xref: /linux-tools/drivers/mremap/kernel-mremap-pid-patch-6.0.0.diff (revision 74ce4ce33d5b8318cee71b38976a25818e666ff3)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 8bbcccbc5565..797cc64fe182 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2721,6 +2721,7 @@ unsigned long randomize_stack_top(unsigned long stack_top);
 unsigned long randomize_page(unsigned long start, unsigned long range);

 extern unsigned long get_unmapped_area(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
+extern unsigned long get_unmapped_area2(struct mm_struct *mm, struct file *, unsigned long, unsigned long, unsigned long, unsigned long);

 extern unsigned long mmap_region(struct file *file, unsigned long addr,
 	unsigned long len, vm_flags_t vm_flags, unsigned long pgoff,
@@ -3474,5 +3475,7 @@ madvise_set_anon_name(struct mm_struct *mm, unsigned long start,
  * default, the flag is not set.
  */
 #define  ZAP_FLAG_DROP_MARKER        ((__force zap_flags_t) BIT(0))
+unsigned long mremap_task(struct task_struct *current_task, unsigned long addr,
+    unsigned long old_len, unsigned long new_len, unsigned long flags, unsigned long new_addr);

 #endif /* _LINUX_MM_H */
diff --git a/mm/mmap.c b/mm/mmap.c
index 6e447544f07d..b34fbb6a6776 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1798,6 +1798,50 @@ get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,

 EXPORT_SYMBOL(get_unmapped_area);

+unsigned long
+get_unmapped_area2(struct mm_struct *mm, struct file *file, unsigned long addr, unsigned long len,
+		unsigned long pgoff, unsigned long flags)
+{
+	unsigned long (*get_area)(struct file *, unsigned long,
+				  unsigned long, unsigned long, unsigned long);
+
+	unsigned long error = arch_mmap_check(addr, len, flags);
+	if (error)
+		return error;
+
+	/* Careful about overflows.. */
+	if (len > TASK_SIZE)
+		return -ENOMEM;
+
+	get_area = mm->get_unmapped_area;
+	if (file) {
+		if (file->f_op->get_unmapped_area)
+			get_area = file->f_op->get_unmapped_area;
+	} else if (flags & MAP_SHARED) {
+		/*
+		 * mmap_region() will call shmem_zero_setup() to create a file,
+		 * so use shmem's get_unmapped_area in case it can be huge.
+		 * do_mmap() will clear pgoff, so match alignment.
+		 */
+		pgoff = 0;
+		get_area = shmem_get_unmapped_area;
+	} else if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) {
+		/* Ensures that larger anonymous mappings are THP aligned. */
+		get_area = thp_get_unmapped_area;
+	}
+
+	addr = get_area(file, addr, len, pgoff, flags);
+	if (IS_ERR_VALUE(addr))
+		return addr;
+
+	if (addr > TASK_SIZE - len)
+		return -ENOMEM;
+	if (offset_in_page(addr))
+		return -EINVAL;
+
+	error = security_mmap_addr(addr);
+	return error ? error : addr;
+}
 /**
  * find_vma_intersection() - Look up the first VMA which intersects the interval
  * @mm: The process address space.
@@ -3308,8 +3352,8 @@ static int special_mapping_mremap(struct vm_area_struct *new_vma)
 {
 	struct vm_special_mapping *sm = new_vma->vm_private_data;

-	if (WARN_ON_ONCE(current->mm != new_vma->vm_mm))
-		return -EFAULT;
+	// if (WARN_ON_ONCE(current->mm != new_vma->vm_mm))
+	//	return -EFAULT;

 	if (sm->mremap)
 		return sm->mremap(sm, new_vma);
diff --git a/mm/mremap.c b/mm/mremap.c
index e465ffe279bb..01bba4bf97f6 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -724,10 +724,11 @@ static unsigned long move_vma(struct vm_area_struct *vma,
 	return new_addr;
 }

-static struct vm_area_struct *vma_to_resize(unsigned long addr,
+static struct vm_area_struct *vma_to_resize(struct mm_struct *mm,
+        unsigned long addr,
 	unsigned long old_len, unsigned long new_len, unsigned long flags)
 {
-	struct mm_struct *mm = current->mm;
+	// struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;
 	unsigned long pgoff;

@@ -778,13 +779,14 @@ static struct vm_area_struct *vma_to_resize(unsigned long addr,
 	return vma;
 }

-static unsigned long mremap_to(unsigned long addr, unsigned long old_len,
+static unsigned long mremap_to(struct mm_struct *mm,
+        unsigned long addr, unsigned long old_len,
 		unsigned long new_addr, unsigned long new_len, bool *locked,
 		unsigned long flags, struct vm_userfaultfd_ctx *uf,
 		struct list_head *uf_unmap_early,
 		struct list_head *uf_unmap)
 {
-	struct mm_struct *mm = current->mm;
+	// struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;
 	unsigned long ret = -EINVAL;
 	unsigned long map_flags = 0;
@@ -829,7 +831,7 @@ static unsigned long mremap_to(unsigned long addr, unsigned long old_len,
 		old_len = new_len;
 	}

-	vma = vma_to_resize(addr, old_len, new_len, flags);
+	vma = vma_to_resize(mm, addr, old_len, new_len, flags);
 	if (IS_ERR(vma)) {
 		ret = PTR_ERR(vma);
 		goto out;
@@ -848,7 +850,7 @@ static unsigned long mremap_to(unsigned long addr, unsigned long old_len,
 	if (vma->vm_flags & VM_MAYSHARE)
 		map_flags |= MAP_SHARED;

-	ret = get_unmapped_area(vma->vm_file, new_addr, new_len, vma->vm_pgoff +
+	ret = get_unmapped_area2(mm, vma->vm_file, new_addr, new_len, vma->vm_pgoff +
 				((addr - vma->vm_start) >> PAGE_SHIFT),
 				map_flags);
 	if (IS_ERR_VALUE(ret))
@@ -890,7 +892,13 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
 		unsigned long, new_len, unsigned long, flags,
 		unsigned long, new_addr)
 {
-	struct mm_struct *mm = current->mm;
+    return mremap_task(current, addr, old_len, new_len, flags, new_addr);
+}
+
+unsigned long mremap_task(struct task_struct *current_task, unsigned long addr,
+    unsigned long old_len, unsigned long new_len, unsigned long flags, unsigned long new_addr)
+{
+	struct mm_struct *mm = current_task->mm;
 	struct vm_area_struct *vma;
 	unsigned long ret = -EINVAL;
 	bool locked = false;
@@ -940,7 +948,7 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
 	if (!new_len)
 		return ret;

-	if (mmap_write_lock_killable(current->mm))
+	if (mmap_write_lock_killable(current_task->mm))
 		return -EINTR;
 	vma = vma_lookup(mm, addr);
 	if (!vma) {
@@ -969,7 +977,7 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
 	}

 	if (flags & (MREMAP_FIXED | MREMAP_DONTUNMAP)) {
-		ret = mremap_to(addr, old_len, new_addr, new_len,
+		ret = mremap_to(mm, addr, old_len, new_addr, new_len,
 				&locked, flags, &uf, &uf_unmap_early,
 				&uf_unmap);
 		goto out;
@@ -1002,7 +1010,7 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
 	/*
 	 * Ok, we need to grow..
 	 */
-	vma = vma_to_resize(addr, old_len, new_len, flags);
+	vma = vma_to_resize(mm, addr, old_len, new_len, flags);
 	if (IS_ERR(vma)) {
 		ret = PTR_ERR(vma);
 		goto out;
@@ -1079,9 +1087,9 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
 	if (offset_in_page(ret))
 		locked = false;
 	if (downgraded)
-		mmap_read_unlock(current->mm);
+		mmap_read_unlock(current_task->mm);
 	else
-		mmap_write_unlock(current->mm);
+		mmap_write_unlock(current_task->mm);
 	if (locked && new_len > old_len)
 		mm_populate(new_addr + old_len, new_len - old_len);
 	userfaultfd_unmap_complete(mm, &uf_unmap_early);
@@ -1089,3 +1097,4 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
 	userfaultfd_unmap_complete(mm, &uf_unmap);
 	return ret;
 }
+EXPORT_SYMBOL(mremap_task);