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Re: [Qemu-trivial] [PATCH v6 03/10] virtio-blk: fix reference a pointer
From: |
Michael Tokarev |
Subject: |
Re: [Qemu-trivial] [PATCH v6 03/10] virtio-blk: fix reference a pointer which might be freed |
Date: |
Thu, 14 Aug 2014 14:39:22 +0400 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Icedove/24.7.0 |
14.08.2014 14:37, Michael S. Tsirkin wrote:
> On Thu, Aug 14, 2014 at 03:29:14PM +0800, zhanghailiang wrote:
>> In function virtio_blk_handle_request, it may freed memory pointed by req,
>> So do not access member of req after calling this function.
>>
>> Reviewed-by: Stefan Hajnoczi <address@hidden>
>> Signed-off-by: zhanghailiang <address@hidden>
>
> Reviewed-by: Michael S. Tsirkin <address@hidden>
Just a small nitpick...
> Stefan want to pick up this one?
>
>> ---
>> hw/block/virtio-blk.c | 5 +++--
>> 1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
>> index c241c50..54a853a 100644
>> --- a/hw/block/virtio-blk.c
>> +++ b/hw/block/virtio-blk.c
>> @@ -458,7 +458,7 @@ static void virtio_blk_handle_output(VirtIODevice *vdev,
>> VirtQueue *vq)
>> static void virtio_blk_dma_restart_bh(void *opaque)
>> {
>> VirtIOBlock *s = opaque;
>> - VirtIOBlockReq *req = s->rq;
>> + VirtIOBlockReq *req = s->rq, *next = NULL;
There's no need to initialize next here.
With init like this I for one instinctively start searching below
how this `NULL' is used (which it isn't).
I'd declare it inside the loop too, since it is a local-to-loop
var, but that doesn't matter much.
/mjt
>> MultiReqBuffer mrb = {
>> .num_writes = 0,
>> };
>> @@ -469,8 +469,9 @@ static void virtio_blk_dma_restart_bh(void *opaque)
>> s->rq = NULL;
>>
>> while (req) {
>> + next = req->next;
>> virtio_blk_handle_request(req, &mrb);
>> - req = req->next;
>> + req = next;
>> }
>>
>> virtio_submit_multiwrite(s->bs, &mrb);
>> --
>> 1.7.12.4
>>
- Re: [Qemu-trivial] [Qemu-devel] [PATCH v6 07/10] linux-user: check return value of malloc(), (continued)
[Qemu-trivial] [PATCH v6 03/10] virtio-blk: fix reference a pointer which might be freed, zhanghailiang, 2014/08/14
Re: [Qemu-trivial] [PATCH v6 03/10] virtio-blk: fix reference a pointer which might be freed, Michael Tokarev, 2014/08/18
[Qemu-trivial] [PATCH v6 08/10] tests/bios-tables-test: check the value returned by fopen(), zhanghailiang, 2014/08/14
[Qemu-trivial] [PATCH v6 02/10] monitor: fix access freed memory, zhanghailiang, 2014/08/14