From 081ff2651991a29973b214dbcffbca4326c4fd71 Mon Sep 17 00:00:00 2001
From: Christian Schwarz <christian@neon.tech>
Date: Mon, 20 Jan 2025 20:47:21 +0100
Subject: [PATCH] fixup 40ab9c2c5ee7c68f72cc5edadad7973995f5352f: deadlock

Reproduced by

test_runner/regress/test_branching.py::test_branching_with_pgbench[debug-pg16-flat-1-10]'

It kinda makes sense that this deadlocks in `sequential` mode.

However, it also deadlocks in `sidecar-task` mode.
I don't understand why.
---
 pageserver/src/tenant/storage_layer/inmemory_layer.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pageserver/src/tenant/storage_layer/inmemory_layer.rs b/pageserver/src/tenant/storage_layer/inmemory_layer.rs
index cc28e77278..d745ada6e7 100644
--- a/pageserver/src/tenant/storage_layer/inmemory_layer.rs
+++ b/pageserver/src/tenant/storage_layer/inmemory_layer.rs
@@ -470,7 +470,7 @@ impl InMemoryLayer {
                 }
             }
         }
-
+        drop(inner); // release the lock before we spawn the IO; if it's serial-mode IO we will deadlock on the read().await below
         let read_from = Arc::clone(self);
         let read_ctx = ctx.attached_child();
         reconstruct_state