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Message-Id: <20221117234328.594699-6-keescook@chromium.org>
Date: Thu, 17 Nov 2022 15:43:26 -0800
From: Kees Cook <keescook@...omium.org>
To: Jann Horn <jannh@...gle.com>
Cc: Kees Cook <keescook@...omium.org>, Petr Mladek <pmladek@...e.com>,
Andrew Morton <akpm@...ux-foundation.org>,
tangmeng <tangmeng@...ontech.com>,
"Guilherme G. Piccoli" <gpiccoli@...lia.com>,
Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
Tiezhu Yang <yangtiezhu@...ngson.cn>,
Luis Chamberlain <mcgrof@...nel.org>,
Seth Jenkins <sethjenkins@...gle.com>,
Greg KH <gregkh@...uxfoundation.org>,
Linus Torvalds <torvalds@...uxfoundation.org>,
Andy Lutomirski <luto@...nel.org>,
"Eric W. Biederman" <ebiederm@...ssion.com>,
Arnd Bergmann <arnd@...db.de>,
Dmitry Vyukov <dvyukov@...gle.com>,
Peter Zijlstra <peterz@...radead.org>,
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>,
Daniel Bristot de Oliveira <bristot@...hat.com>,
Valentin Schneider <vschneid@...hat.com>,
Andrey Ryabinin <ryabinin.a.a@...il.com>,
Alexander Potapenko <glider@...gle.com>,
Andrey Konovalov <andreyknvl@...il.com>,
Vincenzo Frascino <vincenzo.frascino@....com>,
David Gow <davidgow@...gle.com>,
"Paul E. McKenney" <paulmck@...nel.org>,
Jonathan Corbet <corbet@....net>,
Baolin Wang <baolin.wang@...ux.alibaba.com>,
"Jason A. Donenfeld" <Jason@...c4.com>,
Eric Biggers <ebiggers@...gle.com>,
Huang Ying <ying.huang@...el.com>,
Anton Vorontsov <anton@...msg.org>,
Mauro Carvalho Chehab <mchehab+huawei@...nel.org>,
Laurent Dufour <ldufour@...ux.ibm.com>,
Rob Herring <robh@...nel.org>, linux-kernel@...r.kernel.org,
kasan-dev@...glegroups.com, linux-mm@...ck.org,
linux-doc@...r.kernel.org, linux-hardening@...r.kernel.org
Subject: [PATCH v3 6/6] panic: Expose "warn_count" to sysfs
Since Warn count is now tracked and is a fairly interesting signal, add
the entry /sys/kernel/warn_count to expose it to userspace.
Cc: Petr Mladek <pmladek@...e.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: tangmeng <tangmeng@...ontech.com>
Cc: "Guilherme G. Piccoli" <gpiccoli@...lia.com>
Cc: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Cc: Tiezhu Yang <yangtiezhu@...ngson.cn>
Reviewed-by: Luis Chamberlain <mcgrof@...nel.org>
Signed-off-by: Kees Cook <keescook@...omium.org>
---
.../ABI/testing/sysfs-kernel-warn_count | 6 +++++
MAINTAINERS | 1 +
kernel/panic.c | 22 +++++++++++++++++--
3 files changed, 27 insertions(+), 2 deletions(-)
create mode 100644 Documentation/ABI/testing/sysfs-kernel-warn_count
diff --git a/Documentation/ABI/testing/sysfs-kernel-warn_count b/Documentation/ABI/testing/sysfs-kernel-warn_count
new file mode 100644
index 000000000000..08f083d2fd51
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-kernel-warn_count
@@ -0,0 +1,6 @@
+What: /sys/kernel/oops_count
+Date: November 2022
+KernelVersion: 6.2.0
+Contact: Linux Kernel Hardening List <linux-hardening@...r.kernel.org>
+Description:
+ Shows how many times the system has Warned since last boot.
diff --git a/MAINTAINERS b/MAINTAINERS
index 0a1e95a58e54..282cd8a513fd 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11107,6 +11107,7 @@ L: linux-hardening@...r.kernel.org
S: Supported
T: git git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git for-next/hardening
F: Documentation/ABI/testing/sysfs-kernel-oops_count
+F: Documentation/ABI/testing/sysfs-kernel-warn_count
F: include/linux/overflow.h
F: include/linux/randomize_kstack.h
F: mm/usercopy.c
diff --git a/kernel/panic.c b/kernel/panic.c
index e5aab27496d7..d718531d8bf4 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -32,6 +32,7 @@
#include <linux/bug.h>
#include <linux/ratelimit.h>
#include <linux/debugfs.h>
+#include <linux/sysfs.h>
#include <trace/events/error_report.h>
#include <asm/sections.h>
@@ -107,6 +108,25 @@ static __init int kernel_panic_sysctls_init(void)
late_initcall(kernel_panic_sysctls_init);
#endif
+static atomic_t warn_count = ATOMIC_INIT(0);
+
+#ifdef CONFIG_SYSFS
+static ssize_t warn_count_show(struct kobject *kobj, struct kobj_attribute *attr,
+ char *page)
+{
+ return sysfs_emit(page, "%d\n", atomic_read(&warn_count));
+}
+
+static struct kobj_attribute warn_count_attr = __ATTR_RO(warn_count);
+
+static __init int kernel_panic_sysfs_init(void)
+{
+ sysfs_add_file_to_group(kernel_kobj, &warn_count_attr.attr, NULL);
+ return 0;
+}
+late_initcall(kernel_panic_sysfs_init);
+#endif
+
static long no_blink(int state)
{
return 0;
@@ -211,8 +231,6 @@ static void panic_print_sys_info(bool console_flush)
void check_panic_on_warn(const char *origin)
{
- static atomic_t warn_count = ATOMIC_INIT(0);
-
if (panic_on_warn)
panic("%s: panic_on_warn set ...\n", origin);
--
2.34.1
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