From: bfields@fieldses.org (J. Bruce Fields)
To: Trond Myklebust <trondmy@hammerspace.com>,
Anna Schumaker <schumakeranna@gmail.com>
Cc: linux-nfs@vger.kernel.org
Subject: [PATCH] NFSv4.2: fix failure to unregister shrinker
Date: Wed, 21 Oct 2020 10:34:15 -0400 [thread overview]
Message-ID: <20201021143415.GA27122@fieldses.org> (raw)
From: "J. Bruce Fields" <bfields@redhat.com>
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>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
---
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
next reply other threads:[~2020-10-21 14:34 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-21 14:34 J. Bruce Fields [this message]
2020-11-12 14:03 ` [PATCH] NFSv4.2: fix failure to unregister shrinker J. Bruce Fields
2020-11-12 14:07 ` Anna Schumaker
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