diff --git a/aya/src/lib.rs b/aya/src/lib.rs
index 75451e25..eca3d072 100644
--- a/aya/src/lib.rs
+++ b/aya/src/lib.rs
@@ -97,37 +97,44 @@ pub use object::Endianness;
 pub use sys::netlink_set_link_up;
 
 // See https://github.com/rust-lang/rust/pull/124210; this structure exists to avoid crashing the
-// process when we try to close a fake file descriptor in Miri.
+// process when we try to close a fake file descriptor.
 #[derive(Debug)]
-struct MiriSafeFd {
-    #[cfg(not(miri))]
+struct MockableFd {
+    #[cfg(not(test))]
     fd: OwnedFd,
-    #[cfg(miri)]
+    #[cfg(test)]
     fd: Option<OwnedFd>,
 }
 
-impl MiriSafeFd {
-    #[cfg(any(test, miri))]
-    const MOCK_FD: u16 = 1337;
+impl MockableFd {
+    #[cfg(test)]
+    const fn mock_signed_fd() -> i32 {
+        1337
+    }
+
+    #[cfg(test)]
+    const fn mock_unsigned_fd() -> u32 {
+        1337
+    }
 
-    #[cfg(not(miri))]
+    #[cfg(not(test))]
     fn from_fd(fd: OwnedFd) -> Self {
         Self { fd }
     }
 
-    #[cfg(miri)]
+    #[cfg(test)]
     fn from_fd(fd: OwnedFd) -> Self {
         Self { fd: Some(fd) }
     }
 
-    #[cfg(not(miri))]
+    #[cfg(not(test))]
     fn try_clone(&self) -> std::io::Result<Self> {
         let Self { fd } = self;
         let fd = fd.try_clone()?;
         Ok(Self { fd })
     }
 
-    #[cfg(miri)]
+    #[cfg(test)]
     fn try_clone(&self) -> std::io::Result<Self> {
         let Self { fd } = self;
         let fd = fd.as_ref().map(OwnedFd::try_clone).transpose()?;
@@ -135,33 +142,34 @@ impl MiriSafeFd {
     }
 }
 
-impl AsFd for MiriSafeFd {
-    #[cfg(not(miri))]
+impl AsFd for MockableFd {
+    #[cfg(not(test))]
     fn as_fd(&self) -> BorrowedFd<'_> {
         let Self { fd } = self;
         fd.as_fd()
     }
 
-    #[cfg(miri)]
+    #[cfg(test)]
     fn as_fd(&self) -> BorrowedFd<'_> {
         let Self { fd } = self;
         fd.as_ref().unwrap().as_fd()
     }
 }
 
-impl Drop for MiriSafeFd {
-    #[cfg(not(miri))]
+impl Drop for MockableFd {
+    #[cfg(not(test))]
     fn drop(&mut self) {
         // Intentional no-op.
     }
 
-    #[cfg(miri)]
+    #[cfg(test)]
     fn drop(&mut self) {
         use std::os::fd::AsRawFd as _;
 
         let Self { fd } = self;
-        let fd = fd.take().unwrap();
-        assert_eq!(fd.as_raw_fd(), Self::MOCK_FD.into());
-        std::mem::forget(fd)
+        if fd.as_ref().unwrap().as_raw_fd() >= Self::mock_signed_fd() {
+            let fd: OwnedFd = fd.take().unwrap();
+            std::mem::forget(fd)
+        }
     }
 }
diff --git a/aya/src/maps/bloom_filter.rs b/aya/src/maps/bloom_filter.rs
index 14aef4d3..944f3f76 100644
--- a/aya/src/maps/bloom_filter.rs
+++ b/aya/src/maps/bloom_filter.rs
@@ -79,7 +79,7 @@ impl<T: BorrowMut<MapData>, V: Pod> BloomFilter<T, V> {
 
 #[cfg(test)]
 mod tests {
-    use std::{ffi::c_long, io};
+    use std::io;
 
     use assert_matches::assert_matches;
     use libc::{EFAULT, ENOENT};
@@ -102,7 +102,7 @@ mod tests {
         test_utils::new_obj_map::<u32>(BPF_MAP_TYPE_BLOOM_FILTER)
     }
 
-    fn sys_error(value: i32) -> SysResult<c_long> {
+    fn sys_error(value: i32) -> SysResult<i64> {
         Err((-1, io::Error::from_raw_os_error(value)))
     }
 
diff --git a/aya/src/maps/hash_map/hash_map.rs b/aya/src/maps/hash_map/hash_map.rs
index 307d1a51..becac6c4 100644
--- a/aya/src/maps/hash_map/hash_map.rs
+++ b/aya/src/maps/hash_map/hash_map.rs
@@ -103,7 +103,7 @@ impl<T: Borrow<MapData>, K: Pod, V: Pod> IterableMap<K, V> for HashMap<T, K, V>
 
 #[cfg(test)]
 mod tests {
-    use std::{ffi::c_long, io};
+    use std::io;
 
     use assert_matches::assert_matches;
     use libc::{EFAULT, ENOENT};
@@ -126,7 +126,7 @@ mod tests {
         test_utils::new_obj_map::<u32>(BPF_MAP_TYPE_HASH)
     }
 
-    fn sys_error(value: i32) -> SysResult<c_long> {
+    fn sys_error(value: i32) -> SysResult<i64> {
         Err((-1, io::Error::from_raw_os_error(value)))
     }
 
@@ -332,7 +332,7 @@ mod tests {
         assert_matches!(keys, Ok(ks) if ks.is_empty())
     }
 
-    fn get_next_key(attr: &bpf_attr) -> SysResult<c_long> {
+    fn get_next_key(attr: &bpf_attr) -> SysResult<i64> {
         match bpf_key(attr) {
             None => set_next_key(attr, 10),
             Some(10) => set_next_key(attr, 20),
@@ -344,7 +344,7 @@ mod tests {
         Ok(1)
     }
 
-    fn lookup_elem(attr: &bpf_attr) -> SysResult<c_long> {
+    fn lookup_elem(attr: &bpf_attr) -> SysResult<i64> {
         match bpf_key(attr) {
             Some(10) => set_ret(attr, 100),
             Some(20) => set_ret(attr, 200),
diff --git a/aya/src/maps/lpm_trie.rs b/aya/src/maps/lpm_trie.rs
index 8e25ddd5..e2271908 100644
--- a/aya/src/maps/lpm_trie.rs
+++ b/aya/src/maps/lpm_trie.rs
@@ -196,7 +196,7 @@ impl<T: Borrow<MapData>, K: Pod, V: Pod> IterableMap<Key<K>, V> for LpmTrie<T, K
 
 #[cfg(test)]
 mod tests {
-    use std::{ffi::c_long, io, net::Ipv4Addr};
+    use std::{io, net::Ipv4Addr};
 
     use assert_matches::assert_matches;
     use libc::{EFAULT, ENOENT};
@@ -219,7 +219,7 @@ mod tests {
         test_utils::new_obj_map::<Key<u32>>(BPF_MAP_TYPE_LPM_TRIE)
     }
 
-    fn sys_error(value: i32) -> SysResult<c_long> {
+    fn sys_error(value: i32) -> SysResult<i64> {
         Err((-1, io::Error::from_raw_os_error(value)))
     }
 
diff --git a/aya/src/maps/mod.rs b/aya/src/maps/mod.rs
index 7abdabba..82467aee 100644
--- a/aya/src/maps/mod.rs
+++ b/aya/src/maps/mod.rs
@@ -49,7 +49,7 @@
 //! implement the [Pod] trait.
 use std::{
     borrow::Borrow,
-    ffi::{c_long, CString},
+    ffi::CString,
     fmt, io,
     marker::PhantomData,
     mem,
@@ -127,7 +127,7 @@ pub enum MapError {
         /// Map name
         name: String,
         /// Error code
-        code: c_long,
+        code: i64,
         #[source]
         /// Original io::Error
         io_error: io::Error,
@@ -211,12 +211,12 @@ impl From<InvalidMapTypeError> for MapError {
 /// A map file descriptor.
 #[derive(Debug)]
 pub struct MapFd {
-    fd: crate::MiriSafeFd,
+    fd: crate::MockableFd,
 }
 
 impl MapFd {
     fn from_fd(fd: OwnedFd) -> Self {
-        let fd = crate::MiriSafeFd::from_fd(fd);
+        let fd = crate::MockableFd::from_fd(fd);
         Self { fd }
     }
 
@@ -1052,7 +1052,7 @@ mod test_utils {
             Syscall::Ebpf {
                 cmd: bpf_cmd::BPF_MAP_CREATE,
                 ..
-            } => Ok(crate::MiriSafeFd::MOCK_FD.into()),
+            } => Ok(crate::MockableFd::mock_signed_fd().into()),
             call => panic!("unexpected syscall {:?}", call),
         });
         MapData::create(obj, "foo", None).unwrap()
@@ -1103,7 +1103,7 @@ mod tests {
                     unsafe { attr.__bindgen_anon_6.__bindgen_anon_1.map_id },
                     1234
                 );
-                Ok(crate::MiriSafeFd::MOCK_FD.into())
+                Ok(crate::MockableFd::mock_signed_fd().into())
             }
             Syscall::Ebpf {
                 cmd: bpf_cmd::BPF_OBJ_GET_INFO_BY_FD,
@@ -1111,7 +1111,7 @@ mod tests {
             } => {
                 assert_eq!(
                     unsafe { attr.info.bpf_fd },
-                    crate::MiriSafeFd::MOCK_FD.into()
+                    crate::MockableFd::mock_unsigned_fd(),
                 );
                 Ok(0)
             }
@@ -1123,7 +1123,7 @@ mod tests {
             Ok(MapData {
                 obj: _,
                 fd,
-            }) => assert_eq!(fd.as_fd().as_raw_fd(), crate::MiriSafeFd::MOCK_FD.into())
+            }) => assert_eq!(fd.as_fd().as_raw_fd(), crate::MockableFd::mock_signed_fd())
         );
     }
 
@@ -1133,7 +1133,7 @@ mod tests {
             Syscall::Ebpf {
                 cmd: bpf_cmd::BPF_MAP_CREATE,
                 ..
-            } => Ok(crate::MiriSafeFd::MOCK_FD.into()),
+            } => Ok(crate::MockableFd::mock_signed_fd().into()),
             _ => Err((-1, io::Error::from_raw_os_error(EFAULT))),
         });
 
@@ -1142,7 +1142,7 @@ mod tests {
             Ok(MapData {
                 obj: _,
                 fd,
-            }) => assert_eq!(fd.as_fd().as_raw_fd(), crate::MiriSafeFd::MOCK_FD.into())
+            }) => assert_eq!(fd.as_fd().as_raw_fd(), crate::MockableFd::mock_signed_fd())
         );
     }
 
@@ -1160,7 +1160,7 @@ mod tests {
             Syscall::Ebpf {
                 cmd: bpf_cmd::BPF_MAP_CREATE,
                 ..
-            } => Ok(42),
+            } => Ok(crate::MockableFd::mock_signed_fd().into()),
             Syscall::Ebpf {
                 cmd: bpf_cmd::BPF_OBJ_GET_INFO_BY_FD,
                 attr,
@@ -1206,13 +1206,15 @@ mod tests {
             Syscall::Ebpf {
                 cmd: bpf_cmd::BPF_MAP_GET_FD_BY_ID,
                 attr,
-            } => Ok((1000 + unsafe { attr.__bindgen_anon_6.__bindgen_anon_1.map_id }) as c_long),
+            } => Ok((unsafe { attr.__bindgen_anon_6.__bindgen_anon_1.map_id }
+                + crate::MockableFd::mock_unsigned_fd())
+            .into()),
             Syscall::Ebpf {
                 cmd: bpf_cmd::BPF_OBJ_GET_INFO_BY_FD,
                 attr,
             } => {
                 let map_info = unsafe { &mut *(attr.info.info as *mut bpf_map_info) };
-                map_info.id = unsafe { attr.info.bpf_fd } - 1000;
+                map_info.id = unsafe { attr.info.bpf_fd } - crate::MockableFd::mock_unsigned_fd();
                 map_info.key_size = 32;
                 map_info.value_size = 64;
                 map_info.map_flags = 1234;
@@ -1222,19 +1224,31 @@ mod tests {
             _ => Err((-1, io::Error::from_raw_os_error(EFAULT))),
         });
 
-        let loaded_maps: Vec<_> = loaded_maps().collect();
-        assert_eq!(loaded_maps.len(), 5);
-
-        for (i, map_info) in loaded_maps.into_iter().enumerate() {
-            let i = i + 1;
-            let map_info = map_info.unwrap();
-            assert_eq!(map_info.id(), i as u32);
-            assert_eq!(map_info.key_size(), 32);
-            assert_eq!(map_info.value_size(), 64);
-            assert_eq!(map_info.map_flags(), 1234);
-            assert_eq!(map_info.max_entries(), 99);
-            assert_eq!(map_info.fd().unwrap().as_fd().as_raw_fd(), 1000 + i as i32);
-        }
+        assert_eq!(
+            loaded_maps()
+                .map(|map_info| {
+                    let map_info = map_info.unwrap();
+                    (
+                        map_info.id(),
+                        map_info.key_size(),
+                        map_info.value_size(),
+                        map_info.map_flags(),
+                        map_info.max_entries(),
+                        map_info.fd().unwrap().as_fd().as_raw_fd(),
+                    )
+                })
+                .collect::<Vec<_>>(),
+            (1..6)
+                .map(|i: u8| (
+                    i.into(),
+                    32,
+                    64,
+                    1234,
+                    99,
+                    crate::MockableFd::mock_signed_fd() + i32::from(i)
+                ))
+                .collect::<Vec<_>>(),
+        );
     }
 
     #[test]
diff --git a/aya/src/maps/perf/perf_buffer.rs b/aya/src/maps/perf/perf_buffer.rs
index 26f09b20..89f2cf73 100644
--- a/aya/src/maps/perf/perf_buffer.rs
+++ b/aya/src/maps/perf/perf_buffer.rs
@@ -88,7 +88,7 @@ pub(crate) struct PerfBuffer {
     buf: AtomicPtr<perf_event_mmap_page>,
     size: usize,
     page_size: usize,
-    fd: crate::MiriSafeFd,
+    fd: crate::MockableFd,
 }
 
 impl PerfBuffer {
@@ -120,7 +120,7 @@ impl PerfBuffer {
             });
         }
 
-        let fd = crate::MiriSafeFd::from_fd(fd);
+        let fd = crate::MockableFd::from_fd(fd);
         let perf_buf = Self {
             buf: AtomicPtr::new(buf as *mut perf_event_mmap_page),
             size,
@@ -303,7 +303,7 @@ mod tests {
     fn fake_mmap(buf: &MMappedBuf) {
         override_syscall(|call| match call {
             Syscall::PerfEventOpen { .. } | Syscall::PerfEventIoctl { .. } => {
-                Ok(crate::MiriSafeFd::MOCK_FD.into())
+                Ok(crate::MockableFd::mock_signed_fd().into())
             }
             call => panic!("unexpected syscall: {:?}", call),
         });
diff --git a/aya/src/sys/bpf.rs b/aya/src/sys/bpf.rs
index add46b67..1ae1dc95 100644
--- a/aya/src/sys/bpf.rs
+++ b/aya/src/sys/bpf.rs
@@ -1,6 +1,6 @@
 use std::{
     cmp,
-    ffi::{c_char, c_long, CStr, CString},
+    ffi::{c_char, CStr, CString},
     io, iter,
     mem::{self, MaybeUninit},
     os::fd::{AsFd as _, AsRawFd as _, BorrowedFd, FromRawFd as _, OwnedFd, RawFd},
@@ -96,7 +96,7 @@ pub(crate) fn bpf_create_map(
     unsafe { fd_sys_bpf(bpf_cmd::BPF_MAP_CREATE, &mut attr) }
 }
 
-pub(crate) fn bpf_pin_object(fd: BorrowedFd<'_>, path: &CStr) -> SysResult<c_long> {
+pub(crate) fn bpf_pin_object(fd: BorrowedFd<'_>, path: &CStr) -> SysResult<i64> {
     let mut attr = unsafe { mem::zeroed::<bpf_attr>() };
     let u = unsafe { &mut attr.__bindgen_anon_4 };
     u.bpf_fd = fd.as_raw_fd() as u32;
@@ -200,7 +200,7 @@ fn lookup<K: Pod, V: Pod>(
     key: Option<&K>,
     flags: u64,
     cmd: bpf_cmd,
-) -> Result<Option<V>, (c_long, io::Error)> {
+) -> SysResult<Option<V>> {
     let mut attr = unsafe { mem::zeroed::<bpf_attr>() };
     let mut value = MaybeUninit::zeroed();
 
@@ -223,7 +223,7 @@ pub(crate) fn bpf_map_lookup_elem<K: Pod, V: Pod>(
     fd: BorrowedFd<'_>,
     key: &K,
     flags: u64,
-) -> Result<Option<V>, (c_long, io::Error)> {
+) -> SysResult<Option<V>> {
     lookup(fd, Some(key), flags, bpf_cmd::BPF_MAP_LOOKUP_ELEM)
 }
 
@@ -231,7 +231,7 @@ pub(crate) fn bpf_map_lookup_and_delete_elem<K: Pod, V: Pod>(
     fd: BorrowedFd<'_>,
     key: Option<&K>,
     flags: u64,
-) -> Result<Option<V>, (c_long, io::Error)> {
+) -> SysResult<Option<V>> {
     lookup(fd, key, flags, bpf_cmd::BPF_MAP_LOOKUP_AND_DELETE_ELEM)
 }
 
@@ -239,7 +239,7 @@ pub(crate) fn bpf_map_lookup_elem_per_cpu<K: Pod, V: Pod>(
     fd: BorrowedFd<'_>,
     key: &K,
     flags: u64,
-) -> Result<Option<PerCpuValues<V>>, (c_long, io::Error)> {
+) -> SysResult<Option<PerCpuValues<V>>> {
     let mut mem = PerCpuValues::<V>::alloc_kernel_mem().map_err(|io_error| (-1, io_error))?;
     match bpf_map_lookup_elem_ptr(fd, Some(key), mem.as_mut_ptr(), flags) {
         Ok(_) => Ok(Some(unsafe { PerCpuValues::from_kernel_mem(mem) })),
@@ -253,7 +253,7 @@ pub(crate) fn bpf_map_lookup_elem_ptr<K: Pod, V>(
     key: Option<&K>,
     value: *mut V,
     flags: u64,
-) -> Result<Option<()>, (c_long, io::Error)> {
+) -> SysResult<Option<()>> {
     let mut attr = unsafe { mem::zeroed::<bpf_attr>() };
 
     let u = unsafe { &mut attr.__bindgen_anon_2 };
@@ -276,7 +276,7 @@ pub(crate) fn bpf_map_update_elem<K: Pod, V: Pod>(
     key: Option<&K>,
     value: &V,
     flags: u64,
-) -> SysResult<c_long> {
+) -> SysResult<i64> {
     let mut attr = unsafe { mem::zeroed::<bpf_attr>() };
 
     let u = unsafe { &mut attr.__bindgen_anon_2 };
@@ -294,7 +294,7 @@ pub(crate) fn bpf_map_push_elem<V: Pod>(
     fd: BorrowedFd<'_>,
     value: &V,
     flags: u64,
-) -> SysResult<c_long> {
+) -> SysResult<i64> {
     let mut attr = unsafe { mem::zeroed::<bpf_attr>() };
 
     let u = unsafe { &mut attr.__bindgen_anon_2 };
@@ -310,7 +310,7 @@ pub(crate) fn bpf_map_update_elem_ptr<K, V>(
     key: *const K,
     value: *mut V,
     flags: u64,
-) -> SysResult<c_long> {
+) -> SysResult<i64> {
     let mut attr = unsafe { mem::zeroed::<bpf_attr>() };
 
     let u = unsafe { &mut attr.__bindgen_anon_2 };
@@ -327,12 +327,12 @@ pub(crate) fn bpf_map_update_elem_per_cpu<K: Pod, V: Pod>(
     key: &K,
     values: &PerCpuValues<V>,
     flags: u64,
-) -> SysResult<c_long> {
+) -> SysResult<i64> {
     let mut mem = values.build_kernel_mem().map_err(|e| (-1, e))?;
     bpf_map_update_elem_ptr(fd, key, mem.as_mut_ptr(), flags)
 }
 
-pub(crate) fn bpf_map_delete_elem<K: Pod>(fd: BorrowedFd<'_>, key: &K) -> SysResult<c_long> {
+pub(crate) fn bpf_map_delete_elem<K: Pod>(fd: BorrowedFd<'_>, key: &K) -> SysResult<i64> {
     let mut attr = unsafe { mem::zeroed::<bpf_attr>() };
 
     let u = unsafe { &mut attr.__bindgen_anon_2 };
@@ -345,7 +345,7 @@ pub(crate) fn bpf_map_delete_elem<K: Pod>(fd: BorrowedFd<'_>, key: &K) -> SysRes
 pub(crate) fn bpf_map_get_next_key<K: Pod>(
     fd: BorrowedFd<'_>,
     key: Option<&K>,
-) -> Result<Option<K>, (c_long, io::Error)> {
+) -> SysResult<Option<K>> {
     let mut attr = unsafe { mem::zeroed::<bpf_attr>() };
     let mut next_key = MaybeUninit::uninit();
 
@@ -364,7 +364,7 @@ pub(crate) fn bpf_map_get_next_key<K: Pod>(
 }
 
 // since kernel 5.2
-pub(crate) fn bpf_map_freeze(fd: BorrowedFd<'_>) -> SysResult<c_long> {
+pub(crate) fn bpf_map_freeze(fd: BorrowedFd<'_>) -> SysResult<i64> {
     let mut attr = unsafe { mem::zeroed::<bpf_attr>() };
     let u = unsafe { &mut attr.__bindgen_anon_2 };
     u.map_fd = fd.as_raw_fd() as u32;
@@ -412,7 +412,7 @@ pub(crate) fn bpf_link_update(
     new_prog_fd: BorrowedFd<'_>,
     old_prog_fd: Option<RawFd>,
     flags: u32,
-) -> SysResult<c_long> {
+) -> SysResult<i64> {
     let mut attr = unsafe { mem::zeroed::<bpf_attr>() };
 
     attr.link_update.link_fd = link_fd.as_raw_fd() as u32;
@@ -478,7 +478,7 @@ pub(crate) fn bpf_prog_query(
     attach_flags: Option<&mut u32>,
     prog_ids: &mut [u32],
     prog_cnt: &mut u32,
-) -> SysResult<c_long> {
+) -> SysResult<i64> {
     let mut attr = unsafe { mem::zeroed::<bpf_attr>() };
 
     attr.query.__bindgen_anon_1.target_fd = target_fd as u32;
@@ -730,7 +730,7 @@ pub(crate) fn is_perf_link_supported() -> bool {
     u.prog_type = bpf_prog_type::BPF_PROG_TYPE_TRACEPOINT as u32;
 
     if let Ok(fd) = bpf_prog_load(&mut attr) {
-        let fd = crate::MiriSafeFd::from_fd(fd);
+        let fd = crate::MockableFd::from_fd(fd);
         let fd = fd.as_fd();
         matches!(
             // Uses an invalid target FD so we get EBADF if supported.
@@ -830,7 +830,7 @@ pub(crate) fn is_prog_id_supported(map_type: bpf_map_type) -> bool {
 
     // SAFETY: BPF_MAP_CREATE returns a new file descriptor.
     let fd = unsafe { fd_sys_bpf(bpf_cmd::BPF_MAP_CREATE, &mut attr) };
-    let fd = fd.map(crate::MiriSafeFd::from_fd);
+    let fd = fd.map(crate::MockableFd::from_fd);
     fd.is_ok()
 }
 
@@ -995,7 +995,7 @@ fn bpf_prog_load(attr: &mut bpf_attr) -> SysResult<OwnedFd> {
     unsafe { fd_sys_bpf(bpf_cmd::BPF_PROG_LOAD, attr) }
 }
 
-fn sys_bpf(cmd: bpf_cmd, attr: &mut bpf_attr) -> SysResult<c_long> {
+fn sys_bpf(cmd: bpf_cmd, attr: &mut bpf_attr) -> SysResult<i64> {
     syscall(Syscall::Ebpf { cmd, attr })
 }
 
@@ -1103,7 +1103,7 @@ mod tests {
                 cmd: bpf_cmd::BPF_LINK_CREATE,
                 ..
             } => Err((-1, io::Error::from_raw_os_error(EBADF))),
-            _ => Ok(crate::MiriSafeFd::MOCK_FD.into()),
+            _ => Ok(crate::MockableFd::mock_signed_fd().into()),
         });
         let supported = is_perf_link_supported();
         assert!(supported);
@@ -1113,7 +1113,7 @@ mod tests {
                 cmd: bpf_cmd::BPF_LINK_CREATE,
                 ..
             } => Err((-1, io::Error::from_raw_os_error(EINVAL))),
-            _ => Ok(crate::MiriSafeFd::MOCK_FD.into()),
+            _ => Ok(crate::MockableFd::mock_signed_fd().into()),
         });
         let supported = is_perf_link_supported();
         assert!(!supported);
@@ -1121,7 +1121,7 @@ mod tests {
 
     #[test]
     fn test_prog_id_supported() {
-        override_syscall(|_call| Ok(crate::MiriSafeFd::MOCK_FD.into()));
+        override_syscall(|_call| Ok(crate::MockableFd::mock_signed_fd().into()));
 
         // Ensure that the three map types we can check are accepted
         let supported = is_prog_id_supported(bpf_map_type::BPF_MAP_TYPE_CPUMAP);
diff --git a/aya/src/sys/fake.rs b/aya/src/sys/fake.rs
index 47019926..0e0cd3fe 100644
--- a/aya/src/sys/fake.rs
+++ b/aya/src/sys/fake.rs
@@ -1,12 +1,8 @@
-use std::{
-    cell::RefCell,
-    ffi::{c_long, c_void},
-    io, ptr,
-};
+use std::{cell::RefCell, ffi::c_void, io, ptr};
 
 use super::{SysResult, Syscall};
 
-type SyscallFn = unsafe fn(Syscall<'_>) -> SysResult<c_long>;
+type SyscallFn = unsafe fn(Syscall<'_>) -> SysResult<i64>;
 
 #[cfg(test)]
 thread_local! {
@@ -15,11 +11,11 @@ thread_local! {
 }
 
 #[cfg(test)]
-unsafe fn test_syscall(_call: Syscall<'_>) -> SysResult<c_long> {
+unsafe fn test_syscall(_call: Syscall<'_>) -> SysResult<i64> {
     Err((-1, io::Error::from_raw_os_error(libc::EINVAL)))
 }
 
 #[cfg(test)]
-pub(crate) fn override_syscall(call: unsafe fn(Syscall<'_>) -> SysResult<c_long>) {
+pub(crate) fn override_syscall(call: unsafe fn(Syscall<'_>) -> SysResult<i64>) {
     TEST_SYSCALL.with(|test_impl| *test_impl.borrow_mut() = call);
 }
diff --git a/aya/src/sys/mod.rs b/aya/src/sys/mod.rs
index fddab712..1f13df5a 100644
--- a/aya/src/sys/mod.rs
+++ b/aya/src/sys/mod.rs
@@ -6,7 +6,7 @@ mod perf_event;
 mod fake;
 
 use std::{
-    ffi::{c_int, c_long, c_void},
+    ffi::{c_int, c_void},
     io, mem,
     os::fd::{AsRawFd as _, BorrowedFd},
 };
@@ -23,7 +23,7 @@ use thiserror::Error;
 
 use crate::generated::{bpf_attr, bpf_cmd, perf_event_attr};
 
-pub(crate) type SysResult<T> = Result<T, (c_long, io::Error)>;
+pub(crate) type SysResult<T> = Result<T, (i64, io::Error)>;
 
 pub(crate) enum Syscall<'a> {
     Ebpf {
@@ -86,33 +86,39 @@ impl std::fmt::Debug for Syscall<'_> {
     }
 }
 
-fn syscall(call: Syscall<'_>) -> SysResult<c_long> {
+fn syscall(call: Syscall<'_>) -> SysResult<i64> {
     #[cfg(test)]
     return TEST_SYSCALL.with(|test_impl| unsafe { test_impl.borrow()(call) });
 
     #[cfg_attr(test, allow(unreachable_code))]
-    match unsafe {
-        match call {
-            Syscall::Ebpf { cmd, attr } => {
-                libc::syscall(SYS_bpf, cmd, attr, mem::size_of::<bpf_attr>())
-            }
-            Syscall::PerfEventOpen {
-                attr,
-                pid,
-                cpu,
-                group,
-                flags,
-            } => libc::syscall(SYS_perf_event_open, &attr, pid, cpu, group, flags),
-            Syscall::PerfEventIoctl { fd, request, arg } => {
-                let int = libc::ioctl(fd.as_raw_fd(), request.try_into().unwrap(), arg);
-                #[allow(trivial_numeric_casts)]
-                let int = int as c_long;
-                int
+    {
+        let ret = unsafe {
+            match call {
+                Syscall::Ebpf { cmd, attr } => {
+                    libc::syscall(SYS_bpf, cmd, attr, mem::size_of::<bpf_attr>())
+                }
+                Syscall::PerfEventOpen {
+                    attr,
+                    pid,
+                    cpu,
+                    group,
+                    flags,
+                } => libc::syscall(SYS_perf_event_open, &attr, pid, cpu, group, flags),
+                Syscall::PerfEventIoctl { fd, request, arg } => {
+                    let ret = libc::ioctl(fd.as_raw_fd(), request.try_into().unwrap(), arg);
+                    // `libc::ioctl` returns i32 on x86_64 while `libc::syscall` returns i64.
+                    #[allow(clippy::useless_conversion)]
+                    ret.into()
+                }
             }
+        };
+
+        // `libc::syscall` returns i32 on armv7.
+        #[allow(clippy::useless_conversion)]
+        match ret.into() {
+            ret @ 0.. => Ok(ret),
+            ret => Err((ret, io::Error::last_os_error())),
         }
-    } {
-        ret @ 0.. => Ok(ret),
-        ret => Err((ret, io::Error::last_os_error())),
     }
 }
 
diff --git a/aya/src/sys/perf_event.rs b/aya/src/sys/perf_event.rs
index 1d7af608..f5815226 100644
--- a/aya/src/sys/perf_event.rs
+++ b/aya/src/sys/perf_event.rs
@@ -1,5 +1,5 @@
 use std::{
-    ffi::{c_int, c_long, CString, OsStr},
+    ffi::{c_int, CString, OsStr},
     io, mem,
     os::fd::{BorrowedFd, FromRawFd as _, OwnedFd},
 };
@@ -101,11 +101,7 @@ pub(crate) fn perf_event_open_trace_point(id: u32, pid: Option<pid_t>) -> SysRes
     perf_event_sys(attr, pid, cpu, PERF_FLAG_FD_CLOEXEC)
 }
 
-pub(crate) fn perf_event_ioctl(
-    fd: BorrowedFd<'_>,
-    request: c_int,
-    arg: c_int,
-) -> SysResult<c_long> {
+pub(crate) fn perf_event_ioctl(fd: BorrowedFd<'_>, request: c_int, arg: c_int) -> SysResult<i64> {
     let call = Syscall::PerfEventIoctl { fd, request, arg };
     #[cfg(not(test))]
     return syscall(call);
diff --git a/xtask/public-api/aya.txt b/xtask/public-api/aya.txt
index 760c4e08..2496b411 100644
--- a/xtask/public-api/aya.txt
+++ b/xtask/public-api/aya.txt
@@ -1330,7 +1330,7 @@ impl<T> core::convert::From<T> for aya::maps::Map
 pub fn aya::maps::Map::from(t: T) -> T
 pub enum aya::maps::MapError
 pub aya::maps::MapError::CreateError
-pub aya::maps::MapError::CreateError::code: core::ffi::c_long
+pub aya::maps::MapError::CreateError::code: i64
 pub aya::maps::MapError::CreateError::io_error: std::io::error::Error
 pub aya::maps::MapError::CreateError::name: alloc::string::String
 pub aya::maps::MapError::ElementNotFound