From fc07fe652344f31f8dadb8e8f03dbc38228b745c Mon Sep 17 00:00:00 2001
From: xoviat <xoviat@users.noreply.github.com>
Date: Fri, 7 Aug 2026 14:41:01 -0500
Subject: [PATCH] stm32/gpio: disable flex borrow tracking

partially reverts #6454.
---
 embassy-stm32/src/gpio.rs           | 13 +++----------
 embassy-stm32/src/usart/buffered.rs |  9 ++++++++-
 2 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/embassy-stm32/src/gpio.rs b/embassy-stm32/src/gpio.rs
index ffc88aac5d..21d00988fd 100644
--- a/embassy-stm32/src/gpio.rs
+++ b/embassy-stm32/src/gpio.rs
@@ -18,7 +18,6 @@ use crate::peripherals;
 #[cfg_attr(feature = "defmt", derive(defmt::Format))]
 pub struct Flex<'d> {
     pub(crate) pin: Peri<'d, AnyPin>,
-    borrowed: bool,
 }
 
 impl<'d> Flex<'d> {
@@ -30,19 +29,17 @@ impl<'d> Flex<'d> {
     #[inline]
     pub fn new(pin: Peri<'d, impl Pin>) -> Self {
         // Pin will be in disconnected state.
-        Self {
-            pin: pin.into(),
-            borrowed: false,
-        }
+        Self { pin: pin.into() }
     }
 
     /// Reborrow into a "child" Flex.
     ///
     /// `self` will stay borrowed until the child Peripheral is dropped.
+    ///
+    /// When the child is dropped, the parent must call set_as to set the Mode again.
     pub fn reborrow(&mut self) -> Flex<'_> {
         Flex {
             pin: self.pin.reborrow(),
-            borrowed: true,
         }
     }
 
@@ -50,7 +47,6 @@ impl<'d> Flex<'d> {
     pub unsafe fn clone_unchecked(&self) -> Flex<'d> {
         Flex {
             pin: self.pin.clone_unchecked(),
-            borrowed: self.borrowed,
         }
     }
 
@@ -257,9 +253,6 @@ impl<'d> Flex<'d> {
 impl<'d> Drop for Flex<'d> {
     #[inline]
     fn drop(&mut self) {
-        if self.borrowed {
-            return;
-        }
         trace!("gpio: dropping {}", self.pin);
         critical_section::with(|_| {
             self.pin.set_as_disconnected();
diff --git a/embassy-stm32/src/usart/buffered.rs b/embassy-stm32/src/usart/buffered.rs
index 723ca59301..cc05baecb3 100644
--- a/embassy-stm32/src/usart/buffered.rs
+++ b/embassy-stm32/src/usart/buffered.rs
@@ -1,8 +1,8 @@
 use core::future::poll_fn;
 use core::marker::PhantomData;
-use core::slice;
 use core::sync::atomic::{AtomicBool, AtomicU8, AtomicUsize, Ordering};
 use core::task::Poll;
+use core::{mem, slice};
 
 use embassy_embedded_hal::SetConfig;
 use embassy_hal_internal::Peri;
@@ -869,6 +869,9 @@ impl<'d> Drop for BufferedUartRx<'d> {
             }
 
             drop_tx_rx(self.info, state);
+        } else {
+            mem::forget(self.rts.take());
+            mem::forget(self.rx.take());
         }
     }
 }
@@ -887,6 +890,10 @@ impl<'d> Drop for BufferedUartTx<'d> {
                 }
             }
             drop_tx_rx(self.info, state);
+        } else {
+            mem::forget(self.tx.take());
+            mem::forget(self.cts.take());
+            mem::forget(self.de.take());
         }
     }
 }