OpenE2K/linux
6
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

fuse: check connected before queueing on fpq->io

Browse Source 
commit 80ef08670d4c28a06a3de954bd350368780bcfef upstream.

A request could end up on the fpq->io list after fuse_abort_conn() has
reset fpq->connected and aborted requests on that list:

Thread-1			  Thread-2
========			  ========
->fuse_simple_request()           ->shutdown
  ->__fuse_request_send()
    ->queue_request()		->fuse_abort_conn()
->fuse_dev_do_read()                ->acquire(fpq->lock)
  ->wait_for(fpq->lock) 	  ->set err to all req's in fpq->io
				  ->release(fpq->lock)
  ->acquire(fpq->lock)
  ->add req to fpq->io

After the userspace copy is done the request will be ended, but
req->out.h.error will remain uninitialized.  Also the copy might block
despite being already aborted.

Fix both issues by not allowing the request to be queued on the fpq->io
list after fuse_abort_conn() has processed this list.

Reported-by: Pradeep P V K <pragalla@codeaurora.org>
Fixes: fd22d62ed0 ("fuse: no fc->lock for iqueue parts")
Cc: <stable@vger.kernel.org> # v4.2
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Miklos Szeredi 2021-06-22 09:15:35 +02:00 committed by Greg Kroah-Hartman
parent e72bec9226
commit 059dd690bf
1 changed files with 9 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
fs/fuse/dev.c
View File

@ -1264,6 +1264,15 @@ static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file,
goto restart;
}
spin_lock(&fpq->lock);
/*
* Must not put request on fpq->io queue after having been shut down by
* fuse_abort_conn()
*/
if (!fpq->connected) {
req->out.h.error = err = -ECONNABORTED;
goto out_end;
}
list_add(&req->list, &fpq->io);
spin_unlock(&fpq->lock);
cs->req = req;