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panic: Introduce warn_limit

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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>
This commit is contained in:
Kees Cook 2023-02-02 16:27:14 -08:00 committed by Greg Kroah-Hartman
parent dcdce95219
commit a40af7cd60
2 changed files with 37 additions and 0 deletions
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10
Documentation/sysctl/kernel.txt
View File

@ -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 pressing the NMI switch.
==============================================================
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

27
kernel/panic.c
View File

@ -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);
}
/**