Looks like this patch got lost, do you need me to resend?
I should also have added a stable cc and a
Fixes: 95ad37f90c33 "NFSv4.2: add client side xattr caching."
--b.
On Wed, Oct 21, 2020 at 10:34:15AM -0400, bfields wrote:
> From: "J. Bruce Fields" <bfields@xxxxxxxxxx>
>
> We forgot to unregister the nfs4_xattr_large_entry_shrinker.
>
> That leaves the global list of shrinkers corrupted after unload of the
> nfs module, after which possibly unrelated code that calls
> register_shrinker() or unregister_shrinker() gets a BUG() with
> "supervisor write access in kernel mode".
>
> And similarly for the nfs4_xattr_large_entry_lru.
>
> Reported-by: Kris Karas <bugs-a17@xxxxxxxxxxxxxxxx>
> Tested-By: Kris Karas <bugs-a17@xxxxxxxxxxxxxxxx>
> Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
> ---
> fs/nfs/nfs42xattr.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/fs/nfs/nfs42xattr.c b/fs/nfs/nfs42xattr.c
> index 86777996cfec..55b44a42d625 100644
> --- a/fs/nfs/nfs42xattr.c
> +++ b/fs/nfs/nfs42xattr.c
> @@ -1048,8 +1048,10 @@ int __init nfs4_xattr_cache_init(void)
>
> void nfs4_xattr_cache_exit(void)
> {
> + unregister_shrinker(&nfs4_xattr_large_entry_shrinker);
> unregister_shrinker(&nfs4_xattr_entry_shrinker);
> unregister_shrinker(&nfs4_xattr_cache_shrinker);
> + list_lru_destroy(&nfs4_xattr_large_entry_lru);
> list_lru_destroy(&nfs4_xattr_entry_lru);
> list_lru_destroy(&nfs4_xattr_cache_lru);
> kmem_cache_destroy(nfs4_xattr_cache_cachep);
> --
> 2.26.2
>
