Commit 8b05aa26 authored by Kees Cook's avatar Kees Cook
Browse files

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@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: tangmeng <tangmeng@uniontech.com>
Cc: "Guilherme G. Piccoli" <gpiccoli@igalia.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Tiezhu Yang <yangtiezhu@loongson.cn>
Reviewed-by: default avatarLuis Chamberlain <mcgrof@kernel.org>
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20221117234328.594699-6-keescook@chromium.org
parent 9fc9e278

Documentation/ABI/testing/sysfs-kernel-warn_count

0 → 100644
+6 −0
Original line number Diff line number Diff line 
What:		/sys/kernel/oops_count

Date:		November 2022

KernelVersion:	6.2.0

Contact:	Linux Kernel Hardening List <linux-hardening@vger.kernel.org>

Description:

		Shows how many times the system has Warned since last boot.

MAINTAINERS

+1 −0
Original line number Diff line number Diff line
@@ -11107,6 +11107,7 @@ L: linux-hardening@vger.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

kernel/panic.c

+20 −2
Original line number Diff line number Diff line
@@ -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);