From: Kees Cook <keescook@xxxxxxxxxxxx> commit 9db89b41117024f80b38b15954017fb293133364 upstream. Since Oops count is now tracked and is a fairly interesting signal, add the entry /sys/kernel/oops_count to expose it to userspace. Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> Cc: Jann Horn <jannh@xxxxxxxxxx> Cc: Arnd Bergmann <arnd@xxxxxxxx> Reviewed-by: Luis Chamberlain <mcgrof@xxxxxxxxxx> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> Link: https://lore.kernel.org/r/20221117234328.594699-3-keescook@xxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- Documentation/ABI/testing/sysfs-kernel-oops_count | 6 ++++++ MAINTAINERS | 1 + kernel/exit.c | 22 ++++++++++++++++++++-- 3 files changed, 27 insertions(+), 2 deletions(-) create mode 100644 Documentation/ABI/testing/sysfs-kernel-oops_count --- /dev/null +++ b/Documentation/ABI/testing/sysfs-kernel-oops_count @@ -0,0 +1,6 @@ +What: /sys/kernel/oops_count +Date: November 2022 +KernelVersion: 6.2.0 +Contact: Linux Kernel Hardening List <linux-hardening@xxxxxxxxxxxxxxx> +Description: + Shows how many times the system has Oopsed since last boot. --- a/MAINTAINERS +++ b/MAINTAINERS @@ -11112,6 +11112,7 @@ M: Kees Cook <keescook@xxxxxxxxxxxx> L: linux-hardening@xxxxxxxxxxxxxxx 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: include/linux/overflow.h F: include/linux/randomize_kstack.h F: mm/usercopy.c --- a/kernel/exit.c +++ b/kernel/exit.c @@ -67,6 +67,7 @@ #include <linux/io_uring.h> #include <linux/kprobes.h> #include <linux/rethook.h> +#include <linux/sysfs.h> #include <linux/uaccess.h> #include <asm/unistd.h> @@ -99,6 +100,25 @@ static __init int kernel_exit_sysctls_in late_initcall(kernel_exit_sysctls_init); #endif +static atomic_t oops_count = ATOMIC_INIT(0); + +#ifdef CONFIG_SYSFS +static ssize_t oops_count_show(struct kobject *kobj, struct kobj_attribute *attr, + char *page) +{ + return sysfs_emit(page, "%d\n", atomic_read(&oops_count)); +} + +static struct kobj_attribute oops_count_attr = __ATTR_RO(oops_count); + +static __init int kernel_exit_sysfs_init(void) +{ + sysfs_add_file_to_group(kernel_kobj, &oops_count_attr.attr, NULL); + return 0; +} +late_initcall(kernel_exit_sysfs_init); +#endif + static void __unhash_process(struct task_struct *p, bool group_dead) { nr_threads--; @@ -901,8 +921,6 @@ void __noreturn do_exit(long code) void __noreturn make_task_dead(int signr) { - static atomic_t oops_count = ATOMIC_INIT(0); - /* * Take the task off the cpu after something catastrophic has * happened.
