linux-kernel - [PATCH] fscrypt: clear keyring before calling key

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Date: Tue,  6 Feb 2024 10:16:19 +0000
From: Luis Henriques <lhenriques@...e.de>
To: Eric Biggers <ebiggers@...nel.org>,
	"Theodore Y. Ts'o" <tytso@....edu>,
	Jaegeuk Kim <jaegeuk@...nel.org>
Cc: David Howells <dhowells@...hat.com>,
	Jarkko Sakkinen <jarkko@...nel.org>,
	linux-fscrypt@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Luis Henriques <lhenriques@...e.de>
Subject: [PATCH] fscrypt: clear keyring before calling key_put()

Now that the key quotas are handled immediately on key_put() instead of
being postponed to the key management garbage collection worker, a call to
keyring_clear() is all that is required in fscrypt_put_master_key() so that
the keyring clean-up is also done synchronously.  This patch should fix the
fstest generic/581 flakiness.

Signed-off-by: Luis Henriques <lhenriques@...e.de>
---
Hi!

I know that patch "keys: update key quotas in key_put()" isn't yet merged
but since David and Jarkko seem to be OK with it, it doesn't hurt to send
this follow-up patch immediately.

Cheers,
-- 
Luis

 fs/crypto/keyring.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/fs/crypto/keyring.c b/fs/crypto/keyring.c
index 0edf0b58daa7..dfdaae16b83a 100644
--- a/fs/crypto/keyring.c
+++ b/fs/crypto/keyring.c
@@ -74,8 +74,11 @@ void fscrypt_put_master_key(struct fscrypt_master_key *mk)
 	 * that concurrent keyring lookups can no longer find it.
 	 */
 	WARN_ON_ONCE(refcount_read(&mk->mk_active_refs) != 0);
-	key_put(mk->mk_users);
-	mk->mk_users = NULL;
+	if (mk->mk_users) {
+		keyring_clear(mk->mk_users);
+		key_put(mk->mk_users);
+		mk->mk_users = NULL;
+	}
 	call_rcu(&mk->mk_rcu_head, fscrypt_free_master_key);
 }