Messages in this thread Patch in this message |  | | From | Sasha Levin <> | Subject | [PATCH AUTOSEL 5.4 17/30] drivers/md/md-bitmap: check the return value of md_bitmap_get_counter() | Date | Sun, 18 Dec 2022 11:18:22 -0500 |
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From: Li Zhong <floridsleeves@gmail.com>
[ Upstream commit 3bd548e5b819b8c0f2c9085de775c5c7bff9052f ]
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> Signed-off-by: Sasha Levin <sashal@kernel.org> --- drivers/md/md-bitmap.c | 27 +++++++++++++++------------ 1 file changed, 15 insertions(+), 12 deletions(-)
diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c index a95e20c3d0d4..72c30c99b29d 100644 --- a/drivers/md/md-bitmap.c +++ b/drivers/md/md-bitmap.c @@ -2200,20 +2200,23 @@ 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; } -- 2.35.1
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