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authorTom Herbert <tom@herbertland.com>2016-08-23 11:55:31 -0700
committerDavid S. Miller <davem@davemloft.net>2016-08-23 16:23:12 -0700
commit1616b38f201945f5fc88aa09b525e3625777aa7c (patch)
tree0d5f890a7b0d21fa7c4d7580a70e0bfcae2c0738 /net/kcm/kcmsock.c
parentcff6a334e63420e95ec40dc7fcdc0b8258615760 (diff)
downloadlinux-1616b38f201945f5fc88aa09b525e3625777aa7c.tar.gz
kcm: Fix locking issue
Lock the lower socket in kcm_unattach. Release during call to strp_done
since that function cancels the RX timers and work queue with sync.

Also added some status information in psock reporting.

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/kcm/kcmsock.c')
-rw-r--r--net/kcm/kcmsock.c13
1 files changed, 8 insertions, 5 deletions
diff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c
index eedbe404af35..eb731cacc325 100644
--- a/net/kcm/kcmsock.c
+++ b/net/kcm/kcmsock.c
@@ -1477,12 +1477,13 @@ out:
 	return err;
 }
 
-/* Lower socket lock held */
 static void kcm_unattach(struct kcm_psock *psock)
 {
 	struct sock *csk = psock->sk;
 	struct kcm_mux *mux = psock->mux;
 
+	lock_sock(csk);
+
 	/* Stop getting callbacks from TCP socket. After this there should
 	 * be no way to reserve a kcm for this psock.
 	 */
@@ -1514,7 +1515,10 @@ static void kcm_unattach(struct kcm_psock *psock)
 
 	write_unlock_bh(&csk->sk_callback_lock);
 
+	/* Call strp_done without sock lock */
+	release_sock(csk);
 	strp_done(&psock->strp);
+	lock_sock(csk);
 
 	bpf_prog_put(psock->bpf_prog);
 
@@ -1564,6 +1568,8 @@ no_reserved:
 		fput(csk->sk_socket->file);
 		kmem_cache_free(kcm_psockp, psock);
 	}
+
+	release_sock(csk);
 }
 
 static int kcm_unattach_ioctl(struct socket *sock, struct kcm_unattach *info)
@@ -1749,11 +1755,8 @@ static void release_mux(struct kcm_mux *mux)
 	/* Release psocks */
 	list_for_each_entry_safe(psock, tmp_psock,
 				 &mux->psocks, psock_list) {
-		if (!WARN_ON(psock->unattaching)) {
-			lock_sock(psock->strp.sk);
+		if (!WARN_ON(psock->unattaching))
 			kcm_unattach(psock);
-			release_sock(psock->strp.sk);
-		}
 	}
 
 	if (WARN_ON(mux->psocks_cnt))