Merge branch 'akpm' (patches from Andrew)

Merge more updates from Andrew Morton:
 "Various misc subsystems, before getting into the post-linux-next
  material.

  41 patches.

  Subsystems affected by this patch series: procfs, misc, core-kernel,
  lib, checkpatch, init, pipe, minix, fat, cgroups, kexec, kdump,
  taskstats, panic, kcov, resource, and ubsan"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (41 commits)
  Revert "ubsan, kcsan: Don't combine sanitizer with kcov on clang"
  kernel/resource: fix kfree() of bootmem memory again
  kcov: properly handle subsequent mmap calls
  kcov: split ioctl handling into locked and unlocked parts
  panic: move panic_print before kmsg dumpers
  panic: add option to dump all CPUs backtraces in panic_print
  docs: sysctl/kernel: add missing bit to panic_print
  taskstats: remove unneeded dead assignment
  kasan: no need to unset panic_on_warn in end_report()
  ubsan: no need to unset panic_on_warn in ubsan_epilogue()
  panic: unset panic_on_warn inside panic()
  docs: kdump: add scp example to write out the dump file
  docs: kdump: update description about sysfs file system support
  arm64: mm: use IS_ENABLED(CONFIG_KEXEC_CORE) instead of #ifdef
  x86/setup: use IS_ENABLED(CONFIG_KEXEC_CORE) instead of #ifdef
  riscv: mm: init: use IS_ENABLED(CONFIG_KEXEC_CORE) instead of #ifdef
  kexec: make crashk_res, crashk_low_res and crash_notes symbols always visible
  cgroup: use irqsave in cgroup_rstat_flush_locked().
  fat: use pointer to simple type in put_user()
  minix: fix bug when opening a file with O_DIRECT
  ...

1 files changed, 50 insertions, 48 deletions

diff --git a/kernel/kcov.c b/kernel/kcov.c
index 36ca640c4f8e..475524bd900a 100644
--- a/kernel/kcov.c
+++ b/kernel/kcov.c
@@ -459,37 +459,28 @@ void kcov_task_exit(struct task_struct *t)
 static int kcov_mmap(struct file *filep, struct vm_area_struct *vma)
 {
 	int res = 0;
-	void *area;
 	struct kcov *kcov = vma->vm_file->private_data;
 	unsigned long size, off;
 	struct page *page;
 	unsigned long flags;
 
-	area = vmalloc_user(vma->vm_end - vma->vm_start);
-	if (!area)
-		return -ENOMEM;
-
 	spin_lock_irqsave(&kcov->lock, flags);
 	size = kcov->size * sizeof(unsigned long);
-	if (kcov->mode != KCOV_MODE_INIT || vma->vm_pgoff != 0 ||
+	if (kcov->area == NULL || vma->vm_pgoff != 0 ||
 	    vma->vm_end - vma->vm_start != size) {
 		res = -EINVAL;
 		goto exit;
 	}
-	if (!kcov->area) {
-		kcov->area = area;
-		vma->vm_flags |= VM_DONTEXPAND;
-		spin_unlock_irqrestore(&kcov->lock, flags);
-		for (off = 0; off < size; off += PAGE_SIZE) {
-			page = vmalloc_to_page(kcov->area + off);
-			if (vm_insert_page(vma, vma->vm_start + off, page))
-				WARN_ONCE(1, "vm_insert_page() failed");
-		}
-		return 0;
+	spin_unlock_irqrestore(&kcov->lock, flags);
+	vma->vm_flags |= VM_DONTEXPAND;
+	for (off = 0; off < size; off += PAGE_SIZE) {
+		page = vmalloc_to_page(kcov->area + off);
+		if (vm_insert_page(vma, vma->vm_start + off, page))
+			WARN_ONCE(1, "vm_insert_page() failed");
 	}
+	return 0;
 exit:
 	spin_unlock_irqrestore(&kcov->lock, flags);
-	vfree(area);
 	return res;
 }
 
@@ -564,31 +555,12 @@ static int kcov_ioctl_locked(struct kcov *kcov, unsigned int cmd,
 			     unsigned long arg)
 {
 	struct task_struct *t;
-	unsigned long size, unused;
+	unsigned long flags, unused;
 	int mode, i;
 	struct kcov_remote_arg *remote_arg;
 	struct kcov_remote *remote;
-	unsigned long flags;
 
 	switch (cmd) {
-	case KCOV_INIT_TRACE:
-		/*
-		 * Enable kcov in trace mode and setup buffer size.
-		 * Must happen before anything else.
-		 */
-		if (kcov->mode != KCOV_MODE_DISABLED)
-			return -EBUSY;
-		/*
-		 * Size must be at least 2 to hold current position and one PC.
-		 * Later we allocate size * sizeof(unsigned long) memory,
-		 * that must not overflow.
-		 */
-		size = arg;
-		if (size < 2 || size > INT_MAX / sizeof(unsigned long))
-			return -EINVAL;
-		kcov->size = size;
-		kcov->mode = KCOV_MODE_INIT;
-		return 0;
 	case KCOV_ENABLE:
 		/*
 		 * Enable coverage for the current task.
@@ -692,9 +664,37 @@ static long kcov_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
 	struct kcov_remote_arg *remote_arg = NULL;
 	unsigned int remote_num_handles;
 	unsigned long remote_arg_size;
-	unsigned long flags;
+	unsigned long size, flags;
+	void *area;
 
-	if (cmd == KCOV_REMOTE_ENABLE) {
+	kcov = filep->private_data;
+	switch (cmd) {
+	case KCOV_INIT_TRACE:
+		/*
+		 * Enable kcov in trace mode and setup buffer size.
+		 * Must happen before anything else.
+		 *
+		 * First check the size argument - it must be at least 2
+		 * to hold the current position and one PC.
+		 */
+		size = arg;
+		if (size < 2 || size > INT_MAX / sizeof(unsigned long))
+			return -EINVAL;
+		area = vmalloc_user(size * sizeof(unsigned long));
+		if (area == NULL)
+			return -ENOMEM;
+		spin_lock_irqsave(&kcov->lock, flags);
+		if (kcov->mode != KCOV_MODE_DISABLED) {
+			spin_unlock_irqrestore(&kcov->lock, flags);
+			vfree(area);
+			return -EBUSY;
+		}
+		kcov->area = area;
+		kcov->size = size;
+		kcov->mode = KCOV_MODE_INIT;
+		spin_unlock_irqrestore(&kcov->lock, flags);
+		return 0;
+	case KCOV_REMOTE_ENABLE:
 		if (get_user(remote_num_handles, (unsigned __user *)(arg +
 				offsetof(struct kcov_remote_arg, num_handles))))
 			return -EFAULT;
@@ -710,16 +710,18 @@ static long kcov_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
 			return -EINVAL;
 		}
 		arg = (unsigned long)remote_arg;
+		fallthrough;
+	default:
+		/*
+		 * All other commands can be normally executed under a spin lock, so we
+		 * obtain and release it here in order to simplify kcov_ioctl_locked().
+		 */
+		spin_lock_irqsave(&kcov->lock, flags);
+		res = kcov_ioctl_locked(kcov, cmd, arg);
+		spin_unlock_irqrestore(&kcov->lock, flags);
+		kfree(remote_arg);
+		return res;
 	}
-
-	kcov = filep->private_data;
-	spin_lock_irqsave(&kcov->lock, flags);
-	res = kcov_ioctl_locked(kcov, cmd, arg);
-	spin_unlock_irqrestore(&kcov->lock, flags);
-
-	kfree(remote_arg);
-
-	return res;
 }
 
 static const struct file_operations kcov_fops = {