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drivers/md/md-bitmap: check the return value of md_bitmap_get_counter()

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Check the return value of md_bitmap_get_counter() in case it returns
NULL pointer, which will result in a null pointer dereference.

v2: update the check to include other dereference

Signed-off-by: Li Zhong <floridsleeves@gmail.com>
Signed-off-by: Song Liu <song@kernel.org>
This commit is contained in:
Li Zhong 2022-09-16 16:33:05 -07:00 committed by Song Liu
parent 4f8126bb23
commit 3bd548e5b8
1 changed files with 15 additions and 12 deletions
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27
drivers/md/md-bitmap.c
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@ -2195,20 +2195,23 @@ int md_bitmap_resize(struct bitmap *bitmap, sector_t blocks,
if (set) {
bmc_new = md_bitmap_get_counter(&bitmap->counts, block, &new_blocks, 1);
if (*bmc_new == 0) {
/* need to set on-disk bits too. */
sector_t end = block + new_blocks;
sector_t start = block >> chunkshift;
start <<= chunkshift;
while (start < end) {
md_bitmap_file_set_bit(bitmap, block);
start += 1 << chunkshift;
if (bmc_new) {
if (*bmc_new == 0) {
/* need to set on-disk bits too. */
sector_t end = block + new_blocks;
sector_t start = block >> chunkshift;
start <<= chunkshift;
while (start < end) {
md_bitmap_file_set_bit(bitmap, block);
start += 1 << chunkshift;
}
*bmc_new = 2;
md_bitmap_count_page(&bitmap->counts, block, 1);
md_bitmap_set_pending(&bitmap->counts, block);
}
*bmc_new = 2;
md_bitmap_count_page(&bitmap->counts, block, 1);
md_bitmap_set_pending(&bitmap->counts, block);
*bmc_new |= NEEDED_MASK;
}
*bmc_new |= NEEDED_MASK;
if (new_blocks < old_blocks)
old_blocks = new_blocks;
}