Patch "fuse: clear FR_PENDING flag when moving requests out of pending queue" has been added to the 4.4-stable tree

[<gregkh@linuxfoundation.org>]

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

    fuse: clear FR_PENDING flag when moving requests out of pending queue

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     fuse-clear-fr_pending-flag-when-moving-requests-out-of-pending-queue.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 a8a86d78d673b1c99fe9b0064739fde9e9774184 Mon Sep 17 00:00:00 2001
From: Tahsin Erdogan <tahsin@google.com>
Date: Thu, 12 Jan 2017 12:04:04 -0800
Subject: fuse: clear FR_PENDING flag when moving requests out of pending queue

From: Tahsin Erdogan <tahsin@google.com>

commit a8a86d78d673b1c99fe9b0064739fde9e9774184 upstream.

fuse_abort_conn() moves requests from pending list to a temporary list
before canceling them. This operation races with request_wait_answer()
which also tries to remove the request after it gets a fatal signal. It
checks FR_PENDING flag to determine whether the request is still in the
pending list.

Make fuse_abort_conn() clear FR_PENDING flag so that request_wait_answer()
does not remove the request from temporary list.

This bug causes an Oops when trying to delete an already deleted list entry
in end_requests().

Fixes: ee314a870e40 ("fuse: abort: no fc->lock needed for request ending")
Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/fuse/dev.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -2083,7 +2083,6 @@ static void end_requests(struct fuse_con
 		struct fuse_req *req;
 		req = list_entry(head->next, struct fuse_req, list);
 		req->out.h.error = -ECONNABORTED;
-		clear_bit(FR_PENDING, &req->flags);
 		clear_bit(FR_SENT, &req->flags);
 		list_del_init(&req->list);
 		request_end(fc, req);
@@ -2161,6 +2160,8 @@ void fuse_abort_conn(struct fuse_conn *f
 		spin_lock(&fiq->waitq.lock);
 		fiq->connected = 0;
 		list_splice_init(&fiq->pending, &to_end2);
+		list_for_each_entry(req, &to_end2, list)
+			clear_bit(FR_PENDING, &req->flags);
 		while (forget_pending(fiq))
 			kfree(dequeue_forget(fiq, 1, NULL));
 		wake_up_all_locked(&fiq->waitq);


Patches currently in stable-queue which might be from tahsin@google.com are

queue-4.4/fuse-clear-fr_pending-flag-when-moving-requests-out-of-pending-queue.patch