From: Kees Cook <keescook@chromium.org>
To: Jann Horn <jannh@google.com>
Cc: Kees Cook <keescook@chromium.org>,
Jonathan Corbet <corbet@lwn.net>,
Andrew Morton <akpm@linux-foundation.org>,
Baolin Wang <baolin.wang@linux.alibaba.com>,
"Jason A. Donenfeld" <Jason@zx2c4.com>,
Eric Biggers <ebiggers@google.com>,
Huang Ying <ying.huang@intel.com>, Petr Mladek <pmladek@suse.com>,
tangmeng <tangmeng@uniontech.com>,
"Guilherme G. Piccoli" <gpiccoli@igalia.com>,
Tiezhu Yang <yangtiezhu@loongson.cn>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
linux-doc@vger.kernel.org, Greg KH <gregkh@linuxfoundation.org>,
Linus Torvalds <torvalds@linuxfoundation.org>,
Seth Jenkins <sethjenkins@google.com>,
Andy Lutomirski <luto@kernel.org>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Arnd Bergmann <arnd@arndb.de>, Marco Elver <elver@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
Peter Zijlstra <peterz@infradead.org>,
Juri Lelli <juri.lelli@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Steven Rostedt <rostedt@goodmis.org>,
Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
Daniel Bristot de Oliveira <bristot@redhat.com>,
Valentin Schneider <vschneid@redhat.com>,
Andrey Ryabinin <ryabinin.a.a@gmail.com>,
Alexander Potapenko <glider@google.com>,
Andrey Konovalov <andreyknvl@gmail.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Luis Chamberlain <mcgrof@kernel.org>,
David Gow <davidgow@google.com>,
"Paul E. McKenney" <paulmck@kernel.org>,
Anton Vorontsov <anton@enomsg.org>,
Mauro Carvalho Chehab <mchehab+huawei@kernel.org>,
Laurent Dufour <ldufour@linux.ibm.com>,
Rob Herring <robh@kernel.org>,
linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com,
linux-mm@kvack.org, linux-hardening@vger.kernel.org
Subject: [PATCH v2 5/6] panic: Introduce warn_limit
Date: Wed, 9 Nov 2022 12:00:48 -0800 [thread overview]
Message-ID: <20221109200050.3400857-5-keescook@chromium.org> (raw)
In-Reply-To: <20221109194404.gonna.558-kees@kernel.org>
Like oops_limit, add warn_limit for limiting the number of warnings when
panic_on_warn is not set.
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: tangmeng <tangmeng@uniontech.com>
Cc: "Guilherme G. Piccoli" <gpiccoli@igalia.com>
Cc: Tiezhu Yang <yangtiezhu@loongson.cn>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: linux-doc@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
Documentation/admin-guide/sysctl/kernel.rst | 9 +++++++++
kernel/panic.c | 13 +++++++++++++
2 files changed, 22 insertions(+)
diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst
index 09f3fb2f8585..c385d5319cdf 100644
--- a/Documentation/admin-guide/sysctl/kernel.rst
+++ b/Documentation/admin-guide/sysctl/kernel.rst
@@ -1508,6 +1508,15 @@ entry will default to 2 instead of 0.
2 Unprivileged calls to ``bpf()`` are disabled
= =============================================================
+
+warn_limit
+==========
+
+Number of kernel warnings after which the kernel should panic when
+``panic_on_warn`` is not set. Setting this to 0 or 1 has the same effect
+as setting ``panic_on_warn=1``.
+
+
watchdog
========
diff --git a/kernel/panic.c b/kernel/panic.c
index 3afd234767bc..b235fa4a6fc8 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -58,6 +58,7 @@ bool crash_kexec_post_notifiers;
int panic_on_warn __read_mostly;
unsigned long panic_on_taint;
bool panic_on_taint_nousertaint = false;
+static unsigned int warn_limit __read_mostly = 10000;
int panic_timeout = CONFIG_PANIC_TIMEOUT;
EXPORT_SYMBOL_GPL(panic_timeout);
@@ -88,6 +89,13 @@ static struct ctl_table kern_panic_table[] = {
.extra2 = SYSCTL_ONE,
},
#endif
+ {
+ .procname = "warn_limit",
+ .data = &warn_limit,
+ .maxlen = sizeof(warn_limit),
+ .mode = 0644,
+ .proc_handler = proc_douintvec,
+ },
{ }
};
@@ -203,8 +211,13 @@ static void panic_print_sys_info(bool console_flush)
void check_panic_on_warn(const char *reason)
{
+ static atomic_t warn_count = ATOMIC_INIT(0);
+
if (panic_on_warn)
panic("%s: panic_on_warn set ...\n", reason);
+
+ if (atomic_inc_return(&warn_count) >= READ_ONCE(warn_limit))
+ panic("Warned too often (warn_limit is %d)", warn_limit);
}
/**
--
2.34.1
next prev parent reply other threads:[~2022-11-09 20:01 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-09 20:00 [PATCH next v2 0/6] exit: Put an upper limit on how often we can oops Kees Cook
2022-11-09 20:00 ` [PATCH v2 1/6] panic: Separate sysctl logic from CONFIG_SMP Kees Cook
2022-11-09 21:48 ` Bill Wendling
2022-11-10 0:02 ` Kees Cook
2022-11-09 20:00 ` [PATCH v2 2/6] exit: Put an upper limit on how often we can oops Kees Cook
2022-11-09 20:00 ` [PATCH v2 3/6] exit: Expose "oops_count" to sysfs Kees Cook
2022-11-09 20:00 ` [PATCH v2 4/6] panic: Consolidate open-coded panic_on_warn checks Kees Cook
2022-11-14 9:57 ` Marco Elver
2022-11-17 23:28 ` Kees Cook
2022-11-09 20:00 ` Kees Cook [this message]
2022-11-14 9:48 ` [PATCH v2 5/6] panic: Introduce warn_limit Marco Elver
2022-11-17 23:27 ` Kees Cook
2022-11-09 20:00 ` [PATCH v2 6/6] panic: Expose "warn_count" to sysfs Kees Cook
2022-11-09 21:16 ` [PATCH next v2 0/6] exit: Put an upper limit on how often we can oops Luis Chamberlain
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