Commit 70438afb authored Oct 21, 2020 by J. Bruce Fields Committed by Anna Schumaker Nov 12, 2020

NFSv4.2: fix failure to unregister shrinker



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@moonlit-rail.com>
Tested-By: Kris Karas <bugs-a17@moonlit-rail.com>
Fixes: 95ad37f9 "NFSv4.2: add client side xattr caching."
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
CC: stable@vger.kernel.org
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

parent 3fc2bfa3

fs/nfs/nfs42xattr.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -1047,8 +1047,10 @@ out4:

		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);

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