Re: [Qemu-block] [PATCH v7 27/39] block: Add blk_remove_bs()

[Max Reitz]

On 20.10.2015 10:33, Kevin Wolf wrote:
> Am 19.10.2015 um 17:53 hat Max Reitz geschrieben:
>> This function removes the BlockDriverState associated with the given
>> BlockBackend from that BB and sets the BDS pointer in the BB to NULL.
>>
>> Signed-off-by: Max Reitz 
>> ---
>>  block/block-backend.c  | 12 
>>  include/sysemu/block-backend.h |  1 +
>>  2 files changed, 13 insertions(+)
>>
>> diff --git a/block/block-backend.c b/block/block-backend.c
>> index 19fdaae..eb7409c 100644
>> --- a/block/block-backend.c
>> +++ b/block/block-backend.c
>> @@ -334,6 +334,18 @@ void blk_hide_on_behalf_of_hmp_drive_del(BlockBackend 
>> *blk)
>>  }
>>  
>>  /*
>> + * Disassociates the currently associated BlockDriverState from @blk.
>> + */
>> +void blk_remove_bs(BlockBackend *blk)
>> +{
>> +blk_update_root_state(blk);
>> +
>> +bdrv_unref(blk->bs);
>> +blk->bs->blk = NULL;
> 
> Use after free?

Yes, indeed, will fix.

Max

>> +blk->bs = NULL;
>> +}
> 
> Kevin
> 




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Re: [Qemu-block] [PATCH v7 27/39] block: Add blk_remove_bs()

[Kevin Wolf]

Am 19.10.2015 um 17:53 hat Max Reitz geschrieben:
> This function removes the BlockDriverState associated with the given
> BlockBackend from that BB and sets the BDS pointer in the BB to NULL.
> 
> Signed-off-by: Max Reitz 
> ---
>  block/block-backend.c  | 12 
>  include/sysemu/block-backend.h |  1 +
>  2 files changed, 13 insertions(+)
> 
> diff --git a/block/block-backend.c b/block/block-backend.c
> index 19fdaae..eb7409c 100644
> --- a/block/block-backend.c
> +++ b/block/block-backend.c
> @@ -334,6 +334,18 @@ void blk_hide_on_behalf_of_hmp_drive_del(BlockBackend 
> *blk)
>  }
>  
>  /*
> + * Disassociates the currently associated BlockDriverState from @blk.
> + */
> +void blk_remove_bs(BlockBackend *blk)
> +{
> +blk_update_root_state(blk);
> +
> +bdrv_unref(blk->bs);
> +blk->bs->blk = NULL;

Use after free?

> +blk->bs = NULL;
> +}

Kevin

[Qemu-block] [PATCH v7 27/39] block: Add blk_remove_bs()

[Max Reitz]

This function removes the BlockDriverState associated with the given
BlockBackend from that BB and sets the BDS pointer in the BB to NULL.

Signed-off-by: Max Reitz 
---
 block/block-backend.c  | 12 
 include/sysemu/block-backend.h |  1 +
 2 files changed, 13 insertions(+)

diff --git a/block/block-backend.c b/block/block-backend.c
index 19fdaae..eb7409c 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -334,6 +334,18 @@ void blk_hide_on_behalf_of_hmp_drive_del(BlockBackend *blk)
 }
 
 /*
+ * Disassociates the currently associated BlockDriverState from @blk.
+ */
+void blk_remove_bs(BlockBackend *blk)
+{
+blk_update_root_state(blk);
+
+bdrv_unref(blk->bs);
+blk->bs->blk = NULL;
+blk->bs = NULL;
+}
+
+/*
  * Associates a new BlockDriverState with @blk.
  */
 void blk_insert_bs(BlockBackend *blk, BlockDriverState *bs)
diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h
index 9306a52..14a6d32 100644
--- a/include/sysemu/block-backend.h
+++ b/include/sysemu/block-backend.h
@@ -72,6 +72,7 @@ BlockBackend *blk_by_name(const char *name);
 BlockBackend *blk_next(BlockBackend *blk);
 
 BlockDriverState *blk_bs(BlockBackend *blk);
+void blk_remove_bs(BlockBackend *blk);
 void blk_insert_bs(BlockBackend *blk, BlockDriverState *bs);
 
 void blk_hide_on_behalf_of_hmp_drive_del(BlockBackend *blk);
-- 
2.6.1