[Qemu-devel] [PATCH] block: Fix 32 bit truncation in mark_request_serialising()

[Qemu-devel] [PATCH] block: Fix 32 bit truncation in mark_request_serialising()

[Kevin Wolf]

On 32 bit hosts, size_t is too small for align as the bitmask
~(align - 1) will zero out the higher 32 bits of the offset.

While at it, change the local overlap_bytes variable to unsigned to
match the field in BdrvTrackedRequest.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/block.c b/block.c
index b0c5025..636aa11 100644
--- a/block.c
+++ b/block.c
@@ -2240,11 +2240,11 @@ static void tracked_request_begin(BdrvTrackedRequest *req,
     QLIST_INSERT_HEAD(&bs->tracked_requests, req, list);
 }
 
-static void mark_request_serialising(BdrvTrackedRequest *req, size_t align)
+static void mark_request_serialising(BdrvTrackedRequest *req, uint64_t align)
 {
     int64_t overlap_offset = req->offset & ~(align - 1);
-    int overlap_bytes = ROUND_UP(req->offset + req->bytes, align)
-                      - overlap_offset;
+    unsigned int overlap_bytes = ROUND_UP(req->offset + req->bytes, align)
+                               - overlap_offset;
 
     if (!req->serialising) {
         req->bs->serialising_in_flight++;
-- 
1.8.1.4

Re: [Qemu-devel] [PATCH] block: Fix 32 bit truncation in mark_request_serialising()

[Laszlo Ersek]

On 02/08/14 10:47, Kevin Wolf wrote:
> On 32 bit hosts, size_t is too small for align as the bitmask
> ~(align - 1) will zero out the higher 32 bits of the offset.
> 
> While at it, change the local overlap_bytes variable to unsigned to
> match the field in BdrvTrackedRequest.
> 
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>  block.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/block.c b/block.c
> index b0c5025..636aa11 100644
> --- a/block.c
> +++ b/block.c
> @@ -2240,11 +2240,11 @@ static void tracked_request_begin(BdrvTrackedRequest *req,
>      QLIST_INSERT_HEAD(&bs->tracked_requests, req, list);
>  }
>  
> -static void mark_request_serialising(BdrvTrackedRequest *req, size_t align)
> +static void mark_request_serialising(BdrvTrackedRequest *req, uint64_t align)
>  {
>      int64_t overlap_offset = req->offset & ~(align - 1);
> -    int overlap_bytes = ROUND_UP(req->offset + req->bytes, align)
> -                      - overlap_offset;
> +    unsigned int overlap_bytes = ROUND_UP(req->offset + req->bytes, align)
> +                               - overlap_offset;
>  
>      if (!req->serialising) {
>          req->bs->serialising_in_flight++;
> 

Reviewed-by: Laszlo Ersek <lersek@redhat.com>

Thanks!
Laszlo