linux-kernel - [PATCH -mm 2/3] nbd: nbd_thread_recv: remove the buggy kernel_dequeue

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Date:	Sun, 25 Oct 2015 16:26:39 +0100
From:	Oleg Nesterov <oleg@...hat.com>
To:	Andrew Morton <akpm@...ux-foundation.org>,
	Markus Pargmann <mpa@...gutronix.de>
Cc:	nbd-general@...ts.sourceforge.net, linux-kernel@...r.kernel.org
Subject: [PATCH -mm 2/3] nbd: nbd_thread_recv: remove the buggy
	kernel_dequeue_signal()

nbd_thread_recv() is called by userspace, it is very wrong to dequeue
and throw out a signal.

I do not understand why nbd_thread_recv() (and nbd_thread_send() btw)
does sock_shutdown(); the caller, __nbd_ioctl(NBD_DO_IT) does this too.

Signed-off-by: Oleg Nesterov <oleg@...hat.com>
---
 drivers/block/nbd.c |    5 ++---
 1 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index e5d96e5..0ffd73c 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -444,9 +444,8 @@ static int nbd_thread_recv(struct nbd_device *nbd)
 	spin_unlock_irqrestore(&nbd->tasks_lock, flags);
 
 	if (signal_pending(current)) {
-		ret = kernel_dequeue_signal(NULL);
-		dev_warn(nbd_to_dev(nbd), "pid %d, %s, got signal %d\n",
-			 task_pid_nr(current), current->comm, ret);
+		dev_warn(nbd_to_dev(nbd), "pid %d, %s, got signal",
+			 task_pid_nr(current), current->comm);
 		mutex_lock(&nbd->tx_lock);
 		sock_shutdown(nbd);
 		mutex_unlock(&nbd->tx_lock);
-- 
1.5.5.1

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