Merge tag 'hardening-v5.19-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull hardening fixes from Kees Cook:

 - Correctly handle vm_map areas in hardened usercopy (Matthew Wilcox)

 - Adjust CFI RCU usage to avoid boot splats with cpuidle (Sami Tolvanen)

* tag 'hardening-v5.19-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  usercopy: Make usercopy resilient against ridiculously large copies
  usercopy: Cast pointer to an integer once
  usercopy: Handle vm_map_ram() areas
  cfi: Fix __cfi_slowpath_diag RCU usage with cpuidle

1 files changed, 16 insertions, 6 deletions

diff --git a/kernel/cfi.c b/kernel/cfi.c
index 9594cfd1cf2c..08102d19ec15 100644
--- a/kernel/cfi.c
+++ b/kernel/cfi.c
@@ -281,6 +281,8 @@ static inline cfi_check_fn find_module_check_fn(unsigned long ptr)
 static inline cfi_check_fn find_check_fn(unsigned long ptr)
 {
 	cfi_check_fn fn = NULL;
+	unsigned long flags;
+	bool rcu_idle;
 
 	if (is_kernel_text(ptr))
 		return __cfi_check;
@@ -290,13 +292,21 @@ static inline cfi_check_fn find_check_fn(unsigned long ptr)
 	 * the shadow and __module_address use RCU, so we need to wake it
 	 * up if necessary.
 	 */
-	RCU_NONIDLE({
-		if (IS_ENABLED(CONFIG_CFI_CLANG_SHADOW))
-			fn = find_shadow_check_fn(ptr);
+	rcu_idle = !rcu_is_watching();
+	if (rcu_idle) {
+		local_irq_save(flags);
+		rcu_irq_enter();
+	}
+
+	if (IS_ENABLED(CONFIG_CFI_CLANG_SHADOW))
+		fn = find_shadow_check_fn(ptr);
+	if (!fn)
+		fn = find_module_check_fn(ptr);
 
-		if (!fn)
-			fn = find_module_check_fn(ptr);
-	});
+	if (rcu_idle) {
+		rcu_irq_exit();
+		local_irq_restore(flags);
+	}
 
 	return fn;
 }