-RELEASE
Hardware: Any Any
: Normal Affects Only Me
Assignee: freebsd-xen (Nobody)
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2010-01-21 21:30 UTC by Steve
Modified: 2014-06-05 14:40 UTC (History)
1 user (show)

See Also:

Attachments
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2010-01-21 21:30 UTC, Steve 		no flags Details
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Description Steve 2010-01-21 21:30:04 UTC 
I randomly get kernel panics running FreeBSD 8.0 within a Xen virtual machine. The host is i386.

Here's what was displayed on the console at the time of one such panic:

Memory modified after free 0xc1405000(4092) val=deadc0e9 @ 0xc1405878
panic: Most recently used by subproc

cpuid = 0
KDB: enter: panic
[thread pid 887 tid 100047 ]
Stopped at      kdb_enter+0x3a: movl    $0,kdb_why
db>

My kernel conf file, xen VM conf file, 'xm info' are all attached.

Fix: Patch attached with submission follows:
How-To-Repeat: Occurs randomly
Comment 1 Mark Linimon freebsd_committer freebsd_triage 2010-01-23 00:11:22 UTC 
Responsible Changed
From-To: freebsd-bugs->freebsd-xen

Over to maintainer(s).
Comment 2 Colin Percival freebsd_committer freebsd_triage 2010-12-27 06:08:56 UTC 
Hi Steve,

I've fixed several bugs in the FreeBSD/Xen code over the past couple of
months, including a few which could have caused the corruption you reported
here; can you try with a recent (today's 9-CURRENT, or 8.2-RC1) tree and
let me know if you can still reproduce this?

Thanks,
-- 
Colin Percival
Security Officer, FreeBSD | freebsd.org | The power to serve
Founder / author, Tarsnap | tarsnap.com | Online backups for the truly paranoid
Comment 3 Colin Percival freebsd_committer freebsd_triage 2010-12-28 00:19:42 UTC 
State Changed
From-To: open->feedback

Place into feedback state awaiting confirmation of whether this 
problem still exists.
Comment 4 Roger Pau Monné freebsd_committer freebsd_triage 2014-06-05 14:40:57 UTC 
Closed since no feedback has been received for more than 3 years and Colin Percival fixes probably solved the issue.