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From: David Miller <davem@davemloft.net>
To: edumazet@google.com
Cc: netdev@vger.kernel.org, soheil@google.com, ncardwell@google.com,
	eric.dumazet@gmail.com, jbaron@akamai.com, rutsky@google.com
Subject: Re: [PATCH net] tcp: remove empty skb from write queue in error cases
Date: Tue, 27 Aug 2019 21:38:05 -0700 (PDT)	[thread overview]
Message-ID: <20190827.213805.294784850249692598.davem@davemloft.net> (raw)
In-Reply-To: <20190826161915.81676-1-edumazet@google.com>

From: Eric Dumazet <edumazet@google.com>
Date: Mon, 26 Aug 2019 09:19:15 -0700

> Vladimir Rutsky reported stuck TCP sessions after memory pressure
> events. Edge Trigger epoll() user would never receive an EPOLLOUT
> notification allowing them to retry a sendmsg().
> 
> Jason tested the case of sk_stream_alloc_skb() returning NULL,
> but there are other paths that could lead both sendmsg() and sendpage()
> to return -1 (EAGAIN), with an empty skb queued on the write queue.
> 
> This patch makes sure we remove this empty skb so that
> Jason code can detect that the queue is empty, and
> call sk->sk_write_space(sk) accordingly.
> 
> Fixes: ce5ec440994b ("tcp: ensure epoll edge trigger wakeup when write queue is empty")
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Cc: Jason Baron <jbaron@akamai.com>
> Reported-by: Vladimir Rutsky <rutsky@google.com>

Applied and queued up for -stable.

  parent reply	other threads:[~2019-08-28  4:38 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-26 16:19 [PATCH net] tcp: remove empty skb from write queue in error cases Eric Dumazet
2019-08-26 16:50 ` Soheil Hassas Yeganeh
2019-08-26 17:18 ` Neal Cardwell
2019-08-26 19:56 ` Jason Baron
2019-08-26 20:04   ` Eric Dumazet
2019-08-28  4:38 ` David Miller [this message]
2019-09-11 17:36 ` Christoph Paasch
2019-09-11 20:59   ` Eric Dumazet

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