The Wednesday 28 May 2014 à 16:37:43 (+0200), Kevin Wolf wrote :
> Some code in the block layer makes potentially huge allocations. Failure
> is not completely unexpected there, so avoid aborting qemu and handle
> out-of-memory situations gracefully.
>
> This patch addresses the allocations in the qcow1 block driver.
>
> Signed-off-by: Kevin Wolf <kw...@redhat.com>
> Reviewed-by: Stefan Hajnoczi <stefa...@redhat.com>
> ---
> block/qcow.c | 33 ++++++++++++++++++++++++++-------
> 1 file changed, 26 insertions(+), 7 deletions(-)
>
> diff --git a/block/qcow.c b/block/qcow.c
> index 7fd57d7..31db585 100644
> --- a/block/qcow.c
> +++ b/block/qcow.c
> @@ -182,7 +182,12 @@ static int qcow_open(BlockDriverState *bs, QDict
> *options, int flags,
> }
>
> s->l1_table_offset = header.l1_table_offset;
> - s->l1_table = g_malloc(s->l1_size * sizeof(uint64_t));
> + s->l1_table = g_try_malloc(s->l1_size * sizeof(uint64_t));
> + if (s->l1_table == NULL) {
> + error_setg(errp, "Could not allocate memory for L1 table");
> + ret = -ENOMEM;
> + goto fail;
> + }
>
> ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table,
> s->l1_size * sizeof(uint64_t));
> @@ -193,8 +198,16 @@ static int qcow_open(BlockDriverState *bs, QDict
> *options, int flags,
> for(i = 0;i < s->l1_size; i++) {
> be64_to_cpus(&s->l1_table[i]);
> }
> - /* alloc L2 cache */
> - s->l2_cache = g_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
> +
> + /* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */
> + s->l2_cache =
> + qemu_try_blockalign(bs->file,
> + s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
> + if (s->l2_cache == NULL) {
> + error_setg(errp, "Could not allocate L2 table cache");
> + ret = -ENOMEM;
> + goto fail;
> + }
> s->cluster_cache = g_malloc(s->cluster_size);
> s->cluster_data = g_malloc(s->cluster_size);
> s->cluster_cache_offset = -1;
> @@ -226,7 +239,7 @@ static int qcow_open(BlockDriverState *bs, QDict
> *options, int flags,
>
> fail:
> g_free(s->l1_table);
> - g_free(s->l2_cache);
> + qemu_vfree(s->l2_cache);
> g_free(s->cluster_cache);
> g_free(s->cluster_data);
> return ret;
> @@ -517,7 +530,10 @@ static coroutine_fn int qcow_co_readv(BlockDriverState
> *bs, int64_t sector_num,
> void *orig_buf;
>
> if (qiov->niov > 1) {
> - buf = orig_buf = qemu_blockalign(bs, qiov->size);
> + buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
What if qiov->size == 0 ? (posix_memalign will return NULL)
> + if (buf == NULL) {
> + return -ENOMEM;
> + }
> } else {
> orig_buf = NULL;
> buf = (uint8_t *)qiov->iov->iov_base;
> @@ -619,7 +635,10 @@ static coroutine_fn int qcow_co_writev(BlockDriverState
> *bs, int64_t sector_num,
> s->cluster_cache_offset = -1; /* disable compressed cache */
>
> if (qiov->niov > 1) {
> - buf = orig_buf = qemu_blockalign(bs, qiov->size);
> + buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
Same ?
> + if (buf == NULL) {
> + return -ENOMEM;
> + }
> qemu_iovec_to_buf(qiov, 0, buf, qiov->size);
> } else {
> orig_buf = NULL;
> @@ -685,7 +704,7 @@ static void qcow_close(BlockDriverState *bs)
> BDRVQcowState *s = bs->opaque;
>
> g_free(s->l1_table);
> - g_free(s->l2_cache);
> + qemu_vfree(s->l2_cache);
> g_free(s->cluster_cache);
> g_free(s->cluster_data);
>
> --
> 1.8.3.1
>
>
