From 1616b38f201945f5fc88aa09b525e3625777aa7c Mon Sep 17 00:00:00 2001
From: Tom Herbert <tom@herbertland.com>
Date: Tue, 23 Aug 2016 11:55:31 -0700
Subject: 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>
---
net/kcm/kcmsock.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
(limited to 'net/kcm/kcmsock.c')
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))
--
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