The patch below does not apply to the 4.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 9523feac272ccad2ad8186ba4fcc89103754de52 Mon Sep 17 00:00:00 2001
From: Tuomas Tynkkynen tuomas@tuxera.com Date: Wed, 6 Sep 2017 17:59:08 +0300 Subject: [PATCH] net/9p: Switch to wait_event_killable()
Because userspace gets Very Unhappy when calls like stat() and execve() return -EINTR on 9p filesystem mounts. For instance, when bash is looking in PATH for things to execute and some SIGCHLD interrupts stat(), bash can throw a spurious 'command not found' since it doesn't retry the stat().
In practice, hitting the problem is rare and needs a really slow/bogged down 9p server.
Cc: stable@vger.kernel.org Signed-off-by: Tuomas Tynkkynen tuomas@tuxera.com Signed-off-by: Al Viro viro@zeniv.linux.org.uk
diff --git a/net/9p/client.c b/net/9p/client.c index 4674235b0d9b..1beb131dd3e1 100644 --- a/net/9p/client.c +++ b/net/9p/client.c @@ -773,8 +773,7 @@ p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...) } again: /* Wait for the response */ - err = wait_event_interruptible(*req->wq, - req->status >= REQ_STATUS_RCVD); + err = wait_event_killable(*req->wq, req->status >= REQ_STATUS_RCVD);
/* * Make sure our req is coherent with regard to updates in other diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c index f24b25c25106..f3a4efcf1456 100644 --- a/net/9p/trans_virtio.c +++ b/net/9p/trans_virtio.c @@ -286,8 +286,8 @@ p9_virtio_request(struct p9_client *client, struct p9_req_t *req) if (err == -ENOSPC) { chan->ring_bufs_avail = 0; spin_unlock_irqrestore(&chan->lock, flags); - err = wait_event_interruptible(*chan->vc_wq, - chan->ring_bufs_avail); + err = wait_event_killable(*chan->vc_wq, + chan->ring_bufs_avail); if (err == -ERESTARTSYS) return err;
@@ -327,7 +327,7 @@ static int p9_get_mapped_pages(struct virtio_chan *chan, * Other zc request to finish here */ if (atomic_read(&vp_pinned) >= chan->p9_max_pages) { - err = wait_event_interruptible(vp_wq, + err = wait_event_killable(vp_wq, (atomic_read(&vp_pinned) < chan->p9_max_pages)); if (err == -ERESTARTSYS) return err; @@ -471,8 +471,8 @@ p9_virtio_zc_request(struct p9_client *client, struct p9_req_t *req, if (err == -ENOSPC) { chan->ring_bufs_avail = 0; spin_unlock_irqrestore(&chan->lock, flags); - err = wait_event_interruptible(*chan->vc_wq, - chan->ring_bufs_avail); + err = wait_event_killable(*chan->vc_wq, + chan->ring_bufs_avail); if (err == -ERESTARTSYS) goto err_out;
@@ -489,8 +489,7 @@ p9_virtio_zc_request(struct p9_client *client, struct p9_req_t *req, virtqueue_kick(chan->vq); spin_unlock_irqrestore(&chan->lock, flags); p9_debug(P9_DEBUG_TRANS, "virtio request kicked\n"); - err = wait_event_interruptible(*req->wq, - req->status >= REQ_STATUS_RCVD); + err = wait_event_killable(*req->wq, req->status >= REQ_STATUS_RCVD); /* * Non kernel buffers are pinned, unpin them */ diff --git a/net/9p/trans_xen.c b/net/9p/trans_xen.c index 6ad3e043c617..325c56043007 100644 --- a/net/9p/trans_xen.c +++ b/net/9p/trans_xen.c @@ -156,8 +156,8 @@ static int p9_xen_request(struct p9_client *client, struct p9_req_t *p9_req) ring = &priv->rings[num];
again: - while (wait_event_interruptible(ring->wq, - p9_xen_write_todo(ring, size)) != 0) + while (wait_event_killable(ring->wq, + p9_xen_write_todo(ring, size)) != 0) ;
spin_lock_irqsave(&ring->lock, flags);