Update Linux to v5.4.148

Sourced from [1]

[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.4.148.tar.gz

Change-Id: Ib3d26c5ba9b022e2e03533005c4fed4d7c30b61b
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/arch/um/os-Linux/file.c b/arch/um/os-Linux/file.c
index 5133e3a..3996937 100644
--- a/arch/um/os-Linux/file.c
+++ b/arch/um/os-Linux/file.c
@@ -8,6 +8,7 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <signal.h>
+#include <linux/falloc.h>
 #include <sys/ioctl.h>
 #include <sys/mount.h>
 #include <sys/socket.h>
diff --git a/arch/um/os-Linux/irq.c b/arch/um/os-Linux/irq.c
index d508310..f1732c3 100644
--- a/arch/um/os-Linux/irq.c
+++ b/arch/um/os-Linux/irq.c
@@ -48,7 +48,7 @@
 int os_event_mask(int irq_type)
 {
 	if (irq_type == IRQ_READ)
-		return EPOLLIN | EPOLLPRI;
+		return EPOLLIN | EPOLLPRI | EPOLLERR | EPOLLHUP | EPOLLRDHUP;
 	if (irq_type == IRQ_WRITE)
 		return EPOLLOUT;
 	return 0;
diff --git a/arch/um/os-Linux/main.c b/arch/um/os-Linux/main.c
index 8014dfa..c8a42ec 100644
--- a/arch/um/os-Linux/main.c
+++ b/arch/um/os-Linux/main.c
@@ -170,7 +170,7 @@
 	 * that they won't be delivered after the exec, when
 	 * they are definitely not expected.
 	 */
-	unblock_signals_trace();
+	unblock_signals();
 
 	os_info("\n");
 	/* Reboot */
diff --git a/arch/um/os-Linux/umid.c b/arch/um/os-Linux/umid.c
index 44def53..ea5c60f 100644
--- a/arch/um/os-Linux/umid.c
+++ b/arch/um/os-Linux/umid.c
@@ -137,20 +137,13 @@
 {
 	char pid[sizeof("nnnnn\0")], *end, *file;
 	int dead, fd, p, n, err;
-	size_t filelen;
+	size_t filelen = strlen(dir) + sizeof("/pid") + 1;
 
-	err = asprintf(&file, "%s/pid", dir);
-	if (err < 0)
-		return 0;
+	file = malloc(filelen);
+	if (!file)
+		return -ENOMEM;
 
-	filelen = strlen(file);
-
-	n = snprintf(file, filelen, "%s/pid", dir);
-	if (n >= filelen) {
-		printk(UM_KERN_ERR "is_umdir_used - pid filename too long\n");
-		err = -E2BIG;
-		goto out;
-	}
+	snprintf(file, filelen, "%s/pid", dir);
 
 	dead = 0;
 	fd = open(file, O_RDONLY);