[PATCH v2 4/5] powerpc/64s/radix: Fix 128TB-512TB virtual address boundary case allocation

Nicholas Piggin npiggin at gmail.com
Fri Nov 10 04:27:39 AEDT 2017


Radix VA space allocations test addresses against mm->task_size which is
512TB, even in cases where the intention is to limit allocation to below
128TB.

This results in mmap with a hint address below 128TB but address + length
above 128TB succeeding when it should fail (as hash does after the
previous patch).

Set the high address limit to be considered up front, and base subsequent
allocation checks on that consistently.

Cc: "Aneesh Kumar K.V" <aneesh.kumar at linux.vnet.ibm.com>
Fixes: f4ea6dcb08 ("powerpc/mm: Enable mappings above 128TB")
Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
---
 arch/powerpc/mm/hugetlbpage-radix.c | 26 ++++++++++++------
 arch/powerpc/mm/mmap.c              | 55 ++++++++++++++++++++++---------------
 2 files changed, 50 insertions(+), 31 deletions(-)

diff --git a/arch/powerpc/mm/hugetlbpage-radix.c b/arch/powerpc/mm/hugetlbpage-radix.c
index 558e9d3891bf..bd022d16745c 100644
--- a/arch/powerpc/mm/hugetlbpage-radix.c
+++ b/arch/powerpc/mm/hugetlbpage-radix.c
@@ -49,17 +49,28 @@ radix__hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;
 	struct hstate *h = hstate_file(file);
+	int fixed = (flags & MAP_FIXED);
+	unsigned long high_limit;
 	struct vm_unmapped_area_info info;
 
-	if (unlikely(addr > mm->context.addr_limit && addr < TASK_SIZE))
-		mm->context.addr_limit = TASK_SIZE;
+	high_limit = DEFAULT_MAP_WINDOW;
+	if (addr >= high_limit || (fixed && (addr + len > high_limit)))
+		high_limit = TASK_SIZE;
 
 	if (len & ~huge_page_mask(h))
 		return -EINVAL;
-	if (len > mm->task_size)
+	if (len > high_limit)
 		return -ENOMEM;
+	if (fixed) {
+		if (addr > high_limit - len)
+			return -ENOMEM;
+	}
 
-	if (flags & MAP_FIXED) {
+	if (unlikely(addr > mm->context.addr_limit &&
+		     mm->context.addr_limit != TASK_SIZE))
+		mm->context.addr_limit = TASK_SIZE;
+
+	if (fixed) {
 		if (prepare_hugepage_range(file, addr, len))
 			return -EINVAL;
 		return addr;
@@ -68,7 +79,7 @@ radix__hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 	if (addr) {
 		addr = ALIGN(addr, huge_page_size(h));
 		vma = find_vma(mm, addr);
-		if (mm->task_size - len >= addr &&
+		if (high_limit - len >= addr &&
 		    (!vma || addr + len <= vm_start_gap(vma)))
 			return addr;
 	}
@@ -79,12 +90,9 @@ radix__hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
 	info.length = len;
 	info.low_limit = PAGE_SIZE;
-	info.high_limit = current->mm->mmap_base;
+	info.high_limit = mm->mmap_base + (high_limit - DEFAULT_MAP_WINDOW);
 	info.align_mask = PAGE_MASK & ~huge_page_mask(h);
 	info.align_offset = 0;
 
-	if (addr > DEFAULT_MAP_WINDOW)
-		info.high_limit += mm->context.addr_limit - DEFAULT_MAP_WINDOW;
-
 	return vm_unmapped_area(&info);
 }
diff --git a/arch/powerpc/mm/mmap.c b/arch/powerpc/mm/mmap.c
index 5d78b193fec4..6d476a7b5611 100644
--- a/arch/powerpc/mm/mmap.c
+++ b/arch/powerpc/mm/mmap.c
@@ -106,22 +106,32 @@ radix__arch_get_unmapped_area(struct file *filp, unsigned long addr,
 {
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;
+	int fixed = (flags & MAP_FIXED);
+	unsigned long high_limit;
 	struct vm_unmapped_area_info info;
 
+	high_limit = DEFAULT_MAP_WINDOW;
+	if (addr >= high_limit || (fixed && (addr + len > high_limit)))
+		high_limit = TASK_SIZE;
+
+	if (len > high_limit)
+		return -ENOMEM;
+	if (fixed) {
+		if (addr > high_limit - len)
+			return -ENOMEM;
+	}
+
 	if (unlikely(addr > mm->context.addr_limit &&
 		     mm->context.addr_limit != TASK_SIZE))
 		mm->context.addr_limit = TASK_SIZE;
 
-	if (len > mm->task_size - mmap_min_addr)
-		return -ENOMEM;
-
-	if (flags & MAP_FIXED)
+	if (fixed)
 		return addr;
 
 	if (addr) {
 		addr = PAGE_ALIGN(addr);
 		vma = find_vma(mm, addr);
-		if (mm->task_size - len >= addr && addr >= mmap_min_addr &&
+		if (high_limit - len >= addr && addr >= mmap_min_addr &&
 		    (!vma || addr + len <= vm_start_gap(vma)))
 			return addr;
 	}
@@ -129,13 +139,9 @@ radix__arch_get_unmapped_area(struct file *filp, unsigned long addr,
 	info.flags = 0;
 	info.length = len;
 	info.low_limit = mm->mmap_base;
+	info.high_limit = high_limit;
 	info.align_mask = 0;
 
-	if (unlikely(addr > DEFAULT_MAP_WINDOW))
-		info.high_limit = mm->context.addr_limit;
-	else
-		info.high_limit = DEFAULT_MAP_WINDOW;
-
 	return vm_unmapped_area(&info);
 }
 
@@ -149,37 +155,42 @@ radix__arch_get_unmapped_area_topdown(struct file *filp,
 	struct vm_area_struct *vma;
 	struct mm_struct *mm = current->mm;
 	unsigned long addr = addr0;
+	int fixed = (flags & MAP_FIXED);
+	unsigned long high_limit;
 	struct vm_unmapped_area_info info;
 
+	high_limit = DEFAULT_MAP_WINDOW;
+	if (addr >= high_limit || (fixed && (addr + len > high_limit)))
+		high_limit = TASK_SIZE;
+
+	if (len > high_limit)
+		return -ENOMEM;
+	if (fixed) {
+		if (addr > high_limit - len)
+			return -ENOMEM;
+	}
+
 	if (unlikely(addr > mm->context.addr_limit &&
 		     mm->context.addr_limit != TASK_SIZE))
 		mm->context.addr_limit = TASK_SIZE;
 
-	/* requested length too big for entire address space */
-	if (len > mm->task_size - mmap_min_addr)
-		return -ENOMEM;
-
-	if (flags & MAP_FIXED)
+	if (fixed)
 		return addr;
 
-	/* requesting a specific address */
 	if (addr) {
 		addr = PAGE_ALIGN(addr);
 		vma = find_vma(mm, addr);
-		if (mm->task_size - len >= addr && addr >= mmap_min_addr &&
-				(!vma || addr + len <= vm_start_gap(vma)))
+		if (high_limit - len >= addr && addr >= mmap_min_addr &&
+		    (!vma || addr + len <= vm_start_gap(vma)))
 			return addr;
 	}
 
 	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
 	info.length = len;
 	info.low_limit = max(PAGE_SIZE, mmap_min_addr);
-	info.high_limit = mm->mmap_base;
+	info.high_limit = mm->mmap_base + (high_limit - DEFAULT_MAP_WINDOW);
 	info.align_mask = 0;
 
-	if (addr > DEFAULT_MAP_WINDOW)
-		info.high_limit += mm->context.addr_limit - DEFAULT_MAP_WINDOW;
-
 	addr = vm_unmapped_area(&info);
 	if (!(addr & ~PAGE_MASK))
 		return addr;
-- 
2.15.0



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