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[ Upstream commit a17ad0961706244dce48ec941f7e476a38c0e727 ] In some cases skb head could be locked and entire header data is pulled from skb. When skb_zerocopy() called in such cases, following BUG is triggered. This patch fixes it by copying entire skb in such cases. This could be optimized incase this is performance bottleneck. ---8<--- kernel BUG at net/core/skbuff.c:2961! invalid opcode: 0000 [#1] SMP PTI CPU: 2 PID: 0 Comm: swapper/2 Tainted: G OE 5.4.0-77-generic #86-Ubuntu Hardware name: OpenStack Foundation OpenStack Nova, BIOS 1.13.0-1ubuntu1.1 04/01/2014 RIP: 0010:skb_zerocopy+0x37a/0x3a0 RSP: 0018:ffffbcc70013ca38 EFLAGS: 00010246 Call Trace: <IRQ> queue_userspace_packet+0x2af/0x5e0 [openvswitch] ovs_dp_upcall+0x3d/0x60 [openvswitch] ovs_dp_process_packet+0x125/0x150 [openvswitch] ovs_vport_receive+0x77/0xd0 [openvswitch] netdev_port_receive+0x87/0x130 [openvswitch] netdev_frame_hook+0x4b/0x60 [openvswitch] __netif_receive_skb_core+0x2b4/0xc90 __netif_receive_skb_one_core+0x3f/0xa0 __netif_receive_skb+0x18/0x60 process_backlog+0xa9/0x160 net_rx_action+0x142/0x390 __do_softirq+0xe1/0x2d6 irq_exit+0xae/0xb0 do_IRQ+0x5a/0xf0 common_interrupt+0xf/0xf Code that triggered BUG: int skb_zerocopy(struct sk_buff *to, struct sk_buff *from, int len, int hlen) { int i, j = 0; int plen = 0; /* length of skb->head fragment */ int ret; struct page *page; unsigned int offset; BUG_ON(!from->head_frag && !hlen); Signed-off-by: Pravin B Shelar <pshelar@ovn.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.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.