linux-kernel - [PATCH] afs: Use kfree_rcu() instead of casting kfree() to rcu_callback

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-Id: <20200306161718.50702-1-jannh@google.com>
Date:   Fri,  6 Mar 2020 17:17:18 +0100
From:   Jann Horn <jannh@...gle.com>
To:     David Howells <dhowells@...hat.com>
Cc:     linux-afs@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH] afs: Use kfree_rcu() instead of casting kfree() to rcu_callback_t

afs_put_addrlist() casts kfree() to rcu_callback_t. Apart from being wrong
in theory, this might also blow up when people start enforcing function
types via compiler instrumentation, and it means the rcu_head has to be
first in struct afs_addr_list.

Use kfree_rcu() instead, it's simpler and more correct.

Signed-off-by: Jann Horn <jannh@...gle.com>
---
compile-tested only

 fs/afs/addr_list.c | 2 +-
 fs/afs/internal.h  | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/afs/addr_list.c b/fs/afs/addr_list.c
index df415c05939e..de1ae0bead3b 100644
--- a/fs/afs/addr_list.c
+++ b/fs/afs/addr_list.c
@@ -19,7 +19,7 @@
 void afs_put_addrlist(struct afs_addr_list *alist)
 {
 	if (alist && refcount_dec_and_test(&alist->usage))
-		call_rcu(&alist->rcu, (rcu_callback_t)kfree);
+		kfree_rcu(alist, rcu);
 }
 
 /*
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index 1d81fc4c3058..35f951ac296f 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -81,7 +81,7 @@ enum afs_call_state {
  * List of server addresses.
  */
 struct afs_addr_list {
-	struct rcu_head		rcu;		/* Must be first */
+	struct rcu_head		rcu;
 	refcount_t		usage;
 	u32			version;	/* Version */
 	unsigned char		max_addrs;

base-commit: aeb542a1b5c507ea117d21c3e3e012ba16f065ac
-- 
2.25.0.265.gbab2e86ba0-goog