This is a note to let you know that I've just added the patch titled
net, sk_msg: Don't check if sock is locked when tearing down psock
to the 5.4-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:
net-sk_msg-don-t-check-if-sock-is-locked-when-tearing-down-psock.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 58c8db929db1c1d785a6f5d8f8692e5dbcc35e84 Mon Sep 17 00:00:00 2001
From: Jakub Sitnicki <jakub@xxxxxxxxxxxxxx>
Date: Tue, 21 Jan 2020 13:31:47 +0100
Subject: net, sk_msg: Don't check if sock is locked when tearing down psock
From: Jakub Sitnicki <jakub@xxxxxxxxxxxxxx>
commit 58c8db929db1c1d785a6f5d8f8692e5dbcc35e84 upstream.
As John Fastabend reports [0], psock state tear-down can happen on receive
path *after* unlocking the socket, if the only other psock user, that is
sockmap or sockhash, releases its psock reference before tcp_bpf_recvmsg
does so:
tcp_bpf_recvmsg()
psock = sk_psock_get(sk) <- refcnt 2
lock_sock(sk);
...
sock_map_free() <- refcnt 1
release_sock(sk)
sk_psock_put() <- refcnt 0
Remove the lockdep check for socket lock in psock tear-down that got
introduced in 7e81a3530206 ("bpf: Sockmap, ensure sock lock held during
tear down").
[0] https://lore.kernel.org/netdev/5e25dc995d7d_74082aaee6e465b441@john-XPS-13-9370.notmuch/
Fixes: 7e81a3530206 ("bpf: Sockmap, ensure sock lock held during tear down")
Reported-by: syzbot+d73682fcf7fee6982fe3@xxxxxxxxxxxxxxxxxxxxxxxxx
Suggested-by: John Fastabend <john.fastabend@xxxxxxxxx>
Signed-off-by: Jakub Sitnicki <jakub@xxxxxxxxxxxxxx>
Acked-by: John Fastabend <john.fastabend@xxxxxxxxx>
Acked-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/core/skmsg.c | 2 --
1 file changed, 2 deletions(-)
--- a/net/core/skmsg.c
+++ b/net/core/skmsg.c
@@ -594,8 +594,6 @@ EXPORT_SYMBOL_GPL(sk_psock_destroy);
void sk_psock_drop(struct sock *sk, struct sk_psock *psock)
{
- sock_owned_by_me(sk);
-
sk_psock_cork_free(psock);
sk_psock_zap_ingress(psock);
Patches currently in stable-queue which might be from jakub@xxxxxxxxxxxxxx are
queue-5.4/net-sk_msg-don-t-check-if-sock-is-locked-when-tearing-down-psock.patch
