Merge tag 'v4.9.45' into v4.9-rt

This is the 4.9.45 stable release

6 files changed, 35 insertions, 51 deletions

diff --git a/mm/memblock.c b/mm/memblock.c
index 68849d0ead09..ccec42c12ba8 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -297,31 +297,27 @@ static void __init_memblock memblock_remove_region(struct memblock_type *type, u
 }
 
 #ifdef CONFIG_ARCH_DISCARD_MEMBLOCK
-
-phys_addr_t __init_memblock get_allocated_memblock_reserved_regions_info(
-					phys_addr_t *addr)
-{
-	if (memblock.reserved.regions == memblock_reserved_init_regions)
-		return 0;
-
-	*addr = __pa(memblock.reserved.regions);
-
-	return PAGE_ALIGN(sizeof(struct memblock_region) *
-			  memblock.reserved.max);
-}
-
-phys_addr_t __init_memblock get_allocated_memblock_memory_regions_info(
-					phys_addr_t *addr)
+/**
+ * Discard memory and reserved arrays if they were allocated
+ */
+void __init memblock_discard(void)
 {
-	if (memblock.memory.regions == memblock_memory_init_regions)
-		return 0;
+	phys_addr_t addr, size;
 
-	*addr = __pa(memblock.memory.regions);
+	if (memblock.reserved.regions != memblock_reserved_init_regions) {
+		addr = __pa(memblock.reserved.regions);
+		size = PAGE_ALIGN(sizeof(struct memblock_region) *
+				  memblock.reserved.max);
+		__memblock_free_late(addr, size);
+	}
 
-	return PAGE_ALIGN(sizeof(struct memblock_region) *
-			  memblock.memory.max);
+	if (memblock.memory.regions == memblock_memory_init_regions) {
+		addr = __pa(memblock.memory.regions);
+		size = PAGE_ALIGN(sizeof(struct memblock_region) *
+				  memblock.memory.max);
+		__memblock_free_late(addr, size);
+	}
 }
-
 #endif
 
 /**
diff --git a/mm/memory.c b/mm/memory.c
index 9bf3da0d0e14..d064caff9d7d 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3635,8 +3635,18 @@ int handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
 	 * further.
 	 */
 	if (unlikely((current->flags & PF_KTHREAD) && !(ret & VM_FAULT_ERROR)
-				&& test_bit(MMF_UNSTABLE, &vma->vm_mm->flags)))
+				&& test_bit(MMF_UNSTABLE, &vma->vm_mm->flags))) {
+
+		/*
+		 * We are going to enforce SIGBUS but the PF path might have
+		 * dropped the mmap_sem already so take it again so that
+		 * we do not break expectations of all arch specific PF paths
+		 * and g-u-p
+		 */
+		if (ret & VM_FAULT_RETRY)
+			down_read(&vma->vm_mm->mmap_sem);
 		ret = VM_FAULT_SIGBUS;
+	}
 
 	return ret;
 }
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 23471526d424..a8ab5e73dc61 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -926,11 +926,6 @@ static long do_get_mempolicy(int *policy, nodemask_t *nmask,
 		*policy |= (pol->flags & MPOL_MODE_FLAGS);
 	}
 
-	if (vma) {
-		up_read(&current->mm->mmap_sem);
-		vma = NULL;
-	}
-
 	err = 0;
 	if (nmask) {
 		if (mpol_store_user_nodemask(pol)) {
diff --git a/mm/migrate.c b/mm/migrate.c
index 6850f62998cd..821623fc7091 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -40,6 +40,7 @@
 #include <linux/mmu_notifier.h>
 #include <linux/page_idle.h>
 #include <linux/page_owner.h>
+#include <linux/ptrace.h>
 
 #include <asm/tlbflush.h>
 
@@ -1663,7 +1664,6 @@ SYSCALL_DEFINE6(move_pages, pid_t, pid, unsigned long, nr_pages,
 		const int __user *, nodes,
 		int __user *, status, int, flags)
 {
-	const struct cred *cred = current_cred(), *tcred;
 	struct task_struct *task;
 	struct mm_struct *mm;
 	int err;
@@ -1687,14 +1687,9 @@ SYSCALL_DEFINE6(move_pages, pid_t, pid, unsigned long, nr_pages,
 
 	/*
 	 * Check if this process has the right to modify the specified
-	 * process. The right exists if the process has administrative
-	 * capabilities, superuser privileges or the same
-	 * userid as the target process.
+	 * process. Use the regular "ptrace_may_access()" checks.
 	 */
-	tcred = __task_cred(task);
-	if (!uid_eq(cred->euid, tcred->suid) && !uid_eq(cred->euid, tcred->uid) &&
-	    !uid_eq(cred->uid,  tcred->suid) && !uid_eq(cred->uid,  tcred->uid) &&
-	    !capable(CAP_SYS_NICE)) {
+	if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) {
 		rcu_read_unlock();
 		err = -EPERM;
 		goto out;
diff --git a/mm/nobootmem.c b/mm/nobootmem.c
index 487dad610731..ab998125f04d 100644
--- a/mm/nobootmem.c
+++ b/mm/nobootmem.c
@@ -146,22 +146,6 @@ static unsigned long __init free_low_memory_core_early(void)
 				NULL)
 		count += __free_memory_core(start, end);
 
-#ifdef CONFIG_ARCH_DISCARD_MEMBLOCK
-	{
-		phys_addr_t size;
-
-		/* Free memblock.reserved array if it was allocated */
-		size = get_allocated_memblock_reserved_regions_info(&start);
-		if (size)
-			count += __free_memory_core(start, start + size);
-
-		/* Free memblock.memory array if it was allocated */
-		size = get_allocated_memblock_memory_regions_info(&start);
-		if (size)
-			count += __free_memory_core(start, start + size);
-	}
-#endif
-
 	return count;
 }
 
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 4adab199b8f2..a63aa41760af 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1626,6 +1626,10 @@ void __init page_alloc_init_late(void)
 	/* Reinit limits that are based on free pages after the kernel is up */
 	files_maxfiles_init();
 #endif
+#ifdef CONFIG_ARCH_DISCARD_MEMBLOCK
+	/* Discard memblock private memory */
+	memblock_discard();
+#endif
 
 	for_each_populated_zone(zone)
 		set_zone_contiguous(zone);