+ kprobes-remove-dependency-on-config_modules.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

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The patch titled
     Subject: kprobes: remove dependency on CONFIG_MODULES
has been added to the -mm mm-unstable branch.  Its filename is
     kprobes-remove-dependency-on-config_modules.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/kprobes-remove-dependency-on-config_modules.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: "Mike Rapoport (IBM)" <rppt@kernel.org>
Subject: kprobes: remove dependency on CONFIG_MODULES
Date: Mon, 18 Sep 2023 10:29:54 +0300

kprobes depended on CONFIG_MODULES because it has to allocate memory for
code.

Since code allocations are now implemented with execmem, kprobes can be
enabled in non-modular kernels.

Add #ifdef CONFIG_MODULE guards for the code dealing with kprobes inside
modules, make CONFIG_KPROBES select CONFIG_EXECMEM and drop the dependency
of CONFIG_KPROBES on CONFIG_MODULES.

Link: https://lkml.kernel.org/r/20230918072955.2507221-13-rppt@kernel.org
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Björn Töpel <bjorn@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Puranjay Mohan <puranjay12@gmail.com>
Cc: Rick Edgecombe <rick.p.edgecombe@intel.com>
Cc: Russell King (Oracle) <linux@armlinux.org.uk>
Cc: Song Liu <song@kernel.org>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/Kconfig                |    2 -
 kernel/kprobes.c            |   43 +++++++++++++++++++---------------
 kernel/trace/trace_kprobe.c |   11 ++++++++
 3 files changed, 37 insertions(+), 19 deletions(-)

--- a/arch/Kconfig~kprobes-remove-dependency-on-config_modules
+++ a/arch/Kconfig
@@ -52,9 +52,9 @@ config GENERIC_ENTRY
 
 config KPROBES
 	bool "Kprobes"
-	depends on MODULES
 	depends on HAVE_KPROBES
 	select KALLSYMS
+	select EXECMEM
 	select TASKS_RCU if PREEMPTION
 	help
 	  Kprobes allows you to trap at almost any kernel address and
--- a/kernel/kprobes.c~kprobes-remove-dependency-on-config_modules
+++ a/kernel/kprobes.c
@@ -1580,6 +1580,7 @@ static int check_kprobe_address_safe(str
 		goto out;
 	}
 
+#ifdef CONFIG_MODULES
 	/* Check if 'p' is probing a module. */
 	*probed_mod = __module_text_address((unsigned long) p->addr);
 	if (*probed_mod) {
@@ -1603,6 +1604,8 @@ static int check_kprobe_address_safe(str
 			ret = -ENOENT;
 		}
 	}
+#endif
+
 out:
 	preempt_enable();
 	jump_label_unlock();
@@ -2495,24 +2498,6 @@ int kprobe_add_area_blacklist(unsigned l
 	return 0;
 }
 
-/* Remove all symbols in given area from kprobe blacklist */
-static void kprobe_remove_area_blacklist(unsigned long start, unsigned long end)
-{
-	struct kprobe_blacklist_entry *ent, *n;
-
-	list_for_each_entry_safe(ent, n, &kprobe_blacklist, list) {
-		if (ent->start_addr < start || ent->start_addr >= end)
-			continue;
-		list_del(&ent->list);
-		kfree(ent);
-	}
-}
-
-static void kprobe_remove_ksym_blacklist(unsigned long entry)
-{
-	kprobe_remove_area_blacklist(entry, entry + 1);
-}
-
 int __weak arch_kprobe_get_kallsym(unsigned int *symnum, unsigned long *value,
 				   char *type, char *sym)
 {
@@ -2577,6 +2562,25 @@ static int __init populate_kprobe_blackl
 	return ret ? : arch_populate_kprobe_blacklist();
 }
 
+#ifdef CONFIG_MODULES
+/* Remove all symbols in given area from kprobe blacklist */
+static void kprobe_remove_area_blacklist(unsigned long start, unsigned long end)
+{
+	struct kprobe_blacklist_entry *ent, *n;
+
+	list_for_each_entry_safe(ent, n, &kprobe_blacklist, list) {
+		if (ent->start_addr < start || ent->start_addr >= end)
+			continue;
+		list_del(&ent->list);
+		kfree(ent);
+	}
+}
+
+static void kprobe_remove_ksym_blacklist(unsigned long entry)
+{
+	kprobe_remove_area_blacklist(entry, entry + 1);
+}
+
 static void add_module_kprobe_blacklist(struct module *mod)
 {
 	unsigned long start, end;
@@ -2678,6 +2682,7 @@ static struct notifier_block kprobe_modu
 	.notifier_call = kprobes_module_callback,
 	.priority = 0
 };
+#endif
 
 void kprobe_free_init_mem(void)
 {
@@ -2737,8 +2742,10 @@ static int __init init_kprobes(void)
 	err = arch_init_kprobes();
 	if (!err)
 		err = register_die_notifier(&kprobe_exceptions_nb);
+#ifdef CONFIG_MODULES
 	if (!err)
 		err = register_module_notifier(&kprobe_module_nb);
+#endif
 
 	kprobes_initialized = (err == 0);
 	kprobe_sysctls_init();
--- a/kernel/trace/trace_kprobe.c~kprobes-remove-dependency-on-config_modules
+++ a/kernel/trace/trace_kprobe.c
@@ -111,6 +111,7 @@ static nokprobe_inline bool trace_kprobe
 	return strncmp(module_name(mod), name, len) == 0 && name[len] == ':';
 }
 
+#ifdef CONFIG_MODULES
 static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
 {
 	char *p;
@@ -129,6 +130,12 @@ static nokprobe_inline bool trace_kprobe
 
 	return ret;
 }
+#else
+static inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
+{
+	return false;
+}
+#endif
 
 static bool trace_kprobe_is_busy(struct dyn_event *ev)
 {
@@ -670,6 +677,7 @@ end:
 	return ret;
 }
 
+#ifdef CONFIG_MODULES
 /* Module notifier call back, checking event on the module */
 static int trace_kprobe_module_callback(struct notifier_block *nb,
 				       unsigned long val, void *data)
@@ -704,6 +712,7 @@ static struct notifier_block trace_kprob
 	.notifier_call = trace_kprobe_module_callback,
 	.priority = 1	/* Invoked after kprobe module callback */
 };
+#endif
 
 static int __trace_kprobe_create(int argc, const char *argv[])
 {
@@ -1810,8 +1819,10 @@ static __init int init_kprobe_trace_earl
 	if (ret)
 		return ret;
 
+#ifdef CONFIG_MODULES
 	if (register_module_notifier(&trace_kprobe_module_nb))
 		return -EINVAL;
+#endif
 
 	return 0;
 }
_

Patches currently in -mm which might be from rppt@kernel.org are

nios2-define-virtual-address-space-for-modules.patch
mm-introduce-execmem_text_alloc-and-execmem_free.patch
mm-execmem-arch-convert-simple-overrides-of-module_alloc-to-execmem.patch
mm-execmem-arch-convert-remaining-overrides-of-module_alloc-to-execmem.patch
modules-execmem-drop-module_alloc.patch
mm-execmem-introduce-execmem_data_alloc.patch
arm64-execmem-extend-execmem_params-for-generated-code-allocations.patch
riscv-extend-execmem_params-for-generated-code-allocations.patch
powerpc-extend-execmem_params-for-kprobes-allocations.patch
arch-make-execmem-setup-available-regardless-of-config_modules.patch
x86-ftrace-enable-dynamic-ftrace-without-config_modules.patch
kprobes-remove-dependency-on-config_modules.patch
bpf-remove-config_bpf_jit-dependency-on-config_modules-of.patch