linux-kernel - [Bisected][-next-20130204+] [x86/kvm] udevd:[97]: segfault at ffffffffff5fd020 ip 00007fff069e277f sp 00007fff068c9ef8 error d

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Date:	Tue, 12 Feb 2013 19:26:50 -0500
From:	Peter Hurley <peter@...leysoftware.com>
To:	"H. Peter Anvin" <hpa@...ux.intel.com>
Cc:	linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Subject: [Bisected][-next-20130204+] [x86/kvm] udevd:[97]: segfault at
 ffffffffff5fd020 ip 00007fff069e277f sp 00007fff068c9ef8 error d

With -next-20130204+ in ubuntu 12.10 VM (so the 80x25 VGA
device/console):

[    0.666410] udevd[97]: starting version 175
[    0.674043] udevd[97]: udevd:[97]: segfault at ffffffffff5fd020 ip 00007fff069e277f sp 00007fff068c9ef8 error d

and boots to an initramfs prompt.

git bisect (log attached) blames:

commit 7b5c4a65cc27f017c170b025f8d6d75dabb11c6f
Merge: 3596f5b 949db15
Author: H. Peter Anvin <hpa@...ux.intel.com>
Date:   Fri Jan 25 16:31:21 2013 -0800

    Merge tag 'v3.8-rc5' into x86/mm
    
    The __pa() fixup series that follows touches KVM code that is not
    present in the existing branch based on v3.7-rc5, so merge in the
    current upstream from Linus.
    
    Signed-off-by: H. Peter Anvin <hpa@...ux.intel.com>


This only happens with the VGA device/console but that is the default
configuration for Ubuntu/KVM because it blacklists pretty much every fb
driver.

I can confirm this _does not_ happen with same config on mainline
3.8-rc7.
Just confirmed that the same fault occurs with next-20130211.

Regards,
Peter Hurley

View attachment "segfault_bisect.log" of type "text/x-log" (4228 bytes)