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ntfs: fix uninitialized pointer in ntfs_write_mft_block

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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 <error27@gmail.com>
Reviewed-by: Hyunchul Lee <hyc.lee@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
This commit is contained in:
Namjae Jeon 2026-04-10 23:49:01 +09:00
parent 8a59a2d84f
commit 545834ac41
1 changed files with 2 additions and 2 deletions
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4
fs/ntfs/mft.c
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@ -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 @@ static int ntfs_write_mft_block(struct folio *folio, struct writeback_control *w
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