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path: root/proto_vlan.c
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/*
 * netsniff-ng - the packet sniffing beast
 * Copyright 2009, 2010 Daniel Borkmann.
 * Copyright 2010 Emmanuel Roullit.
 * Subject to the GPL, version 2.
 */

#include <stdio.h>
#include <stdint.h>
#include <netinet/in.h>    /* for ntohs() */

#include "proto.h"
#include "protos.h"
#include "dissector_eth.h"
#include "pkt_buff.h"

struct vlanhdr {
	uint16_t h_vlan_TCI;
	uint16_t h_vlan_encapsulated_proto;
} __attribute__((packed));

static void vlan(struct pkt_buff *pkt)
{
	uint16_t tci;
	struct vlanhdr *vlan = (struct vlanhdr *) pkt_pull(pkt, sizeof(*vlan));

	if (vlan == NULL)
		return;

	tci = ntohs(vlan->h_vlan_TCI);

	tprintf(" [ VLAN ");
	tprintf("Prio (%d), ", (tci & 0xE000) >> 13);
	tprintf("CFI (%d), ", (tci & 0x1000) >> 12);
	tprintf("ID (%d), ", (tci & 0x0FFF));
	tprintf("Proto (0x%.4x)", ntohs(vlan->h_vlan_encapsulated_proto));
	tprintf(" ]\n");

	pkt_set_proto(pkt, &eth_lay2, ntohs(vlan->h_vlan_encapsulated_proto));
}

static void vlan_less(struct pkt_buff *pkt)
{
	uint16_t tci;
	struct vlanhdr *vlan = (struct vlanhdr *) pkt_pull(pkt, sizeof(*vlan));

	if (vlan == NULL)
		return;

	tci = ntohs(vlan->h_vlan_TCI);

	tprintf(" VLAN%d", (tci & 0x0FFF));

	pkt_set_proto(pkt, &eth_lay2, ntohs(vlan->h_vlan_encapsulated_proto));
}

struct protocol vlan_ops = {
	.key = 0x8100,
	.print_full = vlan,
	.print_less = vlan_less,
};
-3 and only CPU0 is online: ======================== =========================== cpu_online_mask top_cpuset.effective_cpus ======================== =========================== echo 1 > cpu2/online. CPU hotplug notifier woke up hotplug work but not yet scheduled. [0,2] [0] echo 0 > cpu0/online. The workqueue is still runnable. [2] [0] ======================== =========================== Now there is no intersection between cpu_online_mask and top_cpuset.effective_cpus. Thus invoking sys_sched_setaffinity() at this moment can cause following: Unable to handle kernel NULL pointer dereference at virtual address 000000d0 ------------[ cut here ]------------ Kernel BUG at ffffffc0001389b0 [verbose debug info unavailable] Internal error: Oops - BUG: 96000005 [#1] PREEMPT SMP Modules linked in: CPU: 2 PID: 1420 Comm: taskset Tainted: G W 4.4.8+ #98 task: ffffffc06a5c4880 ti: ffffffc06e124000 task.ti: ffffffc06e124000 PC is at guarantee_online_cpus+0x2c/0x58 LR is at cpuset_cpus_allowed+0x4c/0x6c <snip> Process taskset (pid: 1420, stack limit = 0xffffffc06e124020) Call trace: [<ffffffc0001389b0>] guarantee_online_cpus+0x2c/0x58 [<ffffffc00013b208>] cpuset_cpus_allowed+0x4c/0x6c [<ffffffc0000d61f0>] sched_setaffinity+0xc0/0x1ac [<ffffffc0000d6374>] SyS_sched_setaffinity+0x98/0xac [<ffffffc000085cb0>] el0_svc_naked+0x24/0x28 The top cpuset's effective_cpus are guaranteed to be identical to cpu_online_mask eventually. Hence fall back to cpu_online_mask when there is no intersection between top cpuset's effective_cpus and cpu_online_mask. Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Tejun Heo <tj@kernel.org> Cc: cgroups@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: <stable@vger.kernel.org> # 3.17+ Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'Documentation')