diff options
| -rw-r--r-- | Documentation/clearing-warn-once.txt | 7 | ||||
| -rw-r--r-- | include/asm-generic/bug.h | 6 | ||||
| -rw-r--r-- | include/asm-generic/sections.h | 1 | ||||
| -rw-r--r-- | include/asm-generic/vmlinux.lds.h | 3 | ||||
| -rw-r--r-- | kernel/panic.c | 28 |
5 files changed, 42 insertions, 3 deletions
diff --git a/Documentation/clearing-warn-once.txt b/Documentation/clearing-warn-once.txt new file mode 100644 index 000000000000..5b1f5d547be1 --- /dev/null +++ b/Documentation/clearing-warn-once.txt @@ -0,0 +1,7 @@ + +WARN_ONCE / WARN_ON_ONCE only print a warning once. + +echo 1 > /sys/kernel/debug/clear_warn_once + +clears the state and allows the warnings to print once again. +This can be useful after test suite runs to reproduce problems. diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h index af2cc94a61bf..7844b0df88cd 100644 --- a/include/asm-generic/bug.h +++ b/include/asm-generic/bug.h @@ -130,7 +130,7 @@ void __warn(const char *file, int line, void *caller, unsigned taint, #ifndef WARN_ON_ONCE #define WARN_ON_ONCE(condition) ({ \ - static bool __section(.data.unlikely) __warned; \ + static bool __section(.data.once) __warned; \ int __ret_warn_once = !!(condition); \ \ if (unlikely(__ret_warn_once && !__warned)) { \ @@ -142,7 +142,7 @@ void __warn(const char *file, int line, void *caller, unsigned taint, #endif #define WARN_ONCE(condition, format...) ({ \ - static bool __section(.data.unlikely) __warned; \ + static bool __section(.data.once) __warned; \ int __ret_warn_once = !!(condition); \ \ if (unlikely(__ret_warn_once && !__warned)) { \ @@ -153,7 +153,7 @@ void __warn(const char *file, int line, void *caller, unsigned taint, }) #define WARN_TAINT_ONCE(condition, taint, format...) ({ \ - static bool __section(.data.unlikely) __warned; \ + static bool __section(.data.once) __warned; \ int __ret_warn_once = !!(condition); \ \ if (unlikely(__ret_warn_once && !__warned)) { \ diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h index 6d9576931084..03cc5f9bba71 100644 --- a/include/asm-generic/sections.h +++ b/include/asm-generic/sections.h @@ -44,6 +44,7 @@ extern char __entry_text_start[], __entry_text_end[]; extern char __start_rodata[], __end_rodata[]; extern char __irqentry_text_start[], __irqentry_text_end[]; extern char __softirqentry_text_start[], __softirqentry_text_end[]; +extern char __start_once[], __end_once[]; /* Start and end of .ctors section - used for constructor calls. */ extern char __ctors_start[], __ctors_end[]; diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index bdcd1caae092..ee8b707d9fa9 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -223,6 +223,9 @@ MEM_KEEP(init.data) \ MEM_KEEP(exit.data) \ *(.data.unlikely) \ + VMLINUX_SYMBOL(__start_once) = .; \ + *(.data.once) \ + VMLINUX_SYMBOL(__end_once) = .; \ STRUCT_ALIGN(); \ *(__tracepoints) \ /* implement dynamic printk debug */ \ diff --git a/kernel/panic.c b/kernel/panic.c index bdd18afa19a4..672a91dc20fe 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -27,6 +27,8 @@ #include <linux/console.h> #include <linux/bug.h> #include <linux/ratelimit.h> +#include <linux/debugfs.h> +#include <asm/sections.h> #define PANIC_TIMER_STEP 100 #define PANIC_BLINK_SPD 18 @@ -587,6 +589,32 @@ void warn_slowpath_null(const char *file, int line) EXPORT_SYMBOL(warn_slowpath_null); #endif +#ifdef CONFIG_BUG + +/* Support resetting WARN*_ONCE state */ + +static int clear_warn_once_set(void *data, u64 val) +{ + memset(__start_once, 0, __end_once - __start_once); + return 0; +} + +DEFINE_SIMPLE_ATTRIBUTE(clear_warn_once_fops, + NULL, + clear_warn_once_set, + "%lld\n"); + +static __init int register_warn_debugfs(void) +{ + /* Don't care about failure */ + debugfs_create_file("clear_warn_once", 0644, NULL, + NULL, &clear_warn_once_fops); + return 0; +} + +device_initcall(register_warn_debugfs); +#endif + #ifdef CONFIG_CC_STACKPROTECTOR /* |