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| author | Miaohe Lin <linmiaohe@huawei.com> | 2022-06-09 21:08:35 +0800 |
|---|---|---|
| committer | akpm <akpm@linux-foundation.org> | 2022-06-16 19:48:30 -0700 |
| commit | ed913b055a74b723976f8e885a3395162a0371e6 (patch) | |
| tree | f072fe1621a6904e3e78a851f9fce5134d365f49 /lib/test_hmm.c | |
| parent | 23689037e0986724e3bdc41bb2ee6fa1b497b8f9 (diff) | |
| download | linux-ed913b055a74b723976f8e885a3395162a0371e6.tar.gz | |
lib/test_hmm: avoid accessing uninitialized pages
If make_device_exclusive_range() fails or returns pages marked for
exclusive access less than required, remaining fields of pages will left
uninitialized. So dmirror_atomic_map() will access those yet
uninitialized fields of pages. To fix it, do dmirror_atomic_map() iff all
pages are marked for exclusive access (we will break if mapped is less
than required anyway) so we won't access those uninitialized fields of
pages.
Link: https://lkml.kernel.org/r/20220609130835.35110-1-linmiaohe@huawei.com
Fixes: b659baea7546 ("mm: selftests for exclusive device memory")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'lib/test_hmm.c')
| -rw-r--r-- | lib/test_hmm.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/lib/test_hmm.c b/lib/test_hmm.c index cfe632047839..f2c3015c5c82 100644 --- a/lib/test_hmm.c +++ b/lib/test_hmm.c @@ -732,7 +732,7 @@ static int dmirror_exclusive(struct dmirror *dmirror, mmap_read_lock(mm); for (addr = start; addr < end; addr = next) { - unsigned long mapped; + unsigned long mapped = 0; int i; if (end < addr + (ARRAY_SIZE(pages) << PAGE_SHIFT)) @@ -741,7 +741,13 @@ static int dmirror_exclusive(struct dmirror *dmirror, next = addr + (ARRAY_SIZE(pages) << PAGE_SHIFT); ret = make_device_exclusive_range(mm, addr, next, pages, NULL); - mapped = dmirror_atomic_map(addr, next, pages, dmirror); + /* + * Do dmirror_atomic_map() iff all pages are marked for + * exclusive access to avoid accessing uninitialized + * fields of pages. + */ + if (ret == (next - addr) >> PAGE_SHIFT) + mapped = dmirror_atomic_map(addr, next, pages, dmirror); for (i = 0; i < ret; i++) { if (pages[i]) { unlock_page(pages[i]); |