Merge tag 'hardening-v6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees...

[platform/kernel/linux-starfive.git] / kernel / panic.c

diff --git a/kernel/panic.c b/kernel/panic.c
index 75fe389..326d915 100644 (file)
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -33,6 +33,7 @@
 #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>
 
@@ -59,6 +60,7 @@ 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;
 
 int panic_timeout = CONFIG_PANIC_TIMEOUT;
 EXPORT_SYMBOL_GPL(panic_timeout);
@@ -76,8 +78,9 @@ ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
 
 EXPORT_SYMBOL(panic_notifier_list);
 
-#if defined(CONFIG_SMP) && defined(CONFIG_SYSCTL)
+#ifdef CONFIG_SYSCTL
 static struct ctl_table kern_panic_table[] = {
+#ifdef CONFIG_SMP
        {
                .procname       = "oops_all_cpu_backtrace",
                .data           = &sysctl_oops_all_cpu_backtrace,
@@ -87,6 +90,14 @@ static struct ctl_table kern_panic_table[] = {
                .extra1         = SYSCTL_ZERO,
                .extra2         = SYSCTL_ONE,
        },
+#endif
+       {
+               .procname       = "warn_limit",
+               .data           = &warn_limit,
+               .maxlen         = sizeof(warn_limit),
+               .mode           = 0644,
+               .proc_handler   = proc_douintvec,
+       },
        { }
 };
 
@@ -98,6 +109,25 @@ 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;
@@ -200,6 +230,16 @@ static void panic_print_sys_info(bool console_flush)
                ftrace_dump(DUMP_ALL);
 }
 
+void check_panic_on_warn(const char *origin)
+{
+       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);
+}
+
 /**
  *     panic - halt the system
  *     @fmt: The text string to print
@@ -618,8 +658,7 @@ void __warn(const char *file, int line, void *caller, unsigned taint,
        if (regs)
                show_regs(regs);
 
-       if (panic_on_warn)
-               panic("panic_on_warn set ...\n");
+       check_panic_on_warn("kernel");
 
        if (!regs)
                dump_stack();