From 5ee906eee3ec8f018a35777d72c146c08ad59e80 Mon Sep 17 00:00:00 2001
From: Red Bear OS <build@redbearos.org>
Date: Sun, 12 Jul 2026 11:31:34 +0300
Subject: [PATCH] fix: add MAP_SHARED to map_mut_anywhere flags

validate_kfmap_flags in kernel proc scheme requires exactly one of
MAP_SHARED or MAP_PRIVATE. Without it, shared == private == false,
and the check fails with EINVAL. This was the root cause of the
fexec_impl crash at step 62 (first PT_LOAD segment mapping).
---
 redox-rt/src/proc.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/redox-rt/src/proc.rs b/redox-rt/src/proc.rs
index de03a80b94..d24e66f9a8 100644
--- a/redox-rt/src/proc.rs
+++ b/redox-rt/src/proc.rs
@@ -740,7 +740,7 @@ impl<'a> MmapGuard<'a> {
                 size,
                 offset,
                 address: 0,
-                flags: PROT_READ | PROT_WRITE,
+                flags: PROT_READ | PROT_WRITE | MapFlags::MAP_SHARED,
             },
         )?;
         let slice = unsafe { &mut *this.as_mut_ptr_slice() };