[PATCH v2 3/5] mremap: don't do mm_populate(new_addr) on failure

From: Oleg Nesterov
Date: Wed Jul 01 2015 - 19:05:12 EST


move_vma() sets *locked even if move_page_tables() or ->mremap()
fails, change sys_mremap() to check "ret & ~PAGE_MASK".

I think we should simply remove the VM_LOCKED code in move_vma(),
that is why this patch doesn't change move_vma(). But this needs
more cleanups.

Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
---
mm/mremap.c | 4 +++-
1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/mm/mremap.c b/mm/mremap.c
index 3310378..7dcf7b4 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -578,8 +578,10 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
ret = move_vma(vma, addr, old_len, new_len, new_addr, &locked);
}
out:
- if (ret & ~PAGE_MASK)
+ if (ret & ~PAGE_MASK) {
vm_unacct_memory(charged);
+ locked = 0;
+ }
up_write(&current->mm->mmap_sem);
if (locked && new_len > old_len)
mm_populate(new_addr + old_len, new_len - old_len);
--
1.5.5.1

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