APPLIED: [SRU][N][PATCH 0/1] nfsd: initialise nfsd_info.mutex early (LP: 2070358)

[Stefan Bader]

On 12.07.24 20:42, patricia.domingues at canonical.com wrote:
> BugLink: https://bugs.launchpad.net/bugs/2070358
> 
> SRU Justification:
> 
> [Impact]
>   * When the sosreport command is executed, a kernel OOPS happens and the system is crashing,
>    depending on the configuration (but default) the system/LPAR is rebooting.
>   
> [Fix]
>   * e0011bca603c101f2a3c007bdb77f7006fa78fb1 e0011bca603c "nfsd: initialise nfsd_info.mutex early"
>   
> [Test Case]
>   * Have a Ubuntu Server 24.04 LTS installation on ppc64el.
>   * one option is only running sosreport on the system - and
>   the crash is seen when the sosreport is starting to capture dump
>   * second option (without sosreport) is:
>   * CONFIG_NFSD=m (or y) must be set
>   * mount nfsd if not already, using "$ mount -t nfsd nfsd /proc/fs/nfsd" command
>   * The kernel oops will happen and the logs will show:
>     ...
>     BUG: Kernel NULL pointer dereference on read at 0x00000000
>     Faulting instruction address: 0xc0000000016ff114
>     Oops: Kernel access of bad area, sig: 11 [#1]
>     ...
>   * On a system with that kernel that incl. the above patch
>     no oops will occur and the sosreport command will execute normally.
>   
> [Regression Potential]
> * There is a certain risk of a regression, with any code modification,
>    and here because the mutex handling in nfsd is modified.
>   
> * But the changes are pretty traceable.
>   
> * On top the commit is already upstream reviewed and accepted.
>   
> * The modifications were done by the NFSD maintainer and also tested by IBM.
>   
> [Other]
> * The fix/commit got upstream accepted with kernel v6.10-rc7,
>    hence Oracular is not affected.
> 
> 
> NeilBrown (1):
>    nfsd: initialise nfsd_info.mutex early.
> 
>   fs/nfsd/nfsctl.c | 2 ++
>   fs/nfsd/nfssvc.c | 1 -
>   2 files changed, 2 insertions(+), 1 deletion(-)
> 

Applied to noble:linux/master-next. Thanks.

-Stefan

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