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Message-Id: <20220614043830.99607-2-pizhenwei@bytedance.com>
Date: Tue, 14 Jun 2022 12:38:29 +0800
From: zhenwei pi <pizhenwei@...edance.com>
To: akpm@...ux-foundation.org, naoya.horiguchi@....com
Cc: linux-mm@...ck.org, linux-kernel@...r.kernel.org, david@...hat.com,
linmiaohe@...wei.com, zhenwei pi <pizhenwei@...edance.com>
Subject: [PATCH v4 1/2] mm/memory-failure: introduce "hwpoisoned-pages" entry
Add a new debug entry to show the number of hwpoisoned pages. And
use module_get/module_put to manager this kernel module, don't allow
to remove this module unless hwpoisoned-pages is zero.
Signed-off-by: zhenwei pi <pizhenwei@...edance.com>
---
Documentation/vm/hwpoison.rst | 4 ++++
mm/hwpoison-inject.c | 19 ++++++++++++++++++-
2 files changed, 22 insertions(+), 1 deletion(-)
diff --git a/Documentation/vm/hwpoison.rst b/Documentation/vm/hwpoison.rst
index c742de1769d1..c832a8b192d4 100644
--- a/Documentation/vm/hwpoison.rst
+++ b/Documentation/vm/hwpoison.rst
@@ -155,6 +155,10 @@ Testing
flag bits are defined in include/linux/kernel-page-flags.h and
documented in Documentation/admin-guide/mm/pagemap.rst
+ hwpoisoned-pages
+ The number of hwpoisoned pages. The hwpoison kernel module can not be
+ removed unless this count is zero.
+
* Architecture specific MCE injector
x86 has mce-inject, mce-test
diff --git a/mm/hwpoison-inject.c b/mm/hwpoison-inject.c
index 5c0cddd81505..9e522ecedeef 100644
--- a/mm/hwpoison-inject.c
+++ b/mm/hwpoison-inject.c
@@ -10,6 +10,7 @@
#include "internal.h"
static struct dentry *hwpoison_dir;
+static atomic_t hwpoisoned_pages;
static int hwpoison_inject(void *data, u64 val)
{
@@ -49,15 +50,28 @@ static int hwpoison_inject(void *data, u64 val)
inject:
pr_info("Injecting memory failure at pfn %#lx\n", pfn);
err = memory_failure(pfn, 0);
+ if (!err) {
+ WARN_ON(!try_module_get(THIS_MODULE));
+ atomic_inc(&hwpoisoned_pages);
+ }
+
return (err == -EOPNOTSUPP) ? 0 : err;
}
static int hwpoison_unpoison(void *data, u64 val)
{
+ int ret;
+
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
- return unpoison_memory(val);
+ ret = unpoison_memory(val);
+ if (!ret) {
+ atomic_dec(&hwpoisoned_pages);
+ module_put(THIS_MODULE);
+ }
+
+ return ret;
}
DEFINE_DEBUGFS_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n");
@@ -99,6 +113,9 @@ static int pfn_inject_init(void)
debugfs_create_u64("corrupt-filter-flags-value", 0600, hwpoison_dir,
&hwpoison_filter_flags_value);
+ debugfs_create_atomic_t("hwpoisoned-pages", 0400, hwpoison_dir,
+ &hwpoisoned_pages);
+
#ifdef CONFIG_MEMCG
debugfs_create_u64("corrupt-filter-memcg", 0600, hwpoison_dir,
&hwpoison_filter_memcg);
--
2.20.1
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