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authorLinus Torvalds <torvalds@linux-foundation.org>2017-09-01 10:36:22 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-09-01 10:36:22 -0700
commitbba2a5b8221850418846d62887d5de311df335f9 (patch)
tree129ade5d7f32fec65707a64a2d5ae19ca0167323 /arch
parenta1c516a60a702630347e27c7beb7f2f44ca7a8b5 (diff)
parent0fdd49ad1bb17457d119f8c3bc8ecdd0734eed9c (diff)
downloadlinux-bba2a5b8221850418846d62887d5de311df335f9.tar.gz
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull s390 fixes from Martin Schwidefsky:
 "Three more bug fixes for v4.13.

  The two memory management related fixes are quite new, they fix kernel
  crashes that can be triggered by user space.

  The third commit fixes a bug in the vfio ccw translation code"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/mm: fix BUG_ON in crst_table_upgrade
  s390/mm: fork vs. 5 level page tabel
  vfio: ccw: fix bad ptr math for TIC cda translation
Diffstat (limited to 'arch')
-rw-r--r--arch/s390/include/asm/mmu_context.h5
-rw-r--r--arch/s390/mm/mmap.c6
2 files changed, 9 insertions, 2 deletions
diff --git a/arch/s390/include/asm/mmu_context.h b/arch/s390/include/asm/mmu_context.h
index 4541ac44b35f..24bc41622a98 100644
--- a/arch/s390/include/asm/mmu_context.h
+++ b/arch/s390/include/asm/mmu_context.h
@@ -44,6 +44,11 @@ static inline int init_new_context(struct task_struct *tsk,
 		mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
 				   _ASCE_USER_BITS | _ASCE_TYPE_REGION3;
 		break;
+	case -PAGE_SIZE:
+		/* forked 5-level task, set new asce with new_mm->pgd */
+		mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
+			_ASCE_USER_BITS | _ASCE_TYPE_REGION1;
+		break;
 	case 1UL << 53:
 		/* forked 4-level task, set new asce with new mm->pgd */
 		mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c
index 2e10d2b8ad35..5bea139517a2 100644
--- a/arch/s390/mm/mmap.c
+++ b/arch/s390/mm/mmap.c
@@ -119,7 +119,8 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
 		return addr;
 
 check_asce_limit:
-	if (addr + len > current->mm->context.asce_limit) {
+	if (addr + len > current->mm->context.asce_limit &&
+	    addr + len <= TASK_SIZE) {
 		rc = crst_table_upgrade(mm, addr + len);
 		if (rc)
 			return (unsigned long) rc;
@@ -183,7 +184,8 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 	}
 
 check_asce_limit:
-	if (addr + len > current->mm->context.asce_limit) {
+	if (addr + len > current->mm->context.asce_limit &&
+	    addr + len <= TASK_SIZE) {
 		rc = crst_table_upgrade(mm, addr + len);
 		if (rc)
 			return (unsigned long) rc;