diff options
| author | Ming Lei <ming.lei@redhat.com> | 2026-01-16 22:18:48 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2026-01-22 20:05:41 -0700 |
| commit | caf84294ff98bb7455722285f30f46c193ffccdd (patch) | |
| tree | e98f08ae4abc4aee079780c3bab1ae7501dd5b90 /tools | |
| parent | 3f3850785594e323c5adc6b19ef5907419d3159f (diff) | |
selftests: ublk: fix user_data truncation for tgt_data >= 256
The build_user_data() function packs multiple fields into a __u64
value using bit shifts. Without explicit __u64 casts before shifting,
the shift operations are performed on 32-bit unsigned integers before
being promoted to 64-bit, causing data loss.
Specifically, when tgt_data >= 256, the expression (tgt_data << 24)
shifts on a 32-bit value, truncating the upper 8 bits before promotion
to __u64. Since tgt_data can be up to 16 bits (assertion allows up to
65535), values >= 256 would have their high byte lost.
Add explicit __u64 casts to both op and tgt_data before shifting to
ensure the shift operations happen in 64-bit space, preserving all
bits of the input values.
user_data_to_tgt_data() is only used by stripe.c, in which the max
supported member disks are 4, so won't trigger this issue.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/testing/selftests/ublk/kublk.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/tools/testing/selftests/ublk/kublk.h b/tools/testing/selftests/ublk/kublk.h index cb757fd9bf9d..69fd5794f300 100644 --- a/tools/testing/selftests/ublk/kublk.h +++ b/tools/testing/selftests/ublk/kublk.h @@ -262,7 +262,7 @@ static inline __u64 build_user_data(unsigned tag, unsigned op, _Static_assert(UBLK_MAX_QUEUES_SHIFT <= 7); assert(!(tag >> 16) && !(op >> 8) && !(tgt_data >> 16) && !(q_id >> 7)); - return tag | (op << 16) | (tgt_data << 24) | + return tag | ((__u64)op << 16) | ((__u64)tgt_data << 24) | (__u64)q_id << 56 | (__u64)is_target_io << 63; } |