Eric Dumazet
945d182a04
commitb160c28548upstream. Heiner Kallweit reported that some skbs were sent with the following invalid GSO properties : - gso_size > 0 - gso_type == 0 This was triggerring a WARN_ON_ONCE() in rtl8169_tso_csum_v2. Juerg Haefliger was able to reproduce a similar issue using a lan78xx NIC and a workload mixing TCP incoming traffic and forwarded packets. The problem is that tcp_add_backlog() is writing over gso_segs and gso_size even if the incoming packet will not be coalesced to the backlog tail packet. While skb_try_coalesce() would bail out if tail packet is cloned, this overwriting would lead to corruptions of other packets cooked by lan78xx, sharing a common super-packet. The strategy used by lan78xx is to use a big skb, and split it into all received packets using skb_clone() to avoid copies. The drawback of this strategy is that all the small skb share a common struct skb_shared_info. This patch rewrites TCP gso_size/gso_segs handling to only happen on the tail skb, since skb_try_coalesce() made sure it was not cloned. Fixes:4f693b55c3("tcp: implement coalescing on backlog queue") Signed-off-by: Eric Dumazet <edumazet@google.com> Bisected-by: Juerg Haefliger <juergh@canonical.com> Tested-by: Juerg Haefliger <juergh@canonical.com> Reported-by: Heiner Kallweit <hkallweit1@gmail.com> Link: https://bugzilla.kernel.org/show_bug.cgi?id=209423 Link: https://lore.kernel.org/r/20210119164900.766957-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
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.