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From:   Sascha Hauer <s.hauer@pengutronix.de>
To:     netdev@vger.kernel.org
Cc:     linux-kernel@vger.kernel.org,
        "David S . Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, Jens Axboe <axboe@kernel.dk>,
        kernel@pengutronix.de, Sascha Hauer <s.hauer@pengutronix.de>
Subject: [PATCH] net: Do not break out of sk_stream_wait_memory() with TIF_NOTIFY_SIGNAL
Date:   Mon, 23 Oct 2023 14:13:46 +0200
Message-Id: <20231023121346.4098160-1-s.hauer@pengutronix.de>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

It can happen that a socket sends the remaining data at close() time.
With io_uring and KTLS it can happen that sk_stream_wait_memory() bails
out with -512 (-ERESTARTSYS) because TIF_NOTIFY_SIGNAL is set for the
current task. This flag has been set in io_req_normal_work_add() by
calling task_work_add().

It seems signal_pending() is too broad, so this patch replaces it with
task_sigpending(), thus ignoring the TIF_NOTIFY_SIGNAL flag.

A discussion of this issue can be found at
https://lore.kernel.org/20231010141932.GD3114228@pengutronix.de

Suggested-by: Jens Axboe <axboe@kernel.dk>
Fixes: 12db8b690010c ("entry: Add support for TIF_NOTIFY_SIGNAL")
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 net/core/stream.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/core/stream.c b/net/core/stream.c
index 96fbcb9bbb30a..e9e17b48e0122 100644
--- a/net/core/stream.c
+++ b/net/core/stream.c
@@ -67,7 +67,7 @@ int sk_stream_wait_connect(struct sock *sk, long *timeo_p)
 			return -EPIPE;
 		if (!*timeo_p)
 			return -EAGAIN;
-		if (signal_pending(tsk))
+		if (task_sigpending(tsk))
 			return sock_intr_errno(*timeo_p);
 
 		add_wait_queue(sk_sleep(sk), &wait);
@@ -103,7 +103,7 @@ void sk_stream_wait_close(struct sock *sk, long timeout)
 		do {
 			if (sk_wait_event(sk, &timeout, !sk_stream_closing(sk), &wait))
 				break;
-		} while (!signal_pending(current) && timeout);
+		} while (!task_sigpending(current) && timeout);
 
 		remove_wait_queue(sk_sleep(sk), &wait);
 	}
@@ -134,7 +134,7 @@ int sk_stream_wait_memory(struct sock *sk, long *timeo_p)
 			goto do_error;
 		if (!*timeo_p)
 			goto do_eagain;
-		if (signal_pending(current))
+		if (task_sigpending(current))
 			goto do_interrupted;
 		sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
 		if (sk_stream_memory_free(sk) && !vm_wait)
-- 
2.39.2