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net/tls: Don't recursively call push_record during tls_write_space callbacks

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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>
This commit is contained in:
Dave Watson 2018-05-01 13:05:39 -07:00 committed by David S. Miller
parent edd7ceb782
commit c212d2c7fc
2 changed files with 8 additions and 0 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

1
include/net/tls.h
View file

@ -148,6 +148,7 @@ struct tls_context {
struct scatterlist *partially_sent_record; struct scatterlist *partially_sent_record;
u16 partially_sent_offset; u16 partially_sent_offset;
unsigned long flags; unsigned long flags;
bool in_tcp_sendpages;
u16 pending_open_record_frags; u16 pending_open_record_frags;
int (*push_pending_record)(struct sock *sk, int flags); int (*push_pending_record)(struct sock *sk, int flags);

7
net/tls/tls_main.c
View file

@ -114,6 +114,7 @@ int tls_push_sg(struct sock *sk,
size = sg->length - offset; size = sg->length - offset;
offset += sg->offset; offset += sg->offset;
ctx->in_tcp_sendpages = true;
while (1) { while (1) {
if (sg_is_last(sg)) if (sg_is_last(sg))
sendpage_flags = flags; sendpage_flags = flags;
@ -148,6 +149,8 @@ int tls_push_sg(struct sock *sk,
} }
clear_bit(TLS_PENDING_CLOSED_RECORD, &ctx->flags); clear_bit(TLS_PENDING_CLOSED_RECORD, &ctx->flags);
ctx->in_tcp_sendpages = false;
ctx->sk_write_space(sk);
return 0; return 0;
} }
@ -217,6 +220,10 @@ static void tls_write_space(struct sock *sk)
{ {
struct tls_context *ctx = tls_get_ctx(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)) { if (!sk->sk_write_pending && tls_is_pending_closed_record(ctx)) {
gfp_t sk_allocation = sk->sk_allocation; gfp_t sk_allocation = sk->sk_allocation;
int rc; int rc;