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Bug 486040 - sys-kernel/hardened-sources-3.11.1-r1 - PAX: refcount overflow detected
Summary: sys-kernel/hardened-sources-3.11.1-r1 - PAX: refcount overflow detected
Status: RESOLVED FIXED
Alias: None
Product: Gentoo Linux
Classification: Unclassified
Component: Hardened (show other bugs)
Hardware: All Linux
: Normal normal
Assignee: The Gentoo Linux Hardened Team
URL:
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2013-09-25 21:39 UTC by Alexander Tsoy
Modified: 2013-09-30 12:05 UTC (History)
2 users (show)

See Also:
Package list:
Runtime testing required: ---

Attachments
screenshot (screen1.png,115.04 KB, image/png)
2013-09-25 21:39 UTC, Alexander Tsoy 		Details
console.log (serial-console.log,63.80 KB, text/plain)
2013-09-26 12:13 UTC, Alexander Tsoy 		Details
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Description Alexander Tsoy 2013-09-25 21:39:28 UTC 
Created attachment 359476 [details]
screenshot

Kernel panic in KVM guest. Seems it happen in the initramfs stage. I can't get output from the serial console, so here is a screenshot.
Comment 1 Alexander Tsoy 2013-09-25 22:31:47 UTC 
Initramfs generated by dracut and utilize systemd as init. No problems on my two physical machines (but with different kernel config). I'll try to reproduce this panic in KVM guest on my local system, where I able to get the full console output.
Comment 2 Alexander Tsoy 2013-09-26 12:13:10 UTC 
Created attachment 359512 [details]
console.log
Comment 3 Alexander Tsoy 2013-09-26 16:13:46 UTC 
(In reply to Alexander Tsoy from comment #1)
> No problems on my two physical machines (but with different kernel config)

CONFIG_PAX_REFCOUNT is enabled on theese machines, but I can reproduce this problem only in KVM guests.
Comment 4 Anthony Basile gentoo-dev 2013-09-26 19:02:24 UTC 
(In reply to Alexander Tsoy from comment #3)
> (In reply to Alexander Tsoy from comment #1)
> > No problems on my two physical machines (but with different kernel config)
> 
> CONFIG_PAX_REFCOUNT is enabled on theese machines, but I can reproduce this
> problem only in KVM guests.

I've heard some other reports of problems in kvm.  I'm passing this upstream.
Comment 5 PaX Team 2013-09-26 19:59:39 UTC 
this percpu refcount code looks pretty dumb that manages to trigger signed overflows left and right due to:

#define PCPU_COUNT_BIAS (1U << 31)

i'll see what i can do about it.
Comment 6 PaX Team 2013-09-26 23:55:07 UTC 
should be fixed in the latest patch.
Comment 7 Alexander Tsoy 2013-09-30 07:42:33 UTC 
Fixed in hardened-sources-3.11.2
Comment 8 Anthony Basile gentoo-dev 2013-09-30 12:05:35 UTC 
(In reply to Alexander Tsoy from comment #7)
> Fixed in hardened-sources-3.11.2

thanks, i'll make it the next stabilization candidate