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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2012-07-26 08:53:06 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2012-07-26 16:24:14 +0200
commit0f6f281b731d20bfe75c13f85d33f3f05b440222 (patch)
tree0f8c23d3fca50dd2830ddc978501cd45a0057f45 /arch/s390/mm/mmap.c
parent8143adafd2d00b13f1db96ce06b6bf479e0bfe5b (diff)
s390/mm: downgrade page table after fork of a 31 bit process
The downgrade of the 4 level page table created by init_new_context is currently done only in start_thread31. If a 31 bit process forks the new mm uses a 4 level page table, including the task size of 2<<42 that goes along with it. This is incorrect as now a 31 bit process can map memory beyond 2GB. Define arch_dup_mmap to do the downgrade after fork. Cc: stable@vger.kernel.org Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/mm/mmap.c')
-rw-r--r--arch/s390/mm/mmap.c12
1 files changed, 10 insertions, 2 deletions
diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c
index 573384256c5c..c59a5efa58b1 100644
--- a/arch/s390/mm/mmap.c
+++ b/arch/s390/mm/mmap.c
@@ -103,9 +103,15 @@ void arch_pick_mmap_layout(struct mm_struct *mm)
int s390_mmap_check(unsigned long addr, unsigned long len)
{
+ int rc;
+
if (!is_compat_task() &&
- len >= TASK_SIZE && TASK_SIZE < (1UL << 53))
- return crst_table_upgrade(current->mm, 1UL << 53);
+ len >= TASK_SIZE && TASK_SIZE < (1UL << 53)) {
+ rc = crst_table_upgrade(current->mm, 1UL << 53);
+ if (rc)
+ return rc;
+ update_mm(current->mm, current);
+ }
return 0;
}
@@ -125,6 +131,7 @@ s390_get_unmapped_area(struct file *filp, unsigned long addr,
rc = crst_table_upgrade(mm, 1UL << 53);
if (rc)
return (unsigned long) rc;
+ update_mm(mm, current);
area = arch_get_unmapped_area(filp, addr, len, pgoff, flags);
}
return area;
@@ -147,6 +154,7 @@ s390_get_unmapped_area_topdown(struct file *filp, const unsigned long addr,
rc = crst_table_upgrade(mm, 1UL << 53);
if (rc)
return (unsigned long) rc;
+ update_mm(mm, current);
area = arch_get_unmapped_area_topdown(filp, addr, len,
pgoff, flags);
}