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[PULL,44/62] dmg: Handle failure for potentially large allocations

Message ID 1407519603-6635-45-git-send-email-kwolf@redhat.com
State New
Headers show

Commit Message

Kevin Wolf Aug. 8, 2014, 5:39 p.m. UTC 
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 dmg 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/dmg.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)
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Patch

diff --git a/block/dmg.c b/block/dmg.c
index 1e153cd..e455886 100644
--- a/block/dmg.c
+++ b/block/dmg.c
@@ -284,8 +284,15 @@  static int dmg_open(BlockDriverState *bs, QDict *options, int flags,
     }
 
     /* initialize zlib engine */
-    s->compressed_chunk = g_malloc(max_compressed_size + 1);
-    s->uncompressed_chunk = g_malloc(512 * max_sectors_per_chunk);
+    s->compressed_chunk = qemu_try_blockalign(bs->file,
+                                              max_compressed_size + 1);
+    s->uncompressed_chunk = qemu_try_blockalign(bs->file,
+                                                512 * max_sectors_per_chunk);
+    if (s->compressed_chunk == NULL || s->uncompressed_chunk == NULL) {
+        ret = -ENOMEM;
+        goto fail;
+    }
+
     if (inflateInit(&s->zstream) != Z_OK) {
         ret = -EINVAL;
         goto fail;
@@ -302,8 +309,8 @@  fail:
     g_free(s->lengths);
     g_free(s->sectors);
     g_free(s->sectorcounts);
-    g_free(s->compressed_chunk);
-    g_free(s->uncompressed_chunk);
+    qemu_vfree(s->compressed_chunk);
+    qemu_vfree(s->uncompressed_chunk);
     return ret;
 }
 
@@ -426,8 +433,8 @@  static void dmg_close(BlockDriverState *bs)
     g_free(s->lengths);
     g_free(s->sectors);
     g_free(s->sectorcounts);
-    g_free(s->compressed_chunk);
-    g_free(s->uncompressed_chunk);
+    qemu_vfree(s->compressed_chunk);
+    qemu_vfree(s->uncompressed_chunk);
 
     inflateEnd(&s->zstream);
 }