Bug 209845 - ignore_msrs kernel NULL pointer dereference since 12bc2132b15e0a969b3f455d90a5f215ef239eff
Summary: ignore_msrs kernel NULL pointer dereference since 12bc2132b15e0a969b3f455d90a...
Status: NEW
Alias: None
Product: Virtualization
Classification: Unclassified
Component: kvm (show other bugs)
Hardware: x86-64 Linux
: P1 normal
Assignee: virtualization_kvm
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2020-10-25 11:28 UTC by Steffen Dirkwinkel
Modified: 2020-10-25 16:24 UTC (History)
0 users

See Also:
Kernel Version: 5.9
Subsystem:
Regression: Yes
Bisected commit-id:

Attachments
dmesg section (4.85 KB, text/plain)
2020-10-25 11:28 UTC, Steffen Dirkwinkel 		Details
Add an attachment (proposed patch, testcase, etc.)

Description Steffen Dirkwinkel 2020-10-25 11:28:21 UTC 
Created attachment 293183 [details]
dmesg section

Since commit 12bc2132b15e0a969b3f455d90a5f215ef239eff kvm crashes with a null pointer dereference when ignore_msrs is set (log in attachement) 

Hardware: AMD Ryzen 3700x


other reports:
- https://www.reddit.com/r/VFIO/comments/jdh9pp/so_i_just_updated_to_kernel_591_and/ 


- https://forum.manjaro.org/t/kernel-5-9-no-virtualization/31562
Comment 1 peterx 2020-10-25 16:24:27 UTC 
On Sun, Oct 25, 2020 at 11:28:21AM +0000, bugzilla-daemon@bugzilla.kernel.org wrote:
> https://bugzilla.kernel.org/show_bug.cgi?id=209845
> 
>             Bug ID: 209845
>            Summary: ignore_msrs kernel NULL pointer dereference since
>                     12bc2132b15e0a969b3f455d90a5f215ef239eff
>            Product: Virtualization
>            Version: unspecified
>     Kernel Version: 5.9
>           Hardware: x86-64
>                 OS: Linux
>               Tree: Mainline
>             Status: NEW
>           Severity: normal
>           Priority: P1
>          Component: kvm
>           Assignee: virtualization_kvm@kernel-bugs.osdl.org
>           Reporter: kernel-bugs@steffen.cc
>         Regression: No
> 
> Created attachment 293183 [details]
>   --> https://bugzilla.kernel.org/attachment.cgi?id=293183&action=edit
> dmesg section
> 
> Since commit 12bc2132b15e0a969b3f455d90a5f215ef239eff kvm crashes with a null
> pointer dereference when ignore_msrs is set (log in attachement) 
> 
> Hardware: AMD Ryzen 3700x

kvm_msr_ignored_check() should consider vcpu null case for kvm vm get msr
features..  I'll post a fix soon, probably with a selftest too.  Thanks,
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