From: Dave Watson Date: Tue, 1 May 2018 20:05:39 +0000 (-0700) Subject: net/tls: Don't recursively call push_record during tls_write_space callbacks X-Git-Tag: v4.17-rc4~23^2~20 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=c212d2c7fc4736d49be102fb7a1a545cdc2f1fea;p=linux.git 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 Signed-off-by: Dave Watson Signed-off-by: David S. Miller --- diff --git a/include/net/tls.h b/include/net/tls.h index 3da8e13a6d96..b400d0bb7448 100644 --- a/include/net/tls.h +++ b/include/net/tls.h @@ -148,6 +148,7 @@ struct tls_context { struct scatterlist *partially_sent_record; u16 partially_sent_offset; unsigned long flags; + bool in_tcp_sendpages; u16 pending_open_record_frags; int (*push_pending_record)(struct sock *sk, int flags); 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 @@ int tls_push_sg(struct sock *sk, } 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;