[Qemu-devel] [PATCH v4 07/21] iscsi: 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 iscsi block driver.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 block/iscsi.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/block/iscsi.c b/block/iscsi.c
index 3892cc5..b3e9bdd 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -335,7 +335,10 @@ static int coroutine_fn iscsi_co_writev(BlockDriverState *bs,
         data = iov->iov[0].iov_base;
     } else {
         size_t size = MIN(nb_sectors * BDRV_SECTOR_SIZE, iov->size);
-        buf = g_malloc(size);
+        buf = g_try_malloc(size);
+        if (size && buf == NULL) {
+            return -ENOMEM;
+        }
         qemu_iovec_to_buf(iov, 0, buf, size);
         data = buf;
     }
@@ -721,7 +724,12 @@ static BlockDriverAIOCB *iscsi_aio_ioctl(BlockDriverState *bs,
 #else
             struct iovec *iov = (struct iovec *)acb->ioh->dxferp;
 
-            acb->buf = g_malloc(acb->ioh->dxfer_len);
+            acb->buf = g_try_malloc(acb->ioh->dxfer_len);
+            if (acb->ioh->dxfer_len && acb->buf == NULL) {
+                free(acb->task);
+                qemu_aio_release(acb);
+                return NULL;
+            }
             data.data = acb->buf;
             data.size = iov_to_buf(iov, acb->ioh->iovec_count, 0,
                                    acb->buf, acb->ioh->dxfer_len);
@@ -902,7 +910,10 @@ coroutine_fn iscsi_co_write_zeroes(BlockDriverState *bs, int64_t sector_num,
     nb_blocks = sector_qemu2lun(nb_sectors, iscsilun);
 
     if (iscsilun->zeroblock == NULL) {
-        iscsilun->zeroblock = g_malloc0(iscsilun->block_size);
+        iscsilun->zeroblock = g_try_malloc0(iscsilun->block_size);
+        if (iscsilun->zeroblock == NULL) {
+            return -ENOMEM;
+        }
     }
 
     iscsi_co_init_iscsitask(iscsilun, &iTask);
-- 
1.8.3.1