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authorDave Watson <davejwatson@fb.com>2018-05-01 13:05:39 -0700
committerDavid S. Miller <davem@davemloft.net>2018-05-01 18:57:52 -0400
commitc212d2c7fc4736d49be102fb7a1a545cdc2f1fea (patch)
treef4ebbd4af00a32f8f96ea2d92498c533d33da615 /net/tls
parentedd7ceb78296fb1574958991b6655c3c2cedf124 (diff)
downloadlinux-c212d2c7fc4736d49be102fb7a1a545cdc2f1fea.tar.gz
net/tls: Don't recursively call push_record during tls_write_space callbacks
It is reported that in some cases, write_space may be called in
do_tcp_sendpages, such that we recursively invoke do_tcp_sendpages again:

[  660.468802]  ? do_tcp_sendpages+0x8d/0x580
[  660.468826]  ? tls_push_sg+0x74/0x130 [tls]
[  660.468852]  ? tls_push_record+0x24a/0x390 [tls]
[  660.468880]  ? tls_write_space+0x6a/0x80 [tls]
...

tls_push_sg already does a loop over all sending sg's, so ignore
any tls_write_space notifications until we are done sending.
We then have to call the previous write_space to wake up
poll() waiters after we are done with the send loop.

Reported-by: Andre Tomt <andre@tomt.net>
Signed-off-by: Dave Watson <davejwatson@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/tls')
-rw-r--r--net/tls/tls_main.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/net/tls/tls_main.c b/net/tls/tls_main.c
index 0d379970960e..cc03e00785c7 100644
--- a/net/tls/tls_main.c
+++ b/net/tls/tls_main.c
@@ -114,6 +114,7 @@ int tls_push_sg(struct sock *sk,
 	size = sg->length - offset;
 	offset += sg->offset;
 
+	ctx->in_tcp_sendpages = true;
 	while (1) {
 		if (sg_is_last(sg))
 			sendpage_flags = flags;
@@ -148,6 +149,8 @@ retry:
 	}
 
 	clear_bit(TLS_PENDING_CLOSED_RECORD, &ctx->flags);
+	ctx->in_tcp_sendpages = false;
+	ctx->sk_write_space(sk);
 
 	return 0;
 }
@@ -217,6 +220,10 @@ static void tls_write_space(struct sock *sk)
 {
 	struct tls_context *ctx = tls_get_ctx(sk);
 
+	/* We are already sending pages, ignore notification */
+	if (ctx->in_tcp_sendpages)
+		return;
+
 	if (!sk->sk_write_pending && tls_is_pending_closed_record(ctx)) {
 		gfp_t sk_allocation = sk->sk_allocation;
 		int rc;