| 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
| ||
|
Message-ID: <20250930024402.1043776-7-wangjinchao600@gmail.com>
Date: Tue, 30 Sep 2025 10:43:27 +0800
From: Jinchao Wang <wangjinchao600@...il.com>
To: Andrew Morton <akpm@...ux-foundation.org>,
Masami Hiramatsu <mhiramat@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
Mike Rapoport <rppt@...nel.org>,
Alexander Potapenko <glider@...gle.com>,
Randy Dunlap <rdunlap@...radead.org>,
Marco Elver <elver@...gle.com>,
Jonathan Corbet <corbet@....net>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
Borislav Petkov <bp@...en8.de>,
Dave Hansen <dave.hansen@...ux.intel.com>,
x86@...nel.org,
"H. Peter Anvin" <hpa@...or.com>,
Juri Lelli <juri.lelli@...hat.com>,
Vincent Guittot <vincent.guittot@...aro.org>,
Dietmar Eggemann <dietmar.eggemann@....com>,
Steven Rostedt <rostedt@...dmis.org>,
Ben Segall <bsegall@...gle.com>,
Mel Gorman <mgorman@...e.de>,
Valentin Schneider <vschneid@...hat.com>,
Arnaldo Carvalho de Melo <acme@...nel.org>,
Namhyung Kim <namhyung@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Jiri Olsa <jolsa@...nel.org>,
Ian Rogers <irogers@...gle.com>,
Adrian Hunter <adrian.hunter@...el.com>,
"Liang, Kan" <kan.liang@...ux.intel.com>,
David Hildenbrand <david@...hat.com>,
Lorenzo Stoakes <lorenzo.stoakes@...cle.com>,
"Liam R. Howlett" <Liam.Howlett@...cle.com>,
Vlastimil Babka <vbabka@...e.cz>,
Suren Baghdasaryan <surenb@...gle.com>,
Michal Hocko <mhocko@...e.com>,
Nathan Chancellor <nathan@...nel.org>,
Nick Desaulniers <nick.desaulniers+lkml@...il.com>,
Bill Wendling <morbo@...gle.com>,
Justin Stitt <justinstitt@...gle.com>,
Kees Cook <kees@...nel.org>,
Alice Ryhl <aliceryhl@...gle.com>,
Sami Tolvanen <samitolvanen@...gle.com>,
Miguel Ojeda <ojeda@...nel.org>,
Masahiro Yamada <masahiroy@...nel.org>,
Rong Xu <xur@...gle.com>,
Naveen N Rao <naveen@...nel.org>,
David Kaplan <david.kaplan@....com>,
Andrii Nakryiko <andrii@...nel.org>,
Jinjie Ruan <ruanjinjie@...wei.com>,
Nam Cao <namcao@...utronix.de>,
workflows@...r.kernel.org,
linux-doc@...r.kernel.org,
linux-kernel@...r.kernel.org,
linux-perf-users@...r.kernel.org,
linux-mm@...ck.org,
llvm@...ts.linux.dev,
Andrey Ryabinin <ryabinin.a.a@...il.com>,
Andrey Konovalov <andreyknvl@...il.com>,
Dmitry Vyukov <dvyukov@...gle.com>,
Vincenzo Frascino <vincenzo.frascino@....com>,
kasan-dev@...glegroups.com,
"David S. Miller" <davem@...emloft.net>,
Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
linux-trace-kernel@...r.kernel.org
Cc: Jinchao Wang <wangjinchao600@...il.com>
Subject: [PATCH v6 06/23] mm/ksw: add singleton debugfs interface
Provide the debugfs config file to read or update the configuration.
Only a single process can open this file at a time, enforced using atomic
config_file_busy, to prevent concurrent access.
ksw_get_config() exposes the configuration pointer as const.
Signed-off-by: Jinchao Wang <wangjinchao600@...il.com>
---
mm/kstackwatch/kernel.c | 104 +++++++++++++++++++++++++++++++++--
mm/kstackwatch/kstackwatch.h | 3 +
2 files changed, 103 insertions(+), 4 deletions(-)
diff --git a/mm/kstackwatch/kernel.c b/mm/kstackwatch/kernel.c
index 3b7009033dd4..898ebb2966fe 100644
--- a/mm/kstackwatch/kernel.c
+++ b/mm/kstackwatch/kernel.c
@@ -1,13 +1,18 @@
// SPDX-License-Identifier: GPL-2.0
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/debugfs.h>
#include <linux/kstrtox.h>
#include <linux/module.h>
#include <linux/string.h>
+#include <linux/uaccess.h>
#include "kstackwatch.h"
+static atomic_t dbgfs_config_busy = ATOMIC_INIT(0);
static struct ksw_config *ksw_config;
+static struct dentry *dbgfs_config;
+static struct dentry *dbgfs_dir;
struct param_map {
const char *name; /* long name */
@@ -74,7 +79,7 @@ static int ksw_parse_param(struct ksw_config *config, const char *key,
* - sp_offset |so (u16) : offset from stack pointer at func_offset
* - watch_len |wl (u16) : watch length (1,2,4,8)
*/
-static int __maybe_unused ksw_parse_config(char *buf, struct ksw_config *config)
+static int ksw_parse_config(char *buf, struct ksw_config *config)
{
char *part, *key, *val;
int ret;
@@ -109,20 +114,111 @@ static int __maybe_unused ksw_parse_config(char *buf, struct ksw_config *config)
return 0;
}
+static ssize_t ksw_dbgfs_read(struct file *file, char __user *buf, size_t count,
+ loff_t *ppos)
+{
+ return simple_read_from_buffer(buf, count, ppos, ksw_config->user_input,
+ ksw_config->user_input ? strlen(ksw_config->user_input) : 0);
+}
+
+static ssize_t ksw_dbgfs_write(struct file *file, const char __user *buffer,
+ size_t count, loff_t *ppos)
+{
+ char input[MAX_CONFIG_STR_LEN];
+ int ret;
+
+ if (count == 0 || count >= sizeof(input))
+ return -EINVAL;
+
+ if (copy_from_user(input, buffer, count))
+ return -EFAULT;
+
+ input[count] = '\0';
+ strim(input);
+
+ if (!strlen(input)) {
+ pr_info("config cleared\n");
+ return count;
+ }
+
+ ret = ksw_parse_config(input, ksw_config);
+ if (ret) {
+ pr_err("Failed to parse config %d\n", ret);
+ return ret;
+ }
+
+ return count;
+}
+
+static int ksw_dbgfs_open(struct inode *inode, struct file *file)
+{
+ if (atomic_cmpxchg(&dbgfs_config_busy, 0, 1))
+ return -EBUSY;
+ return 0;
+}
+
+static int ksw_dbgfs_release(struct inode *inode, struct file *file)
+{
+ atomic_set(&dbgfs_config_busy, 0);
+ return 0;
+}
+
+static const struct file_operations kstackwatch_fops = {
+ .owner = THIS_MODULE,
+ .open = ksw_dbgfs_open,
+ .read = ksw_dbgfs_read,
+ .write = ksw_dbgfs_write,
+ .release = ksw_dbgfs_release,
+ .llseek = default_llseek,
+};
+
+const struct ksw_config *ksw_get_config(void)
+{
+ return ksw_config;
+}
+
static int __init kstackwatch_init(void)
{
+ int ret = 0;
+
ksw_config = kzalloc(sizeof(*ksw_config), GFP_KERNEL);
- if (!ksw_config)
- return -ENOMEM;
+ if (!ksw_config) {
+ ret = -ENOMEM;
+ goto err_alloc;
+ }
+
+ dbgfs_dir = debugfs_create_dir("kstackwatch", NULL);
+ if (!dbgfs_dir) {
+ ret = -ENOMEM;
+ goto err_dir;
+ }
+
+ dbgfs_config = debugfs_create_file("config", 0600, dbgfs_dir, NULL,
+ &kstackwatch_fops);
+ if (!dbgfs_config) {
+ ret = -ENOMEM;
+ goto err_file;
+ }
pr_info("module loaded\n");
return 0;
+
+err_file:
+ debugfs_remove_recursive(dbgfs_dir);
+ dbgfs_dir = NULL;
+err_dir:
+ kfree(ksw_config);
+ ksw_config = NULL;
+err_alloc:
+ return ret;
}
static void __exit kstackwatch_exit(void)
{
+ debugfs_remove_recursive(dbgfs_dir);
+ kfree(ksw_config->func_name);
+ kfree(ksw_config->user_input);
kfree(ksw_config);
-
pr_info("module unloaded\n");
}
diff --git a/mm/kstackwatch/kstackwatch.h b/mm/kstackwatch/kstackwatch.h
index a7bad207f863..983125d5cf18 100644
--- a/mm/kstackwatch/kstackwatch.h
+++ b/mm/kstackwatch/kstackwatch.h
@@ -29,4 +29,7 @@ struct ksw_config {
char *user_input;
};
+// singleton, only modified in kernel.c
+const struct ksw_config *ksw_get_config(void);
+
#endif /* _KSTACKWATCH_H */
--
2.43.0
Powered by blists - more mailing lists