This is a note to let you know that I've just added the patch titled

net/9p: Switch to wait_event_killable()

to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: net-9p-switch-to-wait_event_killable.patch and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

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: net/9p: Switch to wait_event_killable()

From: Tuomas Tynkkynen tuomas@tuxera.com

commit 9523feac272ccad2ad8186ba4fcc89103754de52 upstream.

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.

Signed-off-by: Tuomas Tynkkynen tuomas@tuxera.com Signed-off-by: Al Viro viro@zeniv.linux.org.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- net/9p/client.c | 3 +-- net/9p/trans_virtio.c | 13 ++++++------- 2 files changed, 7 insertions(+), 9 deletions(-)

--- a/net/9p/client.c +++ b/net/9p/client.c @@ -749,8 +749,7 @@ p9_client_rpc(struct p9_client *c, int8_ } 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 --- a/net/9p/trans_virtio.c +++ b/net/9p/trans_virtio.c @@ -290,8 +290,8 @@ req_retry: 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;

@@ -331,7 +331,7 @@ static int p9_get_mapped_pages(struct vi * 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; @@ -475,8 +475,8 @@ req_retry_pinned: 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;

@@ -493,8 +493,7 @@ req_retry_pinned: 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 */

Patches currently in stable-queue which might be from tuomas@tuxera.com are

queue-4.4/net-9p-switch-to-wait_event_killable.patch queue-4.4/fs-9p-compare-qid.path-in-v9fs_test_inode.patch