[Qemu-devel] [PATCH v4 04/21] cloop: Handle failure for potentially large allocations

[Kevin Wolf <kwolf@redhat.com>]

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 cloop block driver.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
---
 block/cloop.c | 23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/block/cloop.c b/block/cloop.c
index 8457737..f328be0 100644
--- a/block/cloop.c
+++ b/block/cloop.c
@@ -116,7 +116,12 @@ static int cloop_open(BlockDriverState *bs, QDict *options, int flags,
                    "try increasing block size");
         return -EINVAL;
     }
-    s->offsets = g_malloc(offsets_size);
+
+    s->offsets = g_try_malloc(offsets_size);
+    if (s->offsets == NULL) {
+        error_setg(errp, "Could not allocate offsets table");
+        return -ENOMEM;
+    }
 
     ret = bdrv_pread(bs->file, 128 + 4 + 4, s->offsets, offsets_size);
     if (ret < 0) {
@@ -158,8 +163,20 @@ static int cloop_open(BlockDriverState *bs, QDict *options, int flags,
     }
 
     /* initialize zlib engine */
-    s->compressed_block = g_malloc(max_compressed_block_size + 1);
-    s->uncompressed_block = g_malloc(s->block_size);
+    s->compressed_block = g_try_malloc(max_compressed_block_size + 1);
+    if (s->compressed_block == NULL) {
+        error_setg(errp, "Could not allocate compressed_block");
+        ret = -ENOMEM;
+        goto fail;
+    }
+
+    s->uncompressed_block = g_try_malloc(s->block_size);
+    if (s->uncompressed_block == NULL) {
+        error_setg(errp, "Could not allocate uncompressed_block");
+        ret = -ENOMEM;
+        goto fail;
+    }
+
     if (inflateInit(&s->zstream) != Z_OK) {
         ret = -EINVAL;
         goto fail;
-- 
1.8.3.1