From: Xiubo Li <lixiubo@xxxxxxxxxxxxxxxxxxxx>
For most case the sg->length equals to PAGE_SIZE, so this bug won't
be triggered. Otherwise this will crash the kernel, for example when
all segments' sg->length equal to 1K.
Signed-off-by: Xiubo Li <lixiubo@xxxxxxxxxxxxxxxxxxxx>
---
drivers/target/target_core_user.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c
index 8bf0823..9030c2a 100644
--- a/drivers/target/target_core_user.c
+++ b/drivers/target/target_core_user.c
@@ -590,8 +590,6 @@ static int scatter_data_area(struct tcmu_dev *udev,
block_remaining);
to_offset = get_block_offset_user(udev, dbi,
block_remaining);
- offset = DATA_BLOCK_SIZE - block_remaining;
- to += offset;
if (*iov_cnt != 0 &&
to_offset == iov_tail(*iov)) {
@@ -602,8 +600,10 @@ static int scatter_data_area(struct tcmu_dev *udev,
(*iov)->iov_len = copy_bytes;
}
if (copy_data) {
- memcpy(to, from + sg->length - sg_remaining,
- copy_bytes);
+ offset = DATA_BLOCK_SIZE - block_remaining;
+ memcpy(to + offset,
+ from + sg->length - sg_remaining,
+ copy_bytes);
tcmu_flush_dcache_range(to, copy_bytes);
}
sg_remaining -= copy_bytes;
@@ -664,9 +664,8 @@ static void gather_data_area(struct tcmu_dev *udev, struct tcmu_cmd *cmd,
copy_bytes = min_t(size_t, sg_remaining,
block_remaining);
offset = DATA_BLOCK_SIZE - block_remaining;
- from += offset;
tcmu_flush_dcache_range(from, copy_bytes);
- memcpy(to + sg->length - sg_remaining, from,
+ memcpy(to + sg->length - sg_remaining, from + offset,
copy_bytes);
sg_remaining -= copy_bytes;
--
1.8.3.1
--
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