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| author | Chen Wandun <chenwandun@huawei.com> | 2021-09-02 23:56:52 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-09-03 18:58:14 +0200 |
| commit | 5e22928abe671ea1541f19afb80523442938d342 (patch) | |
| tree | df069aa66121681aff125627899b8dea51457020 | |
| parent | remap_file_pages: Use vma_lookup() instead of find_vma() (diff) | |
| download | linux-5e22928abe671ea1541f19afb80523442938d342.tar.xz linux-5e22928abe671ea1541f19afb80523442938d342.zip | |
mm/mremap: fix memory account on do_munmap() failure
mremap will account the delta between new_len and old_len in
vma_to_resize, and then call move_vma when expanding an existing memory
mapping. In function move_vma, there are two scenarios when calling
do_munmap:
1. move_page_tables from old_addr to new_addr success
2. move_page_tables from old_addr to new_addr fail
In first scenario, it should account old_len if do_munmap fail, because
the delta has already been accounted.
In second scenario, new_addr/new_len will assign to old_addr/old_len if
move_page_table fail, so do_munmap is try to unmap new_addr actually, if
do_munmap fail, it should account the new_len, because error code will be
return from move_vma, and delta will be unaccounted. What'more, because
of new_len == old_len, so account old_len also is OK.
In summary, account old_len will be correct if do_munmap fail.
Link: https://lkml.kernel.org/r/20210717101942.120607-1-chenwandun@huawei.com
Fixes: 51df7bcb6151 ("mm/mremap: account memory on do_munmap() failure")
Signed-off-by: Chen Wandun <chenwandun@huawei.com>
Acked-by: Dmitry Safonov <dima@arista.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/mremap.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/mremap.c b/mm/mremap.c index 5989d3990020..badfe17ade1f 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -686,7 +686,7 @@ static unsigned long move_vma(struct vm_area_struct *vma, 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 && !(flags & MREMAP_DONTUNMAP)) - vm_acct_memory(new_len >> PAGE_SHIFT); + vm_acct_memory(old_len >> PAGE_SHIFT); excess = 0; } |