Merge tag 'for-linus-5.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml

Pull UML updates from Richard Weinberger:

 - Improve support for non-glibc systems

 - Vector: Add support for scripting and dynamic tap devices

 - Various fixes for the vector networking driver

 - Various fixes for time travel mode

* tag 'for-linus-5.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
  um: vector: Add dynamic tap interfaces and scripting
  um: Clean up stacktrace dump
  um: Fix incorrect assumptions about max pid length
  um: Remove dead usage of TIF_IA32
  um: Remove redundant NULL check
  um: change sigio_spinlock to a mutex
  um: time-travel: Return the sequence number in ACK messages
  um: time-travel: Fix IRQ handling in time_travel_handle_message()
  um: Allow static linking for non-glibc implementations
  um: Some fixes to build UML with musl
  um: vector: Use GFP_ATOMIC under spin lock
  um: Fix null pointer dereference in vector_user_bpf

3 files changed, 14 insertions, 11 deletions

diff --git a/arch/um/kernel/sigio.c b/arch/um/kernel/sigio.c
index 10c99e058fca..d1cffc2a7f21 100644
--- a/arch/um/kernel/sigio.c
+++ b/arch/um/kernel/sigio.c
@@ -35,14 +35,14 @@ int write_sigio_irq(int fd)
 }
 
 /* These are called from os-Linux/sigio.c to protect its pollfds arrays. */
-static DEFINE_SPINLOCK(sigio_spinlock);
+static DEFINE_MUTEX(sigio_mutex);
 
 void sigio_lock(void)
 {
-	spin_lock(&sigio_spinlock);
+	mutex_lock(&sigio_mutex);
 }
 
 void sigio_unlock(void)
 {
-	spin_unlock(&sigio_spinlock);
+	mutex_unlock(&sigio_mutex);
 }
diff --git a/arch/um/kernel/sysrq.c b/arch/um/kernel/sysrq.c
index acbc879d2773..7452f70d50d0 100644
--- a/arch/um/kernel/sysrq.c
+++ b/arch/um/kernel/sysrq.c
@@ -47,12 +47,10 @@ void show_stack(struct task_struct *task, unsigned long *stack,
 		if (kstack_end(stack))
 			break;
 		if (i && ((i % STACKSLOTS_PER_LINE) == 0))
-			printk("%s\n", loglvl);
+			pr_cont("\n");
 		pr_cont(" %08lx", *stack++);
 	}
-	printk("%s\n", loglvl);
 
 	printk("%sCall Trace:\n", loglvl);
 	dump_trace(current, &stackops, (void *)loglvl);
-	printk("%s\n", loglvl);
 }
diff --git a/arch/um/kernel/time.c b/arch/um/kernel/time.c
index 25eaa6a0c658..3d109ff3309b 100644
--- a/arch/um/kernel/time.c
+++ b/arch/um/kernel/time.c
@@ -70,13 +70,17 @@ static void time_travel_handle_message(struct um_timetravel_msg *msg,
 	 * read of the message and write of the ACK.
 	 */
 	if (mode != TTMH_READ) {
+		bool disabled = irqs_disabled();
+
+		BUG_ON(mode == TTMH_IDLE && !disabled);
+
+		if (disabled)
+			local_irq_enable();
 		while (os_poll(1, &time_travel_ext_fd) != 0) {
-			if (mode == TTMH_IDLE) {
-				BUG_ON(!irqs_disabled());
-				local_irq_enable();
-				local_irq_disable();
-			}
+			/* nothing */
 		}
+		if (disabled)
+			local_irq_disable();
 	}
 
 	ret = os_read_file(time_travel_ext_fd, msg, sizeof(*msg));
@@ -102,6 +106,7 @@ static void time_travel_handle_message(struct um_timetravel_msg *msg,
 		break;
 	}
 
+	resp.seq = msg->seq;
 	os_write_file(time_travel_ext_fd, &resp, sizeof(resp));
 }