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Re: [PATCH V2] block/nbd: fix memory leak in nbd_open()
From: |
Stefano Garzarella |
Subject: |
Re: [PATCH V2] block/nbd: fix memory leak in nbd_open() |
Date: |
Thu, 28 Nov 2019 14:36:37 +0100 |
On Thu, Nov 28, 2019 at 08:09:31PM +0800, address@hidden wrote:
> From: PanNengyuan <address@hidden>
>
> In currently implementation there will be a memory leak when
> nbd_client_connect() returns error status. Here is an easy way to
> reproduce:
>
> 1. run qemu-iotests as follow and check the result with asan:
> ./check -raw 143
>
> Following is the asan output backtrack:
> Direct leak of 40 byte(s) in 1 object(s) allocated from:
> #0 0x7f629688a560 in calloc (/usr/lib64/libasan.so.3+0xc7560)
> #1 0x7f6295e7e015 in g_malloc0 (/usr/lib64/libglib-2.0.so.0+0x50015)
> #2 0x56281dab4642 in qobject_input_start_struct
> /mnt/sdb/qemu-4.2.0-rc0/qapi/qobject-input-visitor.c:295
> #3 0x56281dab1a04 in visit_start_struct
> /mnt/sdb/qemu-4.2.0-rc0/qapi/qapi-visit-core.c:49
> #4 0x56281dad1827 in visit_type_SocketAddress
> qapi/qapi-visit-sockets.c:386
> #5 0x56281da8062f in nbd_config /mnt/sdb/qemu-4.2.0-rc0/block/nbd.c:1716
> #6 0x56281da8062f in nbd_process_options
> /mnt/sdb/qemu-4.2.0-rc0/block/nbd.c:1829
> #7 0x56281da8062f in nbd_open /mnt/sdb/qemu-4.2.0-rc0/block/nbd.c:1873
>
> Direct leak of 15 byte(s) in 1 object(s) allocated from:
> #0 0x7f629688a3a0 in malloc (/usr/lib64/libasan.so.3+0xc73a0)
> #1 0x7f6295e7dfbd in g_malloc (/usr/lib64/libglib-2.0.so.0+0x4ffbd)
> #2 0x7f6295e96ace in g_strdup (/usr/lib64/libglib-2.0.so.0+0x68ace)
> #3 0x56281da804ac in nbd_process_options
> /mnt/sdb/qemu-4.2.0-rc0/block/nbd.c:1834
> #4 0x56281da804ac in nbd_open /mnt/sdb/qemu-4.2.0-rc0/block/nbd.c:1873
>
> Indirect leak of 24 byte(s) in 1 object(s) allocated from:
> #0 0x7f629688a3a0 in malloc (/usr/lib64/libasan.so.3+0xc73a0)
> #1 0x7f6295e7dfbd in g_malloc (/usr/lib64/libglib-2.0.so.0+0x4ffbd)
> #2 0x7f6295e96ace in g_strdup (/usr/lib64/libglib-2.0.so.0+0x68ace)
> #3 0x56281dab41a3 in qobject_input_type_str_keyval
> /mnt/sdb/qemu-4.2.0-rc0/qapi/qobject-input-visitor.c:536
> #4 0x56281dab2ee9 in visit_type_str
> /mnt/sdb/qemu-4.2.0-rc0/qapi/qapi-visit-core.c:297
> #5 0x56281dad0fa1 in visit_type_UnixSocketAddress_members
> qapi/qapi-visit-sockets.c:141
> #6 0x56281dad17b6 in visit_type_SocketAddress_members
> qapi/qapi-visit-sockets.c:366
> #7 0x56281dad186a in visit_type_SocketAddress
> qapi/qapi-visit-sockets.c:393
> #8 0x56281da8062f in nbd_config /mnt/sdb/qemu-4.2.0-rc0/block/nbd.c:1716
> #9 0x56281da8062f in nbd_process_options
> /mnt/sdb/qemu-4.2.0-rc0/block/nbd.c:1829
> #10 0x56281da8062f in nbd_open /mnt/sdb/qemu-4.2.0-rc0/block/nbd.c:1873
>
> Reported-by: Euler Robot <address@hidden>
> Signed-off-by: PanNengyuan <address@hidden>
> ---
> Changes v2 to v1:
> - add a new function to do the common cleanups (suggested by Stefano
> Garzarella).
> ---
> block/nbd.c | 26 ++++++++++++++++----------
> 1 file changed, 16 insertions(+), 10 deletions(-)
>
> diff --git a/block/nbd.c b/block/nbd.c
> index 1239761..f8aa2a8 100644
> --- a/block/nbd.c
> +++ b/block/nbd.c
> @@ -94,6 +94,8 @@ typedef struct BDRVNBDState {
>
> static int nbd_client_connect(BlockDriverState *bs, Error **errp);
>
> +static void nbd_free_bdrvstate_prop(BDRVNBDState *s);
> +
> static void nbd_channel_error(BDRVNBDState *s, int ret)
> {
> if (ret == -EIO) {
> @@ -1486,6 +1488,17 @@ static int nbd_client_connect(BlockDriverState *bs,
> Error **errp)
> }
> }
>
> +static void nbd_free_bdrvstate_prop(BDRVNBDState *s)
> +{
> + object_unref(OBJECT(s->tlscreds));
> + qapi_free_SocketAddress(s->saddr);
> + g_free(s->export);
> + g_free(s->tlscredsid);
> + if (s->x_dirty_bitmap) {
^ it is not needed, g_free() handles NULL pointers.
> + g_free(s->x_dirty_bitmap);
> + }
> +}
> +
Please, split this patch in two patches:
- the first patch where you add this function and use it in
nbd_process_options() and nbd_close()
- the second patch where you fix the leak in nbd_open()
Thanks,
Stefano
> /*
> * Parse nbd_open options
> */
> @@ -1855,10 +1868,7 @@ static int nbd_process_options(BlockDriverState *bs,
> QDict *options,
>
> error:
> if (ret < 0) {
> - object_unref(OBJECT(s->tlscreds));
> - qapi_free_SocketAddress(s->saddr);
> - g_free(s->export);
> - g_free(s->tlscredsid);
> + nbd_free_bdrvstate_prop(s);
> }
> qemu_opts_del(opts);
> return ret;
> @@ -1881,6 +1891,7 @@ static int nbd_open(BlockDriverState *bs, QDict
> *options, int flags,
>
> ret = nbd_client_connect(bs, errp);
> if (ret < 0) {
> + nbd_free_bdrvstate_prop(s);
> return ret;
> }
> /* successfully connected */
> @@ -1937,12 +1948,7 @@ static void nbd_close(BlockDriverState *bs)
> BDRVNBDState *s = bs->opaque;
>
> nbd_client_close(bs);
> -
> - object_unref(OBJECT(s->tlscreds));
> - qapi_free_SocketAddress(s->saddr);
> - g_free(s->export);
> - g_free(s->tlscredsid);
> - g_free(s->x_dirty_bitmap);
> + nbd_free_bdrvstate_prop(s);
> }
>
> static int64_t nbd_getlength(BlockDriverState *bs)
> --
> 2.7.2.windows.1
>
>
>
--