+ alloc_tag-add-sequence-number-for-module-and-iterator.patch added to mm-new branch

+ alloc_tag-add-sequence-number-for-module-and-iterator.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: alloc_tag: add sequence number for module and iterator
has been added to the -mm mm-new branch.  Its filename is
     alloc_tag-add-sequence-number-for-module-and-iterator.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/alloc_tag-add-sequence-number-for-module-and-iterator.patch

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

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
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fixup patches in mm-new.

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------------------------------------------------------
From: David Wang <00107082@163.com>
Subject: alloc_tag: add sequence number for module and iterator
Date: Mon, 9 Jun 2025 14:42:00 +0800

Codetag iterator use <id,address> pair to guarantee the validness.  But
both id and address can be reused, there is theoretical possibility when
module inserted right after another module removed, kmalloc returns an
address same as the address kfree by previous module and IDR key reuses
the key recently removed.

Add a sequence number to codetag_module and code_iterator, the sequence
number is strickly incremented whenever a module is loaded.  An iterator
is valid if and only if its sequence number match codetag_module's.

Link: https://lkml.kernel.org/r/20250609064200.112639-1-00107082@163.com
Signed-off-by: David Wang <00107082@163.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/codetag.h |    1 +
 lib/codetag.c           |   17 ++++++++++++++---
 2 files changed, 15 insertions(+), 3 deletions(-)

--- a/include/linux/codetag.h~alloc_tag-add-sequence-number-for-module-and-iterator
+++ a/include/linux/codetag.h
@@ -54,6 +54,7 @@ struct codetag_iterator {
 	struct codetag_module *cmod;
 	unsigned long mod_id;
 	struct codetag *ct;
+	unsigned long mod_seq;
 };
 
 #ifdef MODULE
--- a/lib/codetag.c~alloc_tag-add-sequence-number-for-module-and-iterator
+++ a/lib/codetag.c
@@ -11,8 +11,14 @@ struct codetag_type {
 	struct list_head link;
 	unsigned int count;
 	struct idr mod_idr;
-	struct rw_semaphore mod_lock; /* protects mod_idr */
+	/*
+	 * protects mod_idr, next_mod_seq,
+	 * iter->mod_seq and cmod->mod_seq
+	 */
+	struct rw_semaphore mod_lock;
 	struct codetag_type_desc desc;
+	/* generates unique sequence number for module load */
+	unsigned long next_mod_seq;
 };
 
 struct codetag_range {
@@ -23,6 +29,7 @@ struct codetag_range {
 struct codetag_module {
 	struct module *mod;
 	struct codetag_range range;
+	unsigned long mod_seq;
 };
 
 static DEFINE_MUTEX(codetag_lock);
@@ -48,6 +55,7 @@ struct codetag_iterator codetag_get_ct_i
 		.cmod = NULL,
 		.mod_id = 0,
 		.ct = NULL,
+		.mod_seq = 0,
 	};
 
 	return iter;
@@ -91,11 +99,13 @@ struct codetag *codetag_next_ct(struct c
 		if (!cmod)
 			break;
 
-		if (cmod != iter->cmod) {
+		if (!iter->cmod || iter->mod_seq != cmod->mod_seq) {
 			iter->cmod = cmod;
+			iter->mod_seq = cmod->mod_seq;
 			ct = get_first_module_ct(cmod);
-		} else
+		} else {
 			ct = get_next_module_ct(iter);
+		}
 
 		if (ct)
 			break;
@@ -191,6 +201,7 @@ static int codetag_module_init(struct co
 	cmod->range = range;
 
 	down_write(&cttype->mod_lock);
+	cmod->mod_seq = ++cttype->next_mod_seq;
 	mod_id = idr_alloc(&cttype->mod_idr, cmod, 0, 0, GFP_KERNEL);
 	if (mod_id >= 0) {
 		if (cttype->desc.module_load) {
_

Patches currently in -mm which might be from 00107082@163.com are

alloc_tag-add-sequence-number-for-module-and-iterator.patch
alloc_tag-keep-codetag-iterator-active-between-read.patch