1 files changed, 33 insertions, 1 deletions

diff --git a/util/async.c b/util/async.c
index 21016a1ac7..055070ffbd 100644
--- a/util/async.c
+++ b/util/async.c
@@ -65,6 +65,7 @@ struct QEMUBH {
     void *opaque;
     QSLIST_ENTRY(QEMUBH) next;
     unsigned flags;
+    MemReentrancyGuard *reentrancy_guard;
 };
 
 /* Called concurrently from any thread */
@@ -137,7 +138,7 @@ void aio_bh_schedule_oneshot_full(AioContext *ctx, QEMUBHFunc *cb,
 }
 
 QEMUBH *aio_bh_new_full(AioContext *ctx, QEMUBHFunc *cb, void *opaque,
-                        const char *name)
+                        const char *name, MemReentrancyGuard *reentrancy_guard)
 {
     QEMUBH *bh;
     bh = g_new(QEMUBH, 1);
@@ -146,13 +147,30 @@ QEMUBH *aio_bh_new_full(AioContext *ctx, QEMUBHFunc *cb, void *opaque,
         .cb = cb,
         .opaque = opaque,
         .name = name,
+        .reentrancy_guard = reentrancy_guard,
     };
     return bh;
 }
 
 void aio_bh_call(QEMUBH *bh)
 {
+    bool last_engaged_in_io = false;
+
+    /* Make a copy of the guard-pointer as cb may free the bh */
+    MemReentrancyGuard *reentrancy_guard = bh->reentrancy_guard;
+    if (reentrancy_guard) {
+        last_engaged_in_io = reentrancy_guard->engaged_in_io;
+        if (reentrancy_guard->engaged_in_io) {
+            trace_reentrant_aio(bh->ctx, bh->name);
+        }
+        reentrancy_guard->engaged_in_io = true;
+    }
+
     bh->cb(bh->opaque);
+
+    if (reentrancy_guard) {
+        reentrancy_guard->engaged_in_io = last_engaged_in_io;
+    }
 }
 
 /* Multiple occurrences of aio_bh_poll cannot be called concurrently. */
@@ -164,7 +182,21 @@ int aio_bh_poll(AioContext *ctx)
 
     /* Synchronizes with QSLIST_INSERT_HEAD_ATOMIC in aio_bh_enqueue().  */
     QSLIST_MOVE_ATOMIC(&slice.bh_list, &ctx->bh_list);
+
+    /*
+     * GCC13 [-Werror=dangling-pointer=] complains that the local variable
+     * 'slice' is being stored in the global 'ctx->bh_slice_list' but the
+     * list is emptied before this function returns.
+     */
+#if !defined(__clang__)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wpragmas"
+#pragma GCC diagnostic ignored "-Wdangling-pointer="
+#endif
     QSIMPLEQ_INSERT_TAIL(&ctx->bh_slice_list, &slice, next);
+#if !defined(__clang__)
+#pragma GCC diagnostic pop
+#endif
 
     while ((s = QSIMPLEQ_FIRST(&ctx->bh_slice_list))) {
         QEMUBH *bh;