From 8353d0d6a31042ba7c54696ef1ec59eb883d647f Mon Sep 17 00:00:00 2001 From: Zhang Bo Date: Mon, 29 Aug 2022 15:37:08 +0800 Subject: [PATCH 4/5] block/nbd: Assert there are no timers when closed Our two timers must not remain armed beyond nbd_clear_bdrvstate(), or they will access freed data when they fire. This patch is separate from the patches that actually fix the issue (HEAD^^ and HEAD^) so that you can run the associated regression iotest (281) on a configuration that reproducibly exposes the bug. Reviewed-by: Vladimir Sementsov-Ogievskiy Signed-off-by: Hanna Reitz Signed-off-by: Vladimir Sementsov-Ogievskiy Signed-off-by: Zhang Bo --- block/nbd.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/block/nbd.c b/block/nbd.c index 5ff8a57314..dc6c3f3bbc 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -110,6 +110,10 @@ static void nbd_clear_bdrvstate(BlockDriverState *bs) yank_unregister_instance(BLOCKDEV_YANK_INSTANCE(bs->node_name)); + /* Must not leave timers behind that would access freed data */ + assert(!s->reconnect_delay_timer); + assert(!s->open_timer); + object_unref(OBJECT(s->tlscreds)); qapi_free_SocketAddress(s->saddr); s->saddr = NULL; -- 2.27.0