From: Namjae Jeon Date: Fri, 10 Apr 2026 14:49:01 +0000 (+0900) Subject: ntfs: fix uninitialized pointer in ntfs_write_mft_block X-Git-Tag: v7.1-rc1~14^2~7 X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=545834ac412fb42d41a41442aee7998c1d2dcced;p=thirdparty%2Flinux.git ntfs: fix uninitialized pointer in ntfs_write_mft_block Smatch reported that the variable rl could be used uninitialized in ntfs_write_mft_block(). After analyzing the code, when vol->cluster_size == NTFS_BLOCK_SIZE (512), it is smaller than folio_size, so rl is guaranteed to be initialized. If vol->cluster_size is larger, the condition to access rl becomes false, so a runtime error is not expected to occur. However, to make the static checker happy, this patch initializes rl to NULL and adds an explicit check before its usage. Reported-by: Dan Carpenter Reviewed-by: Hyunchul Lee Signed-off-by: Namjae Jeon --- diff --git a/fs/ntfs/mft.c b/fs/ntfs/mft.c index bf028c1aea26..60d64de51d21 100644 --- a/fs/ntfs/mft.c +++ b/fs/ntfs/mft.c @@ -2714,7 +2714,7 @@ static int ntfs_write_mft_block(struct folio *folio, struct writeback_control *w s64 vcn = ntfs_pidx_to_cluster(vol, folio->index); s64 end_vcn = ntfs_bytes_to_cluster(vol, ni->allocated_size); unsigned int folio_sz; - struct runlist_element *rl; + struct runlist_element *rl = NULL; loff_t i_size = i_size_read(vi); ntfs_debug("Entering for inode 0x%llx, attribute type 0x%x, folio index 0x%lx.", @@ -2820,7 +2820,7 @@ flush_bio: if (vol->cluster_size == NTFS_BLOCK_SIZE && (mft_record_off || - rl->length - (vcn_off - rl->vcn) == 1 || + (rl && rl->length - (vcn_off - rl->vcn) == 1) || mft_ofs + NTFS_BLOCK_SIZE >= PAGE_SIZE)) folio_sz = NTFS_BLOCK_SIZE; else