This is a note to let you know that I've just added the patch titled
NFSv4.2: fix failure to unregister shrinker
to the 5.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nfsv4.2-fix-failure-to-unregister-shrinker.patch
and it can be found in the queue-5.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 70438afbf17e5194dd607dd17759560a363b7bb4 Mon Sep 17 00:00:00 2001
From: "J. Bruce Fields" <bfields@xxxxxxxxxx>
Date: Wed, 21 Oct 2020 10:34:15 -0400
Subject: NFSv4.2: fix failure to unregister shrinker
From: J. Bruce Fields <bfields@xxxxxxxxxx>
commit 70438afbf17e5194dd607dd17759560a363b7bb4 upstream.
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>
Fixes: 95ad37f90c33 "NFSv4.2: add client side xattr caching."
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
CC: stable@xxxxxxxxxxxxxxx
Signed-off-by: Anna Schumaker <Anna.Schumaker@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/nfs/nfs42xattr.c | 2 ++
1 file changed, 2 insertions(+)
--- a/fs/nfs/nfs42xattr.c
+++ b/fs/nfs/nfs42xattr.c
@@ -1048,8 +1048,10 @@ 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);
Patches currently in stable-queue which might be from bfields@xxxxxxxxxx are
queue-5.9/nfsv4.2-fix-failure-to-unregister-shrinker.patch
queue-5.9/nfsd-fix-use-after-free-warning-when-doing-inter-ser.patch
queue-5.9/sunrpc-fix-general-protection-fault-in-trace_rpc_xdr.patch
queue-5.9/nfsd-fix-missing-refcount-in-nfsd4_copy-by-nfsd4_do_.patch
