The patch titled
Subject: mm/mremap: for MREMAP_DONTUNMAP check security_vm_enough_memory_mm()
has been removed from the -mm tree. Its filename was
mm-mremap-for-mremap_dontunmap-check-security_vm_enough_memory_mm.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Dmitry Safonov <dima@xxxxxxxxxx>
Subject: mm/mremap: for MREMAP_DONTUNMAP check security_vm_enough_memory_mm()
Currently memory is accounted post-mremap() with MREMAP_DONTUNMAP, which
may break overcommit policy. So, check if there's enough memory before
doing actual VMA copy.
Don't unset VM_ACCOUNT on MREMAP_DONTUNMAP. By semantics, such mremap()
is actually a memory allocation. That also simplifies the error-path a
little.
Also, as it's memory allocation on success don't reset hiwater_vm value.
Link: https://lkml.kernel.org/r/20201013013416.390574-3-dima@xxxxxxxxxx
Fixes: commit e346b3813067 ("mm/mremap: add MREMAP_DONTUNMAP to mremap()")
Signed-off-by: Dmitry Safonov <dima@xxxxxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Brian Geffon <bgeffon@xxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Dave Jiang <dave.jiang@xxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Ralph Campbell <rcampbell@xxxxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxx>
Cc: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vishal Verma <vishal.l.verma@xxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mremap.c | 36 +++++++++++++-----------------------
1 file changed, 13 insertions(+), 23 deletions(-)
--- a/mm/mremap.c~mm-mremap-for-mremap_dontunmap-check-security_vm_enough_memory_mm
+++ a/mm/mremap.c
@@ -515,11 +515,19 @@ static unsigned long move_vma(struct vm_
if (err)
return err;
+ if (unlikely(flags & MREMAP_DONTUNMAP && vm_flags & VM_ACCOUNT)) {
+ if (security_vm_enough_memory_mm(mm, new_len >> PAGE_SHIFT))
+ return -ENOMEM;
+ }
+
new_pgoff = vma->vm_pgoff + ((old_addr - vma->vm_start) >> PAGE_SHIFT);
new_vma = copy_vma(&vma, new_addr, new_len, new_pgoff,
&need_rmap_locks);
- if (!new_vma)
+ if (!new_vma) {
+ if (unlikely(flags & MREMAP_DONTUNMAP && vm_flags & VM_ACCOUNT))
+ vm_unacct_memory(new_len >> PAGE_SHIFT);
return -ENOMEM;
+ }
moved_len = move_page_tables(vma, old_addr, new_vma, new_addr, old_len,
need_rmap_locks);
@@ -548,7 +556,7 @@ static unsigned long move_vma(struct vm_
}
/* Conceal VM_ACCOUNT so old reservation is not undone */
- if (vm_flags & VM_ACCOUNT) {
+ if (vm_flags & VM_ACCOUNT && !(flags & MREMAP_DONTUNMAP)) {
vma->vm_flags &= ~VM_ACCOUNT;
excess = vma->vm_end - vma->vm_start - old_len;
if (old_addr > vma->vm_start &&
@@ -573,34 +581,16 @@ static unsigned long move_vma(struct vm_
untrack_pfn_moved(vma);
if (unlikely(!err && (flags & MREMAP_DONTUNMAP))) {
- if (vm_flags & VM_ACCOUNT) {
- /* Always put back VM_ACCOUNT since we won't unmap */
- vma->vm_flags |= VM_ACCOUNT;
-
- vm_acct_memory(new_len >> PAGE_SHIFT);
- }
-
- /*
- * VMAs can actually be merged back together in copy_vma
- * calling merge_vma. This can happen with anonymous vmas
- * which have not yet been faulted, so if we were to consider
- * this VMA split we'll end up adding VM_ACCOUNT on the
- * next VMA, which is completely unrelated if this VMA
- * was re-merged.
- */
- if (split && new_vma == vma)
- split = 0;
-
/* We always clear VM_LOCKED[ONFAULT] on the old vma */
vma->vm_flags &= VM_LOCKED_CLEAR_MASK;
/* Because we won't unmap we don't need to touch locked_vm */
- goto out;
+ return new_addr;
}
if (do_munmap(mm, old_addr, old_len, uf_unmap) < 0) {
/* OOM: unable to split vma, just get accounts right */
- if (vm_flags & VM_ACCOUNT)
+ if (vm_flags & VM_ACCOUNT && !(flags & MREMAP_DONTUNMAP))
vm_acct_memory(new_len >> PAGE_SHIFT);
excess = 0;
}
@@ -609,7 +599,7 @@ static unsigned long move_vma(struct vm_
mm->locked_vm += new_len >> PAGE_SHIFT;
*locked = true;
}
-out:
+
mm->hiwater_vm = hiwater_vm;
/* Restore VM_ACCOUNT if one or two pieces of vma left */
_
Patches currently in -mm which might be from dima@xxxxxxxxxx are
