Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.
Michael S. Tsirkin
authored
Resizing currently drops consumer lock. This can cause entries to be reordered, which isn't good in itself. More importantly, consumer can detect a false ring empty condition and block forever. Further, nesting of consumer within producer lock is problematic for tun, since it produces entries in a BH, which causes a lock order reversal: CPU0 CPU1 ---- ---- consume: lock(&(&r->consumer_lock)->rlock); resize: local_irq_disable(); lock(&(&r->producer_lock)->rlock); lock(&(&r->consumer_lock)->rlock); <Interrupt> produce: lock(&(&r->producer_lock)->rlock); To fix, nest producer lock within consumer lock during resize, and keep consumer lock during the whole swap operation. Reported-by:Dmitry Vyukov <dvyukov@google.com> Cc: stable@vger.kernel.org Cc: "David S. Miller" <davem@davemloft.net> Acked-by:
Jason Wang <jasowang@redhat.com> Signed-off-by:
Michael S. Tsirkin <mst@redhat.com> Signed-off-by:
David S. Miller <davem@davemloft.net>