Force the linker not to drop jemalloc shim on Linux

cumulus/polkadot-omni-node/src/main.rs

@@ -21,6 +21,10 @@
 #![warn(missing_docs)]
 #![warn(unused_extern_crates)]
 
+// Force the linker to keep the polkadot_jemalloc_shim crate (and its #[global_allocator]).
+#[cfg(target_os = "linux")]
+extern crate polkadot_jemalloc_shim;
+
 use polkadot_omni_node_lib::{
 	chain_spec::DiskChainSpecLoader, extra_subcommand::NoExtraSubcommand, run_with_custom_cli,
 	runtime::DefaultRuntimeResolver, CliConfig as CliConfigT, RunConfig, NODE_VERSION,

cumulus/polkadot-parachain/src/main.rs

@@ -19,6 +19,10 @@
 #![warn(missing_docs)]
 #![warn(unused_extern_crates)]
 
+// Force the linker to keep the polkadot_jemalloc_shim crate (and its #[global_allocator]).
+#[cfg(target_os = "linux")]
+extern crate polkadot_jemalloc_shim;
+
 mod chain_spec;
 
 use polkadot_omni_node_lib::{

polkadot/src/main.rs

@@ -18,6 +18,10 @@
 
 #![warn(missing_docs)]
 
+// Force the linker to keep the polkadot_jemalloc_shim crate (and its #[global_allocator]).
+#[cfg(target_os = "linux")]
+extern crate polkadot_jemalloc_shim;
+
 use color_eyre::eyre;
 
 fn main() -> eyre::Result<()> {

prdoc/pr_11114.prdoc

@@ -0,0 +1,19 @@
+title: 'Force the linker not to drop jemalloc shim on Linux'
+doc:
+- audience: Runtime Dev
+  description: "Force the linker to keep the polkadot_jemalloc_shim crate and its\
+    \ #[global_allocator] in all binaries that depend on it. Without it, the linker\
+    \ might drop it since it is seen as a dependency with no referenced symbols.\
+    \ The issue happens only on a subset of combination of rust version and linker\
+    \ (e.g. on CI with Ubuntu 24.04, rust 1.88.0 + gcc/ld strips the jemalloc crate\
+    \ from the binary but not rust 1.92.0, and also rust 1.88.0 + clang/mold works\
+    \ fine).\n"
+crates:
+- name: frame-omni-bencher
+  bump: patch
+- name: polkadot
+  bump: patch
+- name: polkadot-parachain-bin
+  bump: patch
+- name: polkadot-omni-node
+  bump: patch

substrate/utils/frame/omni-bencher/src/main.rs

@@ -17,6 +17,10 @@
 
 mod command;
 
+// Force the linker to keep the polkadot_jemalloc_shim crate (and its #[global_allocator]).
+#[cfg(target_os = "linux")]
+extern crate polkadot_jemalloc_shim;
+
 use clap::Parser;
 use sc_cli::Result;
 use tracing_subscriber::EnvFilter;