[PATCH v3] mm: shmem: Use signed int for version handling in casefold option

[PATCH v3] mm: shmem: Use signed int for version handling in casefold option

[Karan Sanghavi]

Fixes an issue where the use of an unsigned data type in
`shmem_parse_opt_casefold()` caused incorrect evaluation of
negative conditions.

Fixes: 58e55efd6c72 ("tmpfs: Add casefold lookup support")
Reviewed-by: André Almeida <andrealmeid@igalia.com>
Reviewed-by: Gabriel Krisman Bertazi <gabriel@krisman.be>
Signed-off-by: Karan Sanghavi <karansanghvi98@gmail.com>
---
Coverity Message:
CID 1601569: (#1 of 1): Unsigned compared against 0 (NO_EFFECT)
unsigned_compare: This less-than-zero comparison of an unsigned 
value is never true. version < 0U

Coverity Link:
https://scan7.scan.coverity.com/#/project-view/10043/11354?selectedIssue=1601569
---
Changes in v3:
- Changed patch subject adn summary log. 
- Link to v2: https://lore.kernel.org/r/20241127-unsignedcompare1601569-v2-1-e85098fb02b2@gmail.com

Changes in v2:
- Updated the log summary.
- Link to v1: https://lore.kernel.org/r/20241111-unsignedcompare1601569-v1-1-c4a9c3c75a52@gmail.com
---
 mm/shmem.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/shmem.c b/mm/shmem.c
index 7987deb2be9b..17a1d4fa8870 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -4367,7 +4367,7 @@ static int shmem_parse_opt_casefold(struct fs_context *fc, struct fs_parameter *
 				    bool latest_version)
 {
 	struct shmem_options *ctx = fc->fs_private;
-	unsigned int version = UTF8_LATEST;
+	int version = UTF8_LATEST;
 	struct unicode_map *encoding;
 	char *version_str = param->string + 5;
 

---
base-commit: 6d59cab07b8d74d0f0422b750038123334f6ecc2
change-id: 20241111-unsignedcompare1601569-05b5932145ef

Best regards,
-- 
Karan Sanghavi <karansanghvi98@gmail.com>

Re: [PATCH v3] mm: shmem: Use signed int for version handling in casefold option

[Christian Brauner]

On Sat, 11 Jan 2025 15:31:30 +0000, Karan Sanghavi wrote:
> Fixes an issue where the use of an unsigned data type in
> `shmem_parse_opt_casefold()` caused incorrect evaluation of
> negative conditions.
> 
> 

Applied to the vfs-6.14.misc branch of the vfs/vfs.git tree.
Patches in the vfs-6.14.misc branch should appear in linux-next soon.

Please report any outstanding bugs that were missed during review in a
new review to the original patch series allowing us to drop it.

It's encouraged to provide Acked-bys and Reviewed-bys even though the
patch has now been applied. If possible patch trailers will be updated.

Note that commit hashes shown below are subject to change due to rebase,
trailer updates or similar. If in doubt, please check the listed branch.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
branch: vfs-6.14.misc

[1/1] mm: shmem: Use signed int for version handling in casefold option
      https://git.kernel.org/vfs/vfs/c/5fb18263e9bf