[PATCH] block: Fix leak in send_qmp_error_event

[Fabiano Rosas]

ASAN detected a leak when running the ahci-test
/ahci/io/dma/lba28/retry:

Direct leak of 35 byte(s) in 1 object(s) allocated from:
    #0 in malloc
    #1 in __vasprintf_internal
    #2 in vasprintf
    #3 in g_vasprintf
    #4 in g_strdup_vprintf
    #5 in g_strdup_printf
    #6 in object_get_canonical_path ../qom/object.c:2096:19
    #7 in blk_get_attached_dev_id_or_path ../block/block-backend.c:1033:12
    #8 in blk_get_attached_dev_path ../block/block-backend.c:1047:12
    #9 in send_qmp_error_event ../block/block-backend.c:2140:36
    #10 in blk_error_action ../block/block-backend.c:2172:9
    #11 in ide_handle_rw_error ../hw/ide/core.c:875:5
    #12 in ide_dma_cb ../hw/ide/core.c:894:13
    #13 in dma_complete ../system/dma-helpers.c:107:9
    #14 in dma_blk_cb ../system/dma-helpers.c:129:9
    #15 in blk_aio_complete ../block/block-backend.c:1552:9
    #16 in blk_aio_write_entry ../block/block-backend.c:1619:5
    #17 in coroutine_trampoline ../util/coroutine-ucontext.c:175:9

Plug the leak by freeing the device path string.

Signed-off-by: Fabiano Rosas <farosas@suse.de>
---
 block/block-backend.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/block/block-backend.c b/block/block-backend.c
index 85bcdedcef..a3b7f00188 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -2134,13 +2134,14 @@ static void send_qmp_error_event(BlockBackend *blk,
 {
     IoOperationType optype;
     BlockDriverState *bs = blk_bs(blk);
+    char *path = blk_get_attached_dev_path(blk);
 
     optype = is_read ? IO_OPERATION_TYPE_READ : IO_OPERATION_TYPE_WRITE;
-    qapi_event_send_block_io_error(blk_name(blk),
-                                   blk_get_attached_dev_path(blk),
+    qapi_event_send_block_io_error(blk_name(blk), path,
                                    bs ? bdrv_get_node_name(bs) : NULL, optype,
                                    action, blk_iostatus_is_enabled(blk),
                                    error == ENOSPC, strerror(error));
+    g_free(path);
 }
 
 /* This is done by device models because, while the block layer knows
-- 
2.35.3