FAILED: patch "[PATCH] fscrypt: destroy keyring after security_sb_delete()" failed to apply to 5.10-stable tree

The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x ccb820dc7d2236b1af0d54ae038a27b5b6d5ae5a
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '[email protected]' --subject-prefix 'PATCH 5.10.y' HEAD^..

Possible dependencies:

ccb820dc7d22 ("fscrypt: destroy keyring after security_sb_delete()") 83e804f0bfee ("fs,security: Add sb_delete hook")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From ccb820dc7d2236b1af0d54ae038a27b5b6d5ae5a Mon Sep 17 00:00:00 2001
From: Eric Biggers <[email protected]>
Date: Mon, 13 Mar 2023 15:12:29 -0700
Subject: [PATCH] fscrypt: destroy keyring after security_sb_delete()

fscrypt_destroy_keyring() must be called after all potentially-encrypted inodes were evicted; otherwise it cannot safely destroy the keyring. Since inodes that are in-use by the Landlock LSM don't get evicted until security_sb_delete(), this means that fscrypt_destroy_keyring() must be called *after* security_sb_delete().

This fixes a WARN_ON followed by a NULL dereference, only possible if Landlock was being used on encrypted files.

index 84332d5cb817..04bc62ab7dfe 100644
@@ -475,13 +475,22 @@ void generic_shutdown_super(struct super_block *sb)
 
 		cgroup_writeback_umount();
 
-		/* evict all inodes with zero refcount */
+		/* Evict all inodes with zero refcount. */
 		evict_inodes(sb);
-		/* only nonzero refcount inodes can have marks */
+
+		/*
+		 * Clean up and evict any inodes that still have references due
+		 * to fsnotify or the security policy.
+		 */
 		fsnotify_sb_delete(sb);
-		fscrypt_destroy_keyring(sb);
 		security_sb_delete(sb);
 
+		/*
+		 * Now that all potentially-encrypted inodes have been evicted,
+		 * the fscrypt keyring can be destroyed.
+		 */
+		fscrypt_destroy_keyring(sb);
+
 		if (sb->s_dio_done_wq) {
 			destroy_workqueue(sb->s_dio_done_wq);
 			sb->s_dio_done_wq = NULL;