Merge tag 'uml-for-linus-6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux

Pull UML updates from Richard Weinberger:

 - Support for preemption

 - i386 Rust support

 - Huge cleanup by Benjamin Berg

 - UBSAN support

 - Removal of dead code

* tag 'uml-for-linus-6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux: (41 commits)
  um: vector: always reset vp->opened
  um: vector: remove vp->lock
  um: register power-off handler
  um: line: always fill *error_out in setup_one_line()
  um: remove pcap driver from documentation
  um: Enable preemption in UML
  um: refactor TLB update handling
  um: simplify and consolidate TLB updates
  um: remove force_flush_all from fork_handler
  um: Do not flush MM in flush_thread
  um: Delay flushing syscalls until the thread is restarted
  um: remove copy_context_skas0
  um: remove LDT support
  um: compress memory related stub syscalls while adding them
  um: Rework syscall handling
  um: Add generic stub_syscall6 function
  um: Create signal stack memory assignment in stub_data
  um: Remove stub-data.h include from common-offsets.h
  um: time-travel: fix signal blocking race/hang
  um: time-travel: remove time_exit()
  ...

16 files changed, 106 insertions, 354 deletions

diff --git a/arch/um/drivers/Kconfig b/arch/um/drivers/Kconfig
index b94b2618e7d8..ede40a160c5e 100644
--- a/arch/um/drivers/Kconfig
+++ b/arch/um/drivers/Kconfig
@@ -297,26 +297,6 @@ config UML_NET_MCAST
 
 	  If unsure, say N.
 
-config UML_NET_PCAP
-	bool "pcap transport (obsolete)"
-	depends on UML_NET
-	depends on !MODVERSIONS
-	select MAY_HAVE_RUNTIME_DEPS
-	help
-	  The pcap transport makes a pcap packet stream on the host look
-	  like an ethernet device inside UML.  This is useful for making
-	  UML act as a network monitor for the host.  You must have libcap
-	  installed in order to build the pcap transport into UML.
-
-	  For more information, see
-	  <http://user-mode-linux.sourceforge.net/old/networking.html>  That site
-	  has examples of the UML command line to use to enable this option.
-
-	  NOTE: THIS TRANSPORT IS DEPRECATED AND WILL BE REMOVED SOON!!! Please
-	  migrate to UML_NET_VECTOR.
-
-	  If unsure, say N.
-
 config UML_NET_SLIRP
 	bool "SLiRP transport (obsolete)"
 	depends on UML_NET
diff --git a/arch/um/drivers/Makefile b/arch/um/drivers/Makefile
index 0e6af81096fd..57882e6bc215 100644
--- a/arch/um/drivers/Makefile
+++ b/arch/um/drivers/Makefile
@@ -20,14 +20,9 @@ harddog-objs := harddog_kern.o
 harddog-builtin-$(CONFIG_UML_WATCHDOG) := harddog_user.o harddog_user_exp.o
 rtc-objs := rtc_kern.o rtc_user.o
 
-LDFLAGS_pcap.o = $(shell $(CC) $(KBUILD_CFLAGS) -print-file-name=libpcap.a)
-
 LDFLAGS_vde.o = $(shell $(CC) $(CFLAGS) -print-file-name=libvdeplug.a)
 
-targets := pcap_kern.o pcap_user.o vde_kern.o vde_user.o
-
-$(obj)/pcap.o: $(obj)/pcap_kern.o $(obj)/pcap_user.o
-	$(LD) -r -dp -o $@ $^ $(ld_flags)
+targets := vde_kern.o vde_user.o
 
 $(obj)/vde.o: $(obj)/vde_kern.o $(obj)/vde_user.o
 	$(LD) -r -dp -o $@ $^ $(ld_flags)
@@ -49,7 +44,6 @@ obj-$(CONFIG_UML_NET_DAEMON) += daemon.o
 obj-$(CONFIG_UML_NET_VECTOR) += vector.o
 obj-$(CONFIG_UML_NET_VDE) += vde.o
 obj-$(CONFIG_UML_NET_MCAST) += umcast.o
-obj-$(CONFIG_UML_NET_PCAP) += pcap.o
 obj-$(CONFIG_UML_NET) += net.o 
 obj-$(CONFIG_MCONSOLE) += mconsole.o
 obj-$(CONFIG_MMAPPER) += mmapper_kern.o 
@@ -69,7 +63,7 @@ obj-$(CONFIG_UML_RTC) += rtc.o
 obj-$(CONFIG_UML_PCI_OVER_VIRTIO) += virt-pci.o
 
 # pcap_user.o must be added explicitly.
-USER_OBJS := fd.o null.o pty.o tty.o xterm.o slip_common.o pcap_user.o vde_user.o vector_user.o
+USER_OBJS := fd.o null.o pty.o tty.o xterm.o slip_common.o vde_user.o vector_user.o
 CFLAGS_null.o = -DDEV_NULL=$(DEV_NULL_PATH)
 
 CFLAGS_xterm.o += '-DCONFIG_XTERM_CHAN_DEFAULT_EMULATOR="$(CONFIG_XTERM_CHAN_DEFAULT_EMULATOR)"'
diff --git a/arch/um/drivers/chan.h b/arch/um/drivers/chan.h
index e14b9cdf7a33..5a61db512ffb 100644
--- a/arch/um/drivers/chan.h
+++ b/arch/um/drivers/chan.h
@@ -22,7 +22,8 @@ struct chan {
 	unsigned int output:1;
 	unsigned int opened:1;
 	unsigned int enabled:1;
-	int fd;
+	int fd_in;
+	int fd_out; /* only different to fd_in if blocking output is needed */
 	const struct chan_ops *ops;
 	void *data;
 };
diff --git a/arch/um/drivers/chan_kern.c b/arch/um/drivers/chan_kern.c
index 37538b4168da..e78a99816c86 100644
--- a/arch/um/drivers/chan_kern.c
+++ b/arch/um/drivers/chan_kern.c
@@ -81,6 +81,12 @@ static const struct chan_ops not_configged_ops = {
 };
 #endif /* CONFIG_NOCONFIG_CHAN */
 
+static inline bool need_output_blocking(void)
+{
+	return time_travel_mode == TT_MODE_INFCPU ||
+	       time_travel_mode == TT_MODE_EXTERNAL;
+}
+
 static int open_one_chan(struct chan *chan)
 {
 	int fd, err;
@@ -96,15 +102,43 @@ static int open_one_chan(struct chan *chan)
 		return fd;
 
 	err = os_set_fd_block(fd, 0);
-	if (err) {
-		(*chan->ops->close)(fd, chan->data);
-		return err;
-	}
+	if (err)
+		goto out_close;
+
+	chan->fd_in = fd;
+	chan->fd_out = fd;
+
+	/*
+	 * In time-travel modes infinite-CPU and external we need to guarantee
+	 * that any writes to the output succeed immdiately from the point of
+	 * the VM. The best way to do this is to put the FD in blocking mode
+	 * and simply wait/retry until everything is written.
+	 * As every write is guaranteed to complete, we also do not need to
+	 * request an IRQ for the output.
+	 *
+	 * Note that input cannot happen in a time synchronized way. We permit
+	 * it, but time passes very quickly if anything waits for a read.
+	 */
+	if (chan->output && need_output_blocking()) {
+		err = os_dup_file(chan->fd_out);
+		if (err < 0)
+			goto out_close;
 
-	chan->fd = fd;
+		chan->fd_out = err;
+
+		err = os_set_fd_block(chan->fd_out, 1);
+		if (err) {
+			os_close_file(chan->fd_out);
+			goto out_close;
+		}
+	}
 
 	chan->opened = 1;
 	return 0;
+
+out_close:
+	(*chan->ops->close)(fd, chan->data);
+	return err;
 }
 
 static int open_chan(struct list_head *chans)
@@ -125,7 +159,7 @@ static int open_chan(struct list_head *chans)
 void chan_enable_winch(struct chan *chan, struct tty_port *port)
 {
 	if (chan && chan->primary && chan->ops->winch)
-		register_winch(chan->fd, port);
+		register_winch(chan->fd_in, port);
 }
 
 static void line_timer_cb(struct work_struct *work)
@@ -156,8 +190,9 @@ int enable_chan(struct line *line)
 
 		if (chan->enabled)
 			continue;
-		err = line_setup_irq(chan->fd, chan->input, chan->output, line,
-				     chan);
+		err = line_setup_irq(chan->fd_in, chan->input,
+				     chan->output && !need_output_blocking(),
+				     line, chan);
 		if (err)
 			goto out_close;
 
@@ -196,7 +231,8 @@ void free_irqs(void)
 
 		if (chan->input && chan->enabled)
 			um_free_irq(chan->line->read_irq, chan);
-		if (chan->output && chan->enabled)
+		if (chan->output && chan->enabled &&
+		    !need_output_blocking())
 			um_free_irq(chan->line->write_irq, chan);
 		chan->enabled = 0;
 	}
@@ -216,15 +252,19 @@ static void close_one_chan(struct chan *chan, int delay_free_irq)
 	} else {
 		if (chan->input && chan->enabled)
 			um_free_irq(chan->line->read_irq, chan);
-		if (chan->output && chan->enabled)
+		if (chan->output && chan->enabled &&
+		    !need_output_blocking())
 			um_free_irq(chan->line->write_irq, chan);
 		chan->enabled = 0;
 	}
+	if (chan->fd_out != chan->fd_in)
+		os_close_file(chan->fd_out);
 	if (chan->ops->close != NULL)
-		(*chan->ops->close)(chan->fd, chan->data);
+		(*chan->ops->close)(chan->fd_in, chan->data);
 
 	chan->opened = 0;
-	chan->fd = -1;
+	chan->fd_in = -1;
+	chan->fd_out = -1;
 }
 
 void close_chan(struct line *line)
@@ -244,7 +284,7 @@ void close_chan(struct line *line)
 void deactivate_chan(struct chan *chan, int irq)
 {
 	if (chan && chan->enabled)
-		deactivate_fd(chan->fd, irq);
+		deactivate_fd(chan->fd_in, irq);
 }
 
 int write_chan(struct chan *chan, const u8 *buf, size_t len, int write_irq)
@@ -254,7 +294,7 @@ int write_chan(struct chan *chan, const u8 *buf, size_t len, int write_irq)
 	if (len == 0 || !chan || !chan->ops->write)
 		return 0;
 
-	n = chan->ops->write(chan->fd, buf, len, chan->data);
+	n = chan->ops->write(chan->fd_out, buf, len, chan->data);
 	if (chan->primary) {
 		ret = n;
 	}
@@ -268,7 +308,7 @@ int console_write_chan(struct chan *chan, const char *buf, int len)
 	if (!chan || !chan->ops->console_write)
 		return 0;
 
-	n = chan->ops->console_write(chan->fd, buf, len);
+	n = chan->ops->console_write(chan->fd_out, buf, len);
 	if (chan->primary)
 		ret = n;
 	return ret;
@@ -296,14 +336,14 @@ int chan_window_size(struct line *line, unsigned short *rows_out,
 	if (chan && chan->primary) {
 		if (chan->ops->window_size == NULL)
 			return 0;
-		return chan->ops->window_size(chan->fd, chan->data,
+		return chan->ops->window_size(chan->fd_in, chan->data,
 					      rows_out, cols_out);
 	}
 	chan = line->chan_out;
 	if (chan && chan->primary) {
 		if (chan->ops->window_size == NULL)
 			return 0;
-		return chan->ops->window_size(chan->fd, chan->data,
+		return chan->ops->window_size(chan->fd_in, chan->data,
 					      rows_out, cols_out);
 	}
 	return 0;
@@ -319,7 +359,7 @@ static void free_one_chan(struct chan *chan)
 		(*chan->ops->free)(chan->data);
 
 	if (chan->primary && chan->output)
-		ignore_sigio_fd(chan->fd);
+		ignore_sigio_fd(chan->fd_in);
 	kfree(chan);
 }
 
@@ -478,7 +518,8 @@ static struct chan *parse_chan(struct line *line, char *str, int device,
 				 .output 	= 0,
 				 .opened  	= 0,
 				 .enabled  	= 0,
-				 .fd 		= -1,
+				 .fd_in		= -1,
+				 .fd_out	= -1,
 				 .ops 		= ops,
 				 .data 		= data });
 	return chan;
@@ -549,7 +590,7 @@ void chan_interrupt(struct line *line, int irq)
 			schedule_delayed_work(&line->task, 1);
 			goto out;
 		}
-		err = chan->ops->read(chan->fd, &c, chan->data);
+		err = chan->ops->read(chan->fd_in, &c, chan->data);
 		if (err > 0)
 			tty_insert_flip_char(port, c, TTY_NORMAL);
 	} while (err > 0);
diff --git a/arch/um/drivers/chan_user.c b/arch/um/drivers/chan_user.c
index ec04e47b9d79..a66e556012c4 100644
--- a/arch/um/drivers/chan_user.c
+++ b/arch/um/drivers/chan_user.c
@@ -23,7 +23,7 @@ int generic_read(int fd, __u8 *c_out, void *unused)
 {
 	int n;
 
-	n = read(fd, c_out, sizeof(*c_out));
+	CATCH_EINTR(n = read(fd, c_out, sizeof(*c_out)));
 	if (n > 0)
 		return n;
 	else if (n == 0)
@@ -37,11 +37,23 @@ int generic_read(int fd, __u8 *c_out, void *unused)
 
 int generic_write(int fd, const __u8 *buf, size_t n, void *unused)
 {
+	int written = 0;
 	int err;
 
-	err = write(fd, buf, n);
-	if (err > 0)
-		return err;
+	/* The FD may be in blocking mode, as such, need to retry short writes,
+	 * they may have been interrupted by a signal.
+	 */
+	do {
+		errno = 0;
+		err = write(fd, buf + written, n - written);
+		if (err > 0) {
+			written += err;
+			continue;
+		}
+	} while (err < 0 && errno == EINTR);
+
+	if (written > 0)
+		return written;
 	else if (errno == EAGAIN)
 		return 0;
 	else if (err == 0)
diff --git a/arch/um/drivers/harddog_kern.c b/arch/um/drivers/harddog_kern.c
index 60d1c6cab8a9..99a7144b229f 100644
--- a/arch/um/drivers/harddog_kern.c
+++ b/arch/um/drivers/harddog_kern.c
@@ -49,6 +49,7 @@
 #include "mconsole.h"
 #include "harddog.h"
 
+MODULE_DESCRIPTION("UML hardware watchdog");
 MODULE_LICENSE("GPL");
 
 static DEFINE_MUTEX(harddog_mutex);
diff --git a/arch/um/drivers/line.c b/arch/um/drivers/line.c
index d82bc3fdb86e..43d8959cc746 100644
--- a/arch/um/drivers/line.c
+++ b/arch/um/drivers/line.c
@@ -383,6 +383,7 @@ int setup_one_line(struct line *lines, int n, char *init,
 			parse_chan_pair(NULL, line, n, opts, error_out);
 			err = 0;
 		}
+		*error_out = "configured as 'none'";
 	} else {
 		char *new = kstrdup(init, GFP_KERNEL);
 		if (!new) {
@@ -406,6 +407,7 @@ int setup_one_line(struct line *lines, int n, char *init,
 			}
 		}
 		if (err) {
+			*error_out = "failed to parse channel pair";
 			line->init_str = NULL;
 			line->valid = 0;
 			kfree(new);
diff --git a/arch/um/drivers/pcap_kern.c b/arch/um/drivers/pcap_kern.c
deleted file mode 100644
index d9bf95d7867b..000000000000
--- a/arch/um/drivers/pcap_kern.c
+++ /dev/null
@@ -1,113 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
- */
-
-#include <linux/init.h>
-#include <linux/netdevice.h>
-#include <net_kern.h>
-#include "pcap_user.h"
-
-struct pcap_init {
-	char *host_if;
-	int promisc;
-	int optimize;
-	char *filter;
-};
-
-static void pcap_init_kern(struct net_device *dev, void *data)
-{
-	struct uml_net_private *pri;
-	struct pcap_data *ppri;
-	struct pcap_init *init = data;
-
-	pri = netdev_priv(dev);
-	ppri = (struct pcap_data *) pri->user;
-	ppri->host_if = init->host_if;
-	ppri->promisc = init->promisc;
-	ppri->optimize = init->optimize;
-	ppri->filter = init->filter;
-
-	printk("pcap backend, host interface %s\n", ppri->host_if);
-}
-
-static int pcap_read(int fd, struct sk_buff *skb, struct uml_net_private *lp)
-{
-	return pcap_user_read(fd, skb_mac_header(skb),
-			      skb->dev->mtu + ETH_HEADER_OTHER,
-			      (struct pcap_data *) &lp->user);
-}
-
-static int pcap_write(int fd, struct sk_buff *skb, struct uml_net_private *lp)
-{
-	return -EPERM;
-}
-
-static const struct net_kern_info pcap_kern_info = {
-	.init			= pcap_init_kern,
-	.protocol		= eth_protocol,
-	.read			= pcap_read,
-	.write			= pcap_write,
-};
-
-static int pcap_setup(char *str, char **mac_out, void *data)
-{
-	struct pcap_init *init = data;
-	char *remain, *host_if = NULL, *options[2] = { NULL, NULL };
-	int i;
-
-	*init = ((struct pcap_init)
-		{ .host_if 	= "eth0",
-		  .promisc 	= 1,
-		  .optimize 	= 0,
-		  .filter 	= NULL });
-
-	remain = split_if_spec(str, &host_if, &init->filter,
-			       &options[0], &options[1], mac_out, NULL);
-	if (remain != NULL) {
-		printk(KERN_ERR "pcap_setup - Extra garbage on "
-		       "specification : '%s'\n", remain);
-		return 0;
-	}
-
-	if (host_if != NULL)
-		init->host_if = host_if;
-
-	for (i = 0; i < ARRAY_SIZE(options); i++) {
-		if (options[i] == NULL)
-			continue;
-		if (!strcmp(options[i], "promisc"))
-			init->promisc = 1;
-		else if (!strcmp(options[i], "nopromisc"))
-			init->promisc = 0;
-		else if (!strcmp(options[i], "optimize"))
-			init->optimize = 1;
-		else if (!strcmp(options[i], "nooptimize"))
-			init->optimize = 0;
-		else {
-			printk(KERN_ERR "pcap_setup : bad option - '%s'\n",
-			       options[i]);
-			return 0;
-		}
-	}
-
-	return 1;
-}
-
-static struct transport pcap_transport = {
-	.list 		= LIST_HEAD_INIT(pcap_transport.list),
-	.name 		= "pcap",
-	.setup  	= pcap_setup,
-	.user 		= &pcap_user_info,
-	.kern 		= &pcap_kern_info,
-	.private_size 	= sizeof(struct pcap_data),
-	.setup_size 	= sizeof(struct pcap_init),
-};
-
-static int register_pcap(void)
-{
-	register_transport(&pcap_transport);
-	return 0;
-}
-
-late_initcall(register_pcap);
diff --git a/arch/um/drivers/pcap_user.c b/arch/um/drivers/pcap_user.c
deleted file mode 100644
index 52ddda3e3b10..000000000000
--- a/arch/um/drivers/pcap_user.c
+++ /dev/null
@@ -1,137 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
- */
-
-#include <errno.h>
-#include <pcap.h>
-#include <string.h>
-#include <asm/types.h>
-#include <net_user.h>
-#include "pcap_user.h"
-#include <um_malloc.h>
-
-#define PCAP_FD(p) (*(int *)(p))
-
-static int pcap_user_init(void *data, void *dev)
-{
-	struct pcap_data *pri = data;
-	pcap_t *p;
-	char errors[PCAP_ERRBUF_SIZE];
-
-	p = pcap_open_live(pri->host_if, ETH_MAX_PACKET + ETH_HEADER_OTHER,
-			   pri->promisc, 0, errors);
-	if (p == NULL) {
-		printk(UM_KERN_ERR "pcap_user_init : pcap_open_live failed - "
-		       "'%s'\n", errors);
-		return -EINVAL;
-	}
-
-	pri->dev = dev;
-	pri->pcap = p;
-	return 0;
-}
-
-static int pcap_user_open(void *data)
-{
-	struct pcap_data *pri = data;
-	__u32 netmask;
-	int err;
-
-	if (pri->pcap == NULL)
-		return -ENODEV;
-
-	if (pri->filter != NULL) {
-		err = dev_netmask(pri->dev, &netmask);
-		if (err < 0) {
-			printk(UM_KERN_ERR "pcap_user_open : dev_netmask failed\n");
-			return -EIO;
-		}
-
-		pri->compiled = uml_kmalloc(sizeof(struct bpf_program),
-					UM_GFP_KERNEL);
-		if (pri->compiled == NULL) {
-			printk(UM_KERN_ERR "pcap_user_open : kmalloc failed\n");
-			return -ENOMEM;
-		}
-
-		err = pcap_compile(pri->pcap,
-				   (struct bpf_program *) pri->compiled,
-				   pri->filter, pri->optimize, netmask);
-		if (err < 0) {
-			printk(UM_KERN_ERR "pcap_user_open : pcap_compile failed - "
-			       "'%s'\n", pcap_geterr(pri->pcap));
-			goto out;
-		}
-
-		err = pcap_setfilter(pri->pcap, pri->compiled);
-		if (err < 0) {
-			printk(UM_KERN_ERR "pcap_user_open : pcap_setfilter "
-			       "failed - '%s'\n", pcap_geterr(pri->pcap));
-			goto out;
-		}
-	}
-
-	return PCAP_FD(pri->pcap);
-
- out:
-	kfree(pri->compiled);
-	return -EIO;
-}
-
-static void pcap_remove(void *data)
-{
-	struct pcap_data *pri = data;
-
-	if (pri->compiled != NULL)
-		pcap_freecode(pri->compiled);
-
-	if (pri->pcap != NULL)
-		pcap_close(pri->pcap);
-}
-
-struct pcap_handler_data {
-	char *buffer;
-	int len;
-};
-
-static void handler(u_char *data, const struct pcap_pkthdr *header,
-		    const u_char *packet)
-{
-	int len;
-
-	struct pcap_handler_data *hdata = (struct pcap_handler_data *) data;
-
-	len = hdata->len < header->caplen ? hdata->len : header->caplen;
-	memcpy(hdata->buffer, packet, len);
-	hdata->len = len;
-}
-
-int pcap_user_read(int fd, void *buffer, int len, struct pcap_data *pri)
-{
-	struct pcap_handler_data hdata = ((struct pcap_handler_data)
-		                          { .buffer  	= buffer,
-					    .len 	= len });
-	int n;
-
-	n = pcap_dispatch(pri->pcap, 1, handler, (u_char *) &hdata);
-	if (n < 0) {
-		printk(UM_KERN_ERR "pcap_dispatch failed - %s\n",
-		       pcap_geterr(pri->pcap));
-		return -EIO;
-	}
-	else if (n == 0)
-		return 0;
-	return hdata.len;
-}
-
-const struct net_user_info pcap_user_info = {
-	.init		= pcap_user_init,
-	.open		= pcap_user_open,
-	.close	 	= NULL,
-	.remove	 	= pcap_remove,
-	.add_address	= NULL,
-	.delete_address = NULL,
-	.mtu		= ETH_MAX_PACKET,
-	.max_packet	= ETH_MAX_PACKET + ETH_HEADER_OTHER,
-};
diff --git a/arch/um/drivers/pcap_user.h b/arch/um/drivers/pcap_user.h
deleted file mode 100644
index 216246f5f09b..000000000000
--- a/arch/um/drivers/pcap_user.h
+++ /dev/null
@@ -1,21 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/* 
- * Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
- */
-
-#include <net_user.h>
-
-struct pcap_data {
-	char *host_if;
-	int promisc;
-	int optimize;
-	char *filter;
-	void *compiled;
-	void *pcap;
-	void *dev;
-};
-
-extern const struct net_user_info pcap_user_info;
-
-extern int pcap_user_read(int fd, void *buf, int len, struct pcap_data *pri);
-
diff --git a/arch/um/drivers/port_kern.c b/arch/um/drivers/port_kern.c
index c52b3ff3c092..a4508470df78 100644
--- a/arch/um/drivers/port_kern.c
+++ b/arch/um/drivers/port_kern.c
@@ -45,15 +45,17 @@ struct connection {
 static irqreturn_t pipe_interrupt(int irq, void *data)
 {
 	struct connection *conn = data;
-	int fd;
+	int n_fds = 1, fd = -1;
+	ssize_t ret;
 
-	fd = os_rcv_fd(conn->socket[0], &conn->helper_pid);
-	if (fd < 0) {
-		if (fd == -EAGAIN)
+	ret = os_rcv_fd_msg(conn->socket[0], &fd, n_fds, &conn->helper_pid,
+			    sizeof(conn->helper_pid));
+	if (ret != sizeof(conn->helper_pid)) {
+		if (ret == -EAGAIN)
 			return IRQ_NONE;
 
-		printk(KERN_ERR "pipe_interrupt : os_rcv_fd returned %d\n",
-		       -fd);
+		printk(KERN_ERR "pipe_interrupt : os_rcv_fd_msg returned %zd\n",
+		       ret);
 		os_close_file(conn->fd);
 	}
 
diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index 9f1e76ddda5a..7f28ec1929dc 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -36,7 +36,6 @@
 #include <linux/vmalloc.h>
 #include <linux/platform_device.h>
 #include <linux/scatterlist.h>
-#include <asm/tlbflush.h>
 #include <kern_util.h>
 #include "mconsole_kern.h"
 #include <init.h>
@@ -106,7 +105,6 @@ static inline void ubd_set_bit(__u64 bit, unsigned char *data)
 #define DRIVER_NAME "uml-blkdev"
 
 static DEFINE_MUTEX(ubd_lock);
-static DEFINE_MUTEX(ubd_mutex); /* replaces BKL, might not be needed */
 
 static int ubd_ioctl(struct block_device *bdev, blk_mode_t mode,
 		     unsigned int cmd, unsigned long arg);
@@ -759,7 +757,6 @@ static int ubd_open_dev(struct ubd *ubd_dev)
 			printk(KERN_ERR "Failed to vmalloc COW bitmap\n");
 			goto error;
 		}
-		flush_tlb_kernel_vm();
 
 		err = read_cow_bitmap(ubd_dev->fd, ubd_dev->cow.bitmap,
 				      ubd_dev->cow.bitmap_offset,
diff --git a/arch/um/drivers/vector_kern.c b/arch/um/drivers/vector_kern.c
index 4279793b11b7..2d473282ab51 100644
--- a/arch/um/drivers/vector_kern.c
+++ b/arch/um/drivers/vector_kern.c
@@ -1115,11 +1115,12 @@ static int irq_rr;
 static int vector_net_close(struct net_device *dev)
 {
 	struct vector_private *vp = netdev_priv(dev);
-	unsigned long flags;
 
 	netif_stop_queue(dev);
 	del_timer(&vp->tl);
 
+	vp->opened = false;
+
 	if (vp->fds == NULL)
 		return 0;
 
@@ -1158,10 +1159,7 @@ static int vector_net_close(struct net_device *dev)
 		destroy_queue(vp->tx_queue);
 	kfree(vp->fds);
 	vp->fds = NULL;
-	spin_lock_irqsave(&vp->lock, flags);
-	vp->opened = false;
 	vp->in_error = false;
-	spin_unlock_irqrestore(&vp->lock, flags);
 	return 0;
 }
 
@@ -1203,17 +1201,12 @@ static void vector_reset_tx(struct work_struct *work)
 static int vector_net_open(struct net_device *dev)
 {
 	struct vector_private *vp = netdev_priv(dev);
-	unsigned long flags;
 	int err = -EINVAL;
 	struct vector_device *vdevice;
 
-	spin_lock_irqsave(&vp->lock, flags);
-	if (vp->opened) {
-		spin_unlock_irqrestore(&vp->lock, flags);
+	if (vp->opened)
 		return -ENXIO;
-	}
 	vp->opened = true;
-	spin_unlock_irqrestore(&vp->lock, flags);
 
 	vp->bpf = uml_vector_user_bpf(get_bpf_file(vp->parsed));
 
@@ -1387,8 +1380,6 @@ static int vector_net_load_bpf_flash(struct net_device *dev,
 		return -1;
 	}
 
-	spin_lock(&vp->lock);
-
 	if (vp->bpf != NULL) {
 		if (vp->opened)
 			uml_vector_detach_bpf(vp->fds->rx_fd, vp->bpf);
@@ -1417,15 +1408,12 @@ static int vector_net_load_bpf_flash(struct net_device *dev,
 	if (vp->opened)
 		result = uml_vector_attach_bpf(vp->fds->rx_fd, vp->bpf);
 
-	spin_unlock(&vp->lock);
-
 	return result;
 
 free_buffer:
 	release_firmware(fw);
 
 flash_fail:
-	spin_unlock(&vp->lock);
 	if (vp->bpf != NULL)
 		kfree(vp->bpf->filter);
 	kfree(vp->bpf);
@@ -1631,7 +1619,6 @@ static void vector_eth_configure(
 	INIT_WORK(&vp->reset_tx, vector_reset_tx);
 
 	timer_setup(&vp->tl, vector_timer_expire, 0);
-	spin_lock_init(&vp->lock);
 
 	/* FIXME */
 	dev->netdev_ops = &vector_netdev_ops;
diff --git a/arch/um/drivers/vector_kern.h b/arch/um/drivers/vector_kern.h
index 2a1fa8e0f3e1..806df551be0b 100644
--- a/arch/um/drivers/vector_kern.h
+++ b/arch/um/drivers/vector_kern.h
@@ -71,7 +71,6 @@ struct vector_estats {
 
 struct vector_private {
 	struct list_head list;
-	spinlock_t lock;
 	struct net_device *dev;
 	struct napi_struct		napi	____cacheline_aligned;
 
diff --git a/arch/um/drivers/xterm.c b/arch/um/drivers/xterm.c
index 6918de5e2956..e4316c7981e8 100644
--- a/arch/um/drivers/xterm.c
+++ b/arch/um/drivers/xterm.c
@@ -156,7 +156,7 @@ static int xterm_open(int input, int output, int primary, void *d,
 	new = xterm_fd(fd, &data->helper_pid);
 	if (new < 0) {
 		err = new;
-		printk(UM_KERN_ERR "xterm_open : os_rcv_fd failed, err = %d\n",
+		printk(UM_KERN_ERR "xterm_open : xterm_fd failed, err = %d\n",
 		       -err);
 		goto out_kill;
 	}
diff --git a/arch/um/drivers/xterm_kern.c b/arch/um/drivers/xterm_kern.c
index 8011e51993d5..3971252cb1a6 100644
--- a/arch/um/drivers/xterm_kern.c
+++ b/arch/um/drivers/xterm_kern.c
@@ -21,12 +21,19 @@ struct xterm_wait {
 static irqreturn_t xterm_interrupt(int irq, void *data)
 {
 	struct xterm_wait *xterm = data;
-	int fd;
+	int fd = -1, n_fds = 1;
+	ssize_t ret;
 
-	fd = os_rcv_fd(xterm->fd, &xterm->pid);
-	if (fd == -EAGAIN)
+	ret = os_rcv_fd_msg(xterm->fd, &fd, n_fds,
+			    &xterm->pid, sizeof(xterm->pid));
+	if (ret == -EAGAIN)
 		return IRQ_NONE;
 
+	if (ret < 0)
+		fd = ret;
+	else if (ret != sizeof(xterm->pid))
+		fd = -EMSGSIZE;
+
 	xterm->new_fd = fd;
 	complete(&xterm->ready);