From: Roman Kagan <rvka...@yandex-team.ru>
Simplify lifetime management of BDRVNBDState->connect_thread by
delaying the possible cleanup of it until the BDRVNBDState itself goes
away.
This also reverts
0267101af6 "block/nbd: fix possible use after free of s->connect_thread"
as now s->connect_thread can't be cleared until the very end.
Signed-off-by: Roman Kagan <rvka...@yandex-team.ru>
[vsementsov: rebase, revert 0267101af6 changes]
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com>
---
block/nbd.c | 56 ++++++++++++++++++++---------------------------------
1 file changed, 21 insertions(+), 35 deletions(-)
diff --git a/block/nbd.c b/block/nbd.c
index a407a3814b..272af60b44 100644
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -144,17 +144,31 @@ typedef struct BDRVNBDState {
NBDConnectThread *connect_thread;
} BDRVNBDState;
+static void nbd_free_connect_thread(NBDConnectThread *thr);
static int nbd_establish_connection(BlockDriverState *bs, SocketAddress *saddr,
Error **errp);
static int nbd_co_establish_connection(BlockDriverState *bs, Error **errp);
-static void nbd_co_establish_connection_cancel(BlockDriverState *bs,
- bool detach);
+static void nbd_co_establish_connection_cancel(BlockDriverState *bs);
static int nbd_client_handshake(BlockDriverState *bs, Error **errp);
static void nbd_yank(void *opaque);
static void nbd_clear_bdrvstate(BlockDriverState *bs)
{
BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
+ NBDConnectThread *thr = s->connect_thread;
+ bool thr_running;
+
+ qemu_mutex_lock(&thr->mutex);
+ thr_running = thr->state == CONNECT_THREAD_RUNNING;
+ if (thr_running) {
+ thr->state = CONNECT_THREAD_RUNNING_DETACHED;
+ }
+ qemu_mutex_unlock(&thr->mutex);
+
+ /* the runaway thread will clean it up itself */
+ if (!thr_running) {
+ nbd_free_connect_thread(thr);
+ }
yank_unregister_instance(BLOCKDEV_YANK_INSTANCE(bs->node_name));
@@ -297,7 +311,7 @@ static void coroutine_fn
nbd_client_co_drain_begin(BlockDriverState *bs)
qemu_co_sleep_wake(s->connection_co_sleep_ns_state);
}
- nbd_co_establish_connection_cancel(bs, false);
+ nbd_co_establish_connection_cancel(bs);
reconnect_delay_timer_del(s);
@@ -337,7 +351,7 @@ static void nbd_teardown_connection(BlockDriverState *bs)
if (s->connection_co_sleep_ns_state) {
qemu_co_sleep_wake(s->connection_co_sleep_ns_state);
}
- nbd_co_establish_connection_cancel(bs, true);
+ nbd_co_establish_connection_cancel(bs);
}
if (qemu_in_coroutine()) {
s->teardown_co = qemu_coroutine_self();
@@ -448,11 +462,6 @@ nbd_co_establish_connection(BlockDriverState *bs, Error
**errp)
BDRVNBDState *s = bs->opaque;
NBDConnectThread *thr = s->connect_thread;
- if (!thr) {
- /* detached */
- return -1;
- }
-
qemu_mutex_lock(&thr->mutex);
switch (thr->state) {
@@ -496,12 +505,6 @@ nbd_co_establish_connection(BlockDriverState *bs, Error
**errp)
s->wait_connect = true;
qemu_coroutine_yield();
- if (!s->connect_thread) {
- /* detached */
- return -1;
- }
- assert(thr == s->connect_thread);
-
qemu_mutex_lock(&thr->mutex);
switch (thr->state) {
@@ -549,18 +552,12 @@ nbd_co_establish_connection(BlockDriverState *bs, Error
**errp)
* nbd_co_establish_connection_cancel
* Cancel nbd_co_establish_connection asynchronously: it will finish soon, to
* allow drained section to begin.
- *
- * If detach is true, also cleanup the state (or if thread is running, move it
- * to CONNECT_THREAD_RUNNING_DETACHED state). s->connect_thread becomes NULL if
- * detach is true.
*/
-static void nbd_co_establish_connection_cancel(BlockDriverState *bs,
- bool detach)
+static void nbd_co_establish_connection_cancel(BlockDriverState *bs)
{
BDRVNBDState *s = bs->opaque;
NBDConnectThread *thr = s->connect_thread;
bool wake = false;
- bool do_free = false;
qemu_mutex_lock(&thr->mutex);
@@ -571,21 +568,10 @@ static void
nbd_co_establish_connection_cancel(BlockDriverState *bs,
s->wait_connect = false;
wake = true;
}
- if (detach) {
- thr->state = CONNECT_THREAD_RUNNING_DETACHED;
- s->connect_thread = NULL;
- }
- } else if (detach) {
- do_free = true;
}
qemu_mutex_unlock(&thr->mutex);
- if (do_free) {
- nbd_free_connect_thread(thr);
- s->connect_thread = NULL;
- }
-
if (wake) {
aio_co_wake(s->connection_co);
}
@@ -2306,6 +2292,8 @@ static int nbd_open(BlockDriverState *bs, QDict *options,
int flags,
goto fail;
}
+ nbd_init_connect_thread(s);
+
/*
* establish TCP connection, return error if it fails
* TODO: Configurable retry-until-timeout behaviour.
@@ -2322,8 +2310,6 @@ static int nbd_open(BlockDriverState *bs, QDict *options,
int flags,
/* successfully connected */
s->state = NBD_CLIENT_CONNECTED;
- nbd_init_connect_thread(s);
-
s->connection_co = qemu_coroutine_create(nbd_connection_entry, s);
bdrv_inc_in_flight(bs);
aio_co_schedule(bdrv_get_aio_context(bs), s->connection_co);
--
2.29.2
