From: Kees Cook keescook@chromium.org
commit 8b05aa26336113c4cea25f1c333ee8cd4fc212a6 upstream.
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: Luis Chamberlain mcgrof@kernel.org Signed-off-by: Kees Cook keescook@chromium.org Link: https://lore.kernel.org/r/20221117234328.594699-6-keescook@chromium.org Signed-off-by: Eric Biggers ebiggers@google.com --- .../ABI/testing/sysfs-kernel-warn_count | 6 +++++ kernel/panic.c | 22 +++++++++++++++++-- 2 files changed, 26 insertions(+), 2 deletions(-) create mode 100644 Documentation/ABI/testing/sysfs-kernel-warn_count
diff --git a/Documentation/ABI/testing/sysfs-kernel-warn_count b/Documentation/ABI/testing/sysfs-kernel-warn_count new file mode 100644 index 0000000000000..08f083d2fd51b --- /dev/null +++ b/Documentation/ABI/testing/sysfs-kernel-warn_count @@ -0,0 +1,6 @@ +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. diff --git a/kernel/panic.c b/kernel/panic.c index 604d7ad77042e..4aef355e9a5d1 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -32,6 +32,7 @@ #include <linux/bug.h> #include <linux/ratelimit.h> #include <linux/debugfs.h> +#include <linux/sysfs.h> #include <asm/sections.h>
#define PANIC_TIMER_STEP 100 @@ -105,6 +106,25 @@ 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; @@ -203,8 +223,6 @@ static void panic_print_sys_info(void)
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);