Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Alexei Starovoitov says:

====================
pull-request: bpf-next 2020-07-14

The following pull-request contains BPF updates for your *net-next* tree.

We've added 21 non-merge commits during the last 1 day(s) which contain
a total of 20 files changed, 308 insertions(+), 279 deletions(-).

The main changes are:

1) Fix selftests/bpf build, from Alexei.

2) Fix resolve_btfids build issues, from Jiri.

3) Pull usermode-driver-cleanup set, from Eric.

4) Two minor fixes to bpfilter, from Alexei and Masahiro.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 40 insertions, 33 deletions

diff --git a/net/bpfilter/Kconfig b/net/bpfilter/Kconfig
index 84015ef3ee27..73d0b12789f1 100644
--- a/net/bpfilter/Kconfig
+++ b/net/bpfilter/Kconfig
@@ -9,12 +9,14 @@ menuconfig BPFILTER
 if BPFILTER
 config BPFILTER_UMH
 	tristate "bpfilter kernel module with user mode helper"
-	depends on CC_CAN_LINK_STATIC
+	depends on CC_CAN_LINK
+	depends on m || CC_CAN_LINK_STATIC
 	default m
 	help
 	  This builds bpfilter kernel module with embedded user mode helper
 
-	  Note: your toolchain must support building static binaries, since
-	  rootfs isn't mounted at the time when __init functions are called
-	  and do_execv won't be able to find the elf interpreter.
+	  Note: To compile this as built-in, your toolchain must support
+	  building static binaries, since rootfs isn't mounted at the time
+	  when __init functions are called and do_execv won't be able to find
+	  the elf interpreter.
 endif
diff --git a/net/bpfilter/Makefile b/net/bpfilter/Makefile
index f23b53294fba..cdac82b8c53a 100644
--- a/net/bpfilter/Makefile
+++ b/net/bpfilter/Makefile
@@ -7,10 +7,12 @@ userprogs := bpfilter_umh
 bpfilter_umh-objs := main.o
 userccflags += -I $(srctree)/tools/include/ -I $(srctree)/tools/include/uapi
 
+ifeq ($(CONFIG_BPFILTER_UMH), y)
 # builtin bpfilter_umh should be linked with -static
 # since rootfs isn't mounted at the time of __init
 # function is called and do_execv won't find elf interpreter
 userldflags += -static
+endif
 
 $(obj)/bpfilter_umh_blob.o: $(obj)/bpfilter_umh
 
diff --git a/net/bpfilter/bpfilter_kern.c b/net/bpfilter/bpfilter_kern.c
index 1905e01c3aa9..2c31e82cb953 100644
--- a/net/bpfilter/bpfilter_kern.c
+++ b/net/bpfilter/bpfilter_kern.c
@@ -15,15 +15,13 @@ extern char bpfilter_umh_end;
 
 static void shutdown_umh(void)
 {
-	struct task_struct *tsk;
+	struct umd_info *info = &bpfilter_ops.info;
+	struct pid *tgid = info->tgid;
 
-	if (bpfilter_ops.stop)
-		return;
-
-	tsk = get_pid_task(find_vpid(bpfilter_ops.info.pid), PIDTYPE_PID);
-	if (tsk) {
-		send_sig(SIGKILL, tsk, 1);
-		put_task_struct(tsk);
+	if (tgid) {
+		kill_pid(tgid, SIGKILL, 1);
+		wait_event(tgid->wait_pidfd, thread_group_exited(tgid));
+		bpfilter_umh_cleanup(info);
 	}
 }
 
@@ -48,8 +46,9 @@ static int __bpfilter_process_sockopt(struct sock *sk, int optname,
 	req.cmd = optname;
 	req.addr = (long __force __user)optval;
 	req.len = optlen;
-	if (!bpfilter_ops.info.pid)
+	if (!bpfilter_ops.info.tgid)
 		goto out;
+	pos = 0;
 	n = kernel_write(bpfilter_ops.info.pipe_to_umh, &req, sizeof(req),
 			   &pos);
 	if (n != sizeof(req)) {
@@ -77,13 +76,10 @@ static int start_umh(void)
 	int err;
 
 	/* fork usermode process */
-	err = fork_usermode_blob(&bpfilter_umh_start,
-				 &bpfilter_umh_end - &bpfilter_umh_start,
-				 &bpfilter_ops.info);
+	err = fork_usermode_driver(&bpfilter_ops.info);
 	if (err)
 		return err;
-	bpfilter_ops.stop = false;
-	pr_info("Loaded bpfilter_umh pid %d\n", bpfilter_ops.info.pid);
+	pr_info("Loaded bpfilter_umh pid %d\n", pid_nr(bpfilter_ops.info.tgid));
 
 	/* health check that usermode process started correctly */
 	if (__bpfilter_process_sockopt(NULL, 0, NULL, 0, 0) != 0) {
@@ -98,18 +94,21 @@ static int __init load_umh(void)
 {
 	int err;
 
+	err = umd_load_blob(&bpfilter_ops.info,
+			    &bpfilter_umh_start,
+			    &bpfilter_umh_end - &bpfilter_umh_start);
+	if (err)
+		return err;
+
 	mutex_lock(&bpfilter_ops.lock);
-	if (!bpfilter_ops.stop) {
-		err = -EFAULT;
-		goto out;
-	}
 	err = start_umh();
 	if (!err && IS_ENABLED(CONFIG_INET)) {
 		bpfilter_ops.sockopt = &__bpfilter_process_sockopt;
 		bpfilter_ops.start = &start_umh;
 	}
-out:
 	mutex_unlock(&bpfilter_ops.lock);
+	if (err)
+		umd_unload_blob(&bpfilter_ops.info);
 	return err;
 }
 
@@ -122,6 +121,8 @@ static void __exit fini_umh(void)
 		bpfilter_ops.sockopt = NULL;
 	}
 	mutex_unlock(&bpfilter_ops.lock);
+
+	umd_unload_blob(&bpfilter_ops.info);
 }
 module_init(load_umh);
 module_exit(fini_umh);
diff --git a/net/bpfilter/bpfilter_umh_blob.S b/net/bpfilter/bpfilter_umh_blob.S
index 9ea6100dca87..40311d10d2f2 100644
--- a/net/bpfilter/bpfilter_umh_blob.S
+++ b/net/bpfilter/bpfilter_umh_blob.S
@@ -1,5 +1,5 @@
 /* SPDX-License-Identifier: GPL-2.0 */
-	.section .rodata, "a"
+	.section .init.rodata, "a"
 	.global bpfilter_umh_start
 bpfilter_umh_start:
 	.incbin "net/bpfilter/bpfilter_umh"
diff --git a/net/ipv4/bpfilter/sockopt.c b/net/ipv4/bpfilter/sockopt.c
index 0480918bfc7c..9063c6767d34 100644
--- a/net/ipv4/bpfilter/sockopt.c
+++ b/net/ipv4/bpfilter/sockopt.c
@@ -12,15 +12,14 @@
 struct bpfilter_umh_ops bpfilter_ops;
 EXPORT_SYMBOL_GPL(bpfilter_ops);
 
-static void bpfilter_umh_cleanup(struct umh_info *info)
+void bpfilter_umh_cleanup(struct umd_info *info)
 {
-	mutex_lock(&bpfilter_ops.lock);
-	bpfilter_ops.stop = true;
 	fput(info->pipe_to_umh);
 	fput(info->pipe_from_umh);
-	info->pid = 0;
-	mutex_unlock(&bpfilter_ops.lock);
+	put_pid(info->tgid);
+	info->tgid = NULL;
 }
+EXPORT_SYMBOL_GPL(bpfilter_umh_cleanup);
 
 static int bpfilter_mbox_request(struct sock *sk, int optname,
 				 char __user *optval,
@@ -38,7 +37,11 @@ static int bpfilter_mbox_request(struct sock *sk, int optname,
 			goto out;
 		}
 	}
-	if (bpfilter_ops.stop) {
+	if (bpfilter_ops.info.tgid &&
+	    thread_group_exited(bpfilter_ops.info.tgid))
+		bpfilter_umh_cleanup(&bpfilter_ops.info);
+
+	if (!bpfilter_ops.info.tgid) {
 		err = bpfilter_ops.start();
 		if (err)
 			goto out;
@@ -69,9 +72,8 @@ int bpfilter_ip_get_sockopt(struct sock *sk, int optname, char __user *optval,
 static int __init bpfilter_sockopt_init(void)
 {
 	mutex_init(&bpfilter_ops.lock);
-	bpfilter_ops.stop = true;
-	bpfilter_ops.info.cmdline = "bpfilter_umh";
-	bpfilter_ops.info.cleanup = &bpfilter_umh_cleanup;
+	bpfilter_ops.info.tgid = NULL;
+	bpfilter_ops.info.driver_name = "bpfilter_umh";
 
 	return 0;
 }