Revision cfc860253abd73e1681696c08ea268d33285a2c4 authored by Paul Mackerras on 20 September 2013, 23:53:28 UTC, committed by Paolo Bonzini on 10 October 2013, 09:40:07 UTC
This fixes a typo in the code that saves the guest DSCR (Data Stream Control Register) into the kvm_vcpu_arch struct on guest exit. The effect of the typo was that the DSCR value was saved in the wrong place, so changes to the DSCR by the guest didn't persist across guest exit and entry, and some host kernel memory got corrupted. Cc: stable@vger.kernel.org [v3.1+] Signed-off-by: Paul Mackerras <paulus@samba.org> Acked-by: Alexander Graf <agraf@suse.de> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
1 parent d0d538b
probe.c
/*
* sctp_probe - Observe the SCTP flow with kprobes.
*
* The idea for this came from Werner Almesberger's umlsim
* Copyright (C) 2004, Stephen Hemminger <shemminger@osdl.org>
*
* Modified for SCTP from Stephen Hemminger's code
* Copyright (C) 2010, Wei Yongjun <yjwei@cn.fujitsu.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/kprobes.h>
#include <linux/socket.h>
#include <linux/sctp.h>
#include <linux/proc_fs.h>
#include <linux/vmalloc.h>
#include <linux/module.h>
#include <linux/kfifo.h>
#include <linux/time.h>
#include <net/net_namespace.h>
#include <net/sctp/sctp.h>
#include <net/sctp/sm.h>
MODULE_AUTHOR("Wei Yongjun <yjwei@cn.fujitsu.com>");
MODULE_DESCRIPTION("SCTP snooper");
MODULE_LICENSE("GPL");
static int port __read_mostly = 0;
MODULE_PARM_DESC(port, "Port to match (0=all)");
module_param(port, int, 0);
static unsigned int fwmark __read_mostly = 0;
MODULE_PARM_DESC(fwmark, "skb mark to match (0=no mark)");
module_param(fwmark, uint, 0);
static int bufsize __read_mostly = 64 * 1024;
MODULE_PARM_DESC(bufsize, "Log buffer size (default 64k)");
module_param(bufsize, int, 0);
static int full __read_mostly = 1;
MODULE_PARM_DESC(full, "Full log (1=every ack packet received, 0=only cwnd changes)");
module_param(full, int, 0);
static const char procname[] = "sctpprobe";
static struct {
struct kfifo fifo;
spinlock_t lock;
wait_queue_head_t wait;
struct timespec tstart;
} sctpw;
static __printf(1, 2) void printl(const char *fmt, ...)
{
va_list args;
int len;
char tbuf[256];
va_start(args, fmt);
len = vscnprintf(tbuf, sizeof(tbuf), fmt, args);
va_end(args);
kfifo_in_locked(&sctpw.fifo, tbuf, len, &sctpw.lock);
wake_up(&sctpw.wait);
}
static int sctpprobe_open(struct inode *inode, struct file *file)
{
kfifo_reset(&sctpw.fifo);
getnstimeofday(&sctpw.tstart);
return 0;
}
static ssize_t sctpprobe_read(struct file *file, char __user *buf,
size_t len, loff_t *ppos)
{
int error = 0, cnt = 0;
unsigned char *tbuf;
if (!buf)
return -EINVAL;
if (len == 0)
return 0;
tbuf = vmalloc(len);
if (!tbuf)
return -ENOMEM;
error = wait_event_interruptible(sctpw.wait,
kfifo_len(&sctpw.fifo) != 0);
if (error)
goto out_free;
cnt = kfifo_out_locked(&sctpw.fifo, tbuf, len, &sctpw.lock);
error = copy_to_user(buf, tbuf, cnt) ? -EFAULT : 0;
out_free:
vfree(tbuf);
return error ? error : cnt;
}
static const struct file_operations sctpprobe_fops = {
.owner = THIS_MODULE,
.open = sctpprobe_open,
.read = sctpprobe_read,
.llseek = noop_llseek,
};
static sctp_disposition_t jsctp_sf_eat_sack(struct net *net,
const struct sctp_endpoint *ep,
const struct sctp_association *asoc,
const sctp_subtype_t type,
void *arg,
sctp_cmd_seq_t *commands)
{
struct sctp_chunk *chunk = arg;
struct sk_buff *skb = chunk->skb;
struct sctp_transport *sp;
static __u32 lcwnd = 0;
struct timespec now;
sp = asoc->peer.primary_path;
if (((port == 0 && fwmark == 0) ||
asoc->peer.port == port ||
ep->base.bind_addr.port == port ||
(fwmark > 0 && skb->mark == fwmark)) &&
(full || sp->cwnd != lcwnd)) {
lcwnd = sp->cwnd;
getnstimeofday(&now);
now = timespec_sub(now, sctpw.tstart);
printl("%lu.%06lu ", (unsigned long) now.tv_sec,
(unsigned long) now.tv_nsec / NSEC_PER_USEC);
printl("%p %5d %5d %5d %8d %5d ", asoc,
ep->base.bind_addr.port, asoc->peer.port,
asoc->pathmtu, asoc->peer.rwnd, asoc->unack_data);
list_for_each_entry(sp, &asoc->peer.transport_addr_list,
transports) {
if (sp == asoc->peer.primary_path)
printl("*");
printl("%pISc %2u %8u %8u %8u %8u %8u ",
&sp->ipaddr, sp->state, sp->cwnd, sp->ssthresh,
sp->flight_size, sp->partial_bytes_acked,
sp->pathmtu);
}
printl("\n");
}
jprobe_return();
return 0;
}
static struct jprobe sctp_recv_probe = {
.kp = {
.symbol_name = "sctp_sf_eat_sack_6_2",
},
.entry = jsctp_sf_eat_sack,
};
static __init int sctpprobe_init(void)
{
int ret = -ENOMEM;
/* Warning: if the function signature of sctp_sf_eat_sack_6_2,
* has been changed, you also have to change the signature of
* jsctp_sf_eat_sack, otherwise you end up right here!
*/
BUILD_BUG_ON(__same_type(sctp_sf_eat_sack_6_2,
jsctp_sf_eat_sack) == 0);
init_waitqueue_head(&sctpw.wait);
spin_lock_init(&sctpw.lock);
if (kfifo_alloc(&sctpw.fifo, bufsize, GFP_KERNEL))
return ret;
if (!proc_create(procname, S_IRUSR, init_net.proc_net,
&sctpprobe_fops))
goto free_kfifo;
ret = register_jprobe(&sctp_recv_probe);
if (ret)
goto remove_proc;
pr_info("probe registered (port=%d/fwmark=%u) bufsize=%u\n",
port, fwmark, bufsize);
return 0;
remove_proc:
remove_proc_entry(procname, init_net.proc_net);
free_kfifo:
kfifo_free(&sctpw.fifo);
return ret;
}
static __exit void sctpprobe_exit(void)
{
kfifo_free(&sctpw.fifo);
remove_proc_entry(procname, init_net.proc_net);
unregister_jprobe(&sctp_recv_probe);
}
module_init(sctpprobe_init);
module_exit(sctpprobe_exit);
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