[PATCH] tools: usb: ffs-test: read the descriptor counts with unaligned accesses
From: Sasha Levin
Date: Sun Oct 11 2026 - 18:38:58 EST
descs_to_legacy() reads the descriptor counts through a __le32 pointer
taken from a member of a packed struct, which may be unaligned:
ffs-test.c:235:40: warning: taking address of packed member of 'struct <anonymous>' may result in an unaligned pointer value [-Waddress-of-packed-member]
Walk the counts with a byte pointer and get_unaligned_le32().
Fixes: b9a4274699c69 ("tools: ffs-test: add compatibility code for old kernels")
Assisted-by: LLM
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
tools/usb/ffs-test.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/tools/usb/ffs-test.c b/tools/usb/ffs-test.c
index 22b938fbdfb77..f08060459b3f1 100644
--- a/tools/usb/ffs-test.c
+++ b/tools/usb/ffs-test.c
@@ -232,7 +232,8 @@ static size_t descs_to_legacy(void **legacy, const void *descriptors_v2)
const struct usb_functionfs_descs_head_v2 header;
const __le32 counts[];
} __attribute__((packed)) *const in = descriptors_v2;
- const __le32 *counts = in->counts;
+ const unsigned char *counts =
+ (const unsigned char *)descriptors_v2 + sizeof(in->header);
__u32 flags;
if (le32_to_cpu(in->header.magic) !=
@@ -252,9 +253,9 @@ static size_t descs_to_legacy(void **legacy, const void *descriptors_v2)
break; \
if (length < 4) \
return 0; \
- ret = le32_to_cpu(*counts); \
+ ret = get_unaligned_le32(counts); \
length -= 4; \
- ++counts; \
+ counts += 4; \
} while (0)
GET_NEXT_COUNT_IF_FLAG(fs_count, FUNCTIONFS_HAS_FS_DESC);
--
2.53.0