[PATCH 06/23] block/qed: add missing graph rdlock in qed_need_check_timer_entry

From: Kevin Wolf <kwolf@redhat.com>
To: qemu-block@nongnu.org
Cc: kwolf@redhat.com, pbonzini@redhat.com, stefanha@redhat.com,
	eesposit@redhat.com, qemu-devel@nongnu.org
Subject: [PATCH 06/23] block/qed: add missing graph rdlock in qed_need_check_timer_entry
Date: Fri,  3 Feb 2023 16:21:45 +0100	[thread overview]
Message-ID: <20230203152202.49054-7-kwolf@redhat.com> (raw)
In-Reply-To: <20230203152202.49054-1-kwolf@redhat.com>

From: Emanuele Giuseppe Esposito <eesposit@redhat.com>

This function is called in two different places:
- timer callback, which does not take the graph rdlock.
- bdrv_qed_drain_begin(), which is .bdrv_drain_begin()
  callback documented as function that does not take the lock.

Since it calls recursive functions that traverse the
graph, we need to protect them with the graph rdlock.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block/qed.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/block/qed.c b/block/qed.c
index 175a46c67b..7690d0215d 100644
--- a/block/qed.c
+++ b/block/qed.c
@@ -282,11 +282,12 @@ static void coroutine_fn qed_unplug_allocating_write_reqs(BDRVQEDState *s)
     qemu_co_mutex_unlock(&s->table_lock);
 }
 
-static void coroutine_fn qed_need_check_timer(BDRVQEDState *s)
+static void coroutine_fn GRAPH_RDLOCK qed_need_check_timer(BDRVQEDState *s)
 {
     int ret;
 
     trace_qed_need_check_timer_cb(s);
+    assert_bdrv_graph_readable();
 
     if (!qed_plug_allocating_write_reqs(s)) {
         return;
@@ -312,6 +313,7 @@ static void coroutine_fn qed_need_check_timer(BDRVQEDState *s)
 static void coroutine_fn qed_need_check_timer_entry(void *opaque)
 {
     BDRVQEDState *s = opaque;
+    GRAPH_RDLOCK_GUARD();
 
     qed_need_check_timer(opaque);
     bdrv_dec_in_flight(s->bs);
-- 
2.38.1


