The patch titled
Subject: modules: wait do_free_init correctly
has been added to the -mm mm-nonmm-unstable branch. Its filename is
modules-wait-do_free_init-correctly.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/modules-wait-do_free_init-correctly.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Changbin Du <changbin.du@xxxxxxxxxx>
Subject: modules: wait do_free_init correctly
Date: Mon, 29 Jan 2024 10:03:04 +0800
commit 1a7b7d922081 ("modules: Use vmalloc special flag") moves
do_free_init() into a global workqueue instead of call_rcu(). So now
rcu_barrier() can not ensure that do_free_init has completed. We should
wait it via flush_work().
Without this fix, we still could encounter false positive reports in W+X
checking, and rcu synchronization is unnecessary.
Link: https://lkml.kernel.org/r/20240129020304.1981372-1-changbin.du@xxxxxxxxxx
Fixes: 1a7b7d922081 ("modules: Use vmalloc special flag")
Signed-off-by: Changbin Du <changbin.du@xxxxxxxxxx>
Cc: Xiaoyi Su <suxiaoyi@xxxxxxxxxx>
Cc: Luis Chamberlain <mcgrof@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/moduleloader.h | 8 ++++++++
init/main.c | 5 +++--
kernel/module/main.c | 5 +++++
3 files changed, 16 insertions(+), 2 deletions(-)
--- a/include/linux/moduleloader.h~modules-wait-do_free_init-correctly
+++ a/include/linux/moduleloader.h
@@ -115,6 +115,14 @@ int module_finalize(const Elf_Ehdr *hdr,
const Elf_Shdr *sechdrs,
struct module *mod);
+#ifdef CONFIG_MODULES
+void flush_module_init_free_work(void);
+#else
+static inline void flush_module_init_free_work(void)
+{
+}
+#endif
+
/* Any cleanup needed when module leaves. */
void module_arch_cleanup(struct module *mod);
--- a/init/main.c~modules-wait-do_free_init-correctly
+++ a/init/main.c
@@ -99,6 +99,7 @@
#include <linux/init_syscalls.h>
#include <linux/stackdepot.h>
#include <linux/randomize_kstack.h>
+#include <linux/moduleloader.h>
#include <net/net_namespace.h>
#include <asm/io.h>
@@ -1397,11 +1398,11 @@ static void mark_readonly(void)
if (rodata_enabled) {
/*
* load_module() results in W+X mappings, which are cleaned
- * up with call_rcu(). Let's make sure that queued work is
+ * up with init_free_wq. Let's make sure that queued work is
* flushed so that we don't hit false positives looking for
* insecure pages which are W+X.
*/
- rcu_barrier();
+ flush_module_init_free_work();
mark_rodata_ro();
rodata_test();
} else
--- a/kernel/module/main.c~modules-wait-do_free_init-correctly
+++ a/kernel/module/main.c
@@ -2489,6 +2489,11 @@ static void do_free_init(struct work_str
}
}
+void flush_module_init_free_work(void)
+{
+ flush_work(&init_free_wq);
+}
+
#undef MODULE_PARAM_PREFIX
#define MODULE_PARAM_PREFIX "module."
/* Default value for module->async_probe_requested */
_
Patches currently in -mm which might be from changbin.du@xxxxxxxxxx are
modules-wait-do_free_init-correctly.patch
