* [PATCH 4.19 73/80] exit: Allow oops_limit to be disabled
[not found] <20230203101015.263854890@linuxfoundation.org>
@ 2023-02-03 10:13 ` Greg Kroah-Hartman
2023-02-03 10:13 ` [PATCH 4.19 75/80] panic: Introduce warn_limit Greg Kroah-Hartman
1 sibling, 0 replies; 2+ messages in thread
From: Greg Kroah-Hartman @ 2023-02-03 10:13 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Jann Horn, Jonathan Corbet,
Andrew Morton, Baolin Wang, Jason A. Donenfeld, Eric Biggers,
Huang Ying, Eric W. Biederman, Arnd Bergmann, linux-doc,
Kees Cook
From: Kees Cook <keescook@chromium.org>
commit de92f65719cd672f4b48397540b9f9eff67eca40 upstream.
In preparation for keeping oops_limit logic in sync with warn_limit,
have oops_limit == 0 disable checking the Oops counter.
Cc: Jann Horn <jannh@google.com>
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: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linux-doc@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
Documentation/sysctl/kernel.txt | 5 +++--
kernel/exit.c | 2 +-
2 files changed, 4 insertions(+), 3 deletions(-)
--- a/Documentation/sysctl/kernel.txt
+++ b/Documentation/sysctl/kernel.txt
@@ -559,8 +559,9 @@ scanned for a given scan.
oops_limit:
Number of kernel oopses after which the kernel should panic when
-``panic_on_oops`` is not set. Setting this to 0 or 1 has the same effect
-as setting ``panic_on_oops=1``.
+``panic_on_oops`` is not set. Setting this to 0 disables checking
+the count. Setting this to 1 has the same effect as setting
+``panic_on_oops=1``. The default value is 10000.
==============================================================
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -986,7 +986,7 @@ void __noreturn make_task_dead(int signr
* To make sure this can't happen, place an upper bound on how often the
* kernel may oops without panic().
*/
- if (atomic_inc_return(&oops_count) >= READ_ONCE(oops_limit))
+ if (atomic_inc_return(&oops_count) >= READ_ONCE(oops_limit) && oops_limit)
panic("Oopsed too often (kernel.oops_limit is %d)", oops_limit);
do_exit(signr);
^ permalink raw reply [flat|nested] 2+ messages in thread
* [PATCH 4.19 75/80] panic: Introduce warn_limit
[not found] <20230203101015.263854890@linuxfoundation.org>
2023-02-03 10:13 ` [PATCH 4.19 73/80] exit: Allow oops_limit to be disabled Greg Kroah-Hartman
@ 2023-02-03 10:13 ` Greg Kroah-Hartman
1 sibling, 0 replies; 2+ messages in thread
From: Greg Kroah-Hartman @ 2023-02-03 10:13 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Jonathan Corbet, Andrew Morton,
Baolin Wang, Jason A. Donenfeld, Eric Biggers, Huang Ying,
Petr Mladek, tangmeng, Guilherme G. Piccoli, Tiezhu Yang,
Sebastian Andrzej Siewior, linux-doc, Luis Chamberlain,
Kees Cook
From: Kees Cook <keescook@chromium.org>
commit 9fc9e278a5c0b708eeffaf47d6eb0c82aa74ed78 upstream.
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
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20221117234328.594699-5-keescook@chromium.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
Documentation/sysctl/kernel.txt | 10 ++++++++++
kernel/panic.c | 27 +++++++++++++++++++++++++++
2 files changed, 37 insertions(+)
--- a/Documentation/sysctl/kernel.txt
+++ b/Documentation/sysctl/kernel.txt
@@ -97,6 +97,7 @@ show up in /proc/sys/kernel:
- threads-max
- unprivileged_bpf_disabled
- unknown_nmi_panic
+- warn_limit
- watchdog
- watchdog_thresh
- version
@@ -1114,6 +1115,15 @@ example. If a system hangs up, try pres
==============================================================
+warn_limit:
+
+Number of kernel warnings after which the kernel should panic when
+``panic_on_warn`` is not set. Setting this to 0 disables checking
+the warning count. Setting this to 1 has the same effect as setting
+``panic_on_warn=1``. The default value is 0.
+
+==============================================================
+
watchdog:
This parameter can be used to disable or enable the soft lockup detector
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -42,6 +42,7 @@ static int pause_on_oops_flag;
static DEFINE_SPINLOCK(pause_on_oops_lock);
bool crash_kexec_post_notifiers;
int panic_on_warn __read_mostly;
+static unsigned int warn_limit __read_mostly;
int panic_timeout = CONFIG_PANIC_TIMEOUT;
EXPORT_SYMBOL_GPL(panic_timeout);
@@ -50,6 +51,26 @@ ATOMIC_NOTIFIER_HEAD(panic_notifier_list
EXPORT_SYMBOL(panic_notifier_list);
+#ifdef CONFIG_SYSCTL
+static struct ctl_table kern_panic_table[] = {
+ {
+ .procname = "warn_limit",
+ .data = &warn_limit,
+ .maxlen = sizeof(warn_limit),
+ .mode = 0644,
+ .proc_handler = proc_douintvec,
+ },
+ { }
+};
+
+static __init int kernel_panic_sysctls_init(void)
+{
+ register_sysctl_init("kernel", kern_panic_table);
+ return 0;
+}
+late_initcall(kernel_panic_sysctls_init);
+#endif
+
static long no_blink(int state)
{
return 0;
@@ -127,8 +148,14 @@ EXPORT_SYMBOL(nmi_panic);
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);
+
+ if (atomic_inc_return(&warn_count) >= READ_ONCE(warn_limit) && warn_limit)
+ panic("%s: system warned too often (kernel.warn_limit is %d)",
+ origin, warn_limit);
}
/**
^ permalink raw reply [flat|nested] 2+ messages in thread
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