linux-kernel - [PATCH v4] debugobjects: install CPU hotplug callback

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <20200923032905.20738-1-qiang.zhang@windriver.com>
Date:   Wed, 23 Sep 2020 11:29:05 +0800
From:   <qiang.zhang@...driver.com>
To:     <tglx@...utronix.de>, <miaoqinglang@...wei.com>,
        <elver@...gle.com>, <longman@...hat.com>,
        <akpm@...ux-foundation.org>, <cai@....us>
CC:     <linux-kernel@...r.kernel.org>
Subject: [PATCH v4] debugobjects: install CPU hotplug callback

From: Zqiang <qiang.zhang@...driver.com>

Due to CPU hotplug, it may never be online after it's offline,
some objects in percpu pool is never free. in order to avoid
this happening, install CPU hotplug callback, call this callback
func to free objects in percpu pool when CPU going offline.

Signed-off-by: Zqiang <qiang.zhang@...driver.com>
Acked-by: Waiman Long <longman@...hat.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: "Joel Fernandes (Google)" <joel@...lfernandes.org>
Cc: Qian Cai <cai@....us>
---
 v1->v2:
 Modify submission information.

 v2->v3:
 In CPU hotplug callback func, add clear percpu pool "obj_free" operation.
 capitalize 'CPU', and use shorter preprocessor sequence.

 v3->v4:
 Add Cc and Acked-by tags

 include/linux/cpuhotplug.h |  1 +
 lib/debugobjects.c         | 24 ++++++++++++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 3215023d4852..0c39d57e5342 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -36,6 +36,7 @@ enum cpuhp_state {
 	CPUHP_X86_MCE_DEAD,
 	CPUHP_VIRT_NET_DEAD,
 	CPUHP_SLUB_DEAD,
+	CPUHP_DEBUG_OBJ_DEAD,
 	CPUHP_MM_WRITEBACK_DEAD,
 	CPUHP_MM_VMSTAT_DEAD,
 	CPUHP_SOFTIRQ_DEAD,
diff --git a/lib/debugobjects.c b/lib/debugobjects.c
index fe4557955d97..bb69a02c3e7b 100644
--- a/lib/debugobjects.c
+++ b/lib/debugobjects.c
@@ -19,6 +19,7 @@
 #include <linux/slab.h>
 #include <linux/hash.h>
 #include <linux/kmemleak.h>
+#include <linux/cpu.h>
 
 #define ODEBUG_HASH_BITS	14
 #define ODEBUG_HASH_SIZE	(1 << ODEBUG_HASH_BITS)
@@ -433,6 +434,24 @@ static void free_object(struct debug_obj *obj)
 	}
 }
 
+#ifdef CONFIG_HOTPLUG_CPU
+static int object_cpu_offline(unsigned int cpu)
+{
+	struct debug_percpu_free *percpu_pool;
+	struct hlist_node *tmp;
+	struct debug_obj *obj;
+
+	percpu_pool = per_cpu_ptr(&percpu_obj_pool, cpu);
+	hlist_for_each_entry_safe(obj, tmp, &percpu_pool->free_objs, node) {
+		hlist_del(&obj->node);
+		kmem_cache_free(obj_cache, obj);
+	}
+	percpu_pool->obj_free = 0;
+
+	return 0;
+}
+#endif
+
 /*
  * We run out of memory. That means we probably have tons of objects
  * allocated.
@@ -1367,6 +1386,11 @@ void __init debug_objects_mem_init(void)
 	} else
 		debug_objects_selftest();
 
+#ifdef CONFIG_HOTPLUG_CPU
+	cpuhp_setup_state_nocalls(CPUHP_DEBUG_OBJ_DEAD, "object:offline", NULL,
+					object_cpu_offline);
+#endif
+
 	/*
 	 * Increase the thresholds for allocating and freeing objects
 	 * according to the number of possible CPUs available in the system.
-- 
2.17.1