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ad7d61f159
While for most kinds of issues we have counters, tracepoints, or metrics
with a stable interface which can reliably be used to indicate issues,
in order to react to production issues quickly we sometimes need to work
with the interface which most kernel developers naturally use when
developing: printk, and printk-esques like dev_printk.
dev_printk is by far the most likely custom subsystem printk to benefit
from the printk indexing infrastructure, since niche device issues
brought about by production changes, firmware upgrades, and the like are
one of the most common things that we need printk infrastructure's
assistance to monitor.
Often these errors were never expected to practically manifest in
reality, and exhibit in code without extensive (or any) metrics present.
As such, there are typically very few options for issue detection
available to those with large fleets at the time the incident happens,
and we thus benefit strongly from monitoring netconsole in these
instances.
As such, add the infrastructure for dev_printk to be indexed in the
printk index. Even on a minimal kernel config, the coverage of the base
kernel's printk index is significantly improved:
Before:
[root@ktst ~]# wc -l /sys/kernel/debug/printk/index/vmlinux
4497 /sys/kernel/debug/printk/index/vmlinux
After:
[root@ktst ~]# wc -l /sys/kernel/debug/printk/index/vmlinux
5573 /sys/kernel/debug/printk/index/vmlinux
In terms of implementation, in order to trivially disambiguate them,
dev_printk is now a macro which wraps _dev_printk.
Signed-off-by: Chris Down <chris@chrisdown.name>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Tested-by: Petr Mladek <pmladek@suse.com>
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/959c7aed1017cb2c9de922e0a820d397e29c6a5a.1623775748.git.chris@chrisdown.name
277 lines
9.1 KiB
C
277 lines
9.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* dev_printk.h - printk messages helpers for devices
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*
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* Copyright (c) 2001-2003 Patrick Mochel <mochel@osdl.org>
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* Copyright (c) 2004-2009 Greg Kroah-Hartman <gregkh@suse.de>
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* Copyright (c) 2008-2009 Novell Inc.
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*
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*/
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#ifndef _DEVICE_PRINTK_H_
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#define _DEVICE_PRINTK_H_
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#include <linux/compiler.h>
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#include <linux/types.h>
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#include <linux/ratelimit.h>
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#ifndef dev_fmt
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#define dev_fmt(fmt) fmt
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#endif
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struct device;
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#define PRINTK_INFO_SUBSYSTEM_LEN 16
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#define PRINTK_INFO_DEVICE_LEN 48
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struct dev_printk_info {
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char subsystem[PRINTK_INFO_SUBSYSTEM_LEN];
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char device[PRINTK_INFO_DEVICE_LEN];
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};
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#ifdef CONFIG_PRINTK
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__printf(3, 0) __cold
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int dev_vprintk_emit(int level, const struct device *dev,
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const char *fmt, va_list args);
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__printf(3, 4) __cold
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int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...);
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__printf(3, 4) __cold
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void _dev_printk(const char *level, const struct device *dev,
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const char *fmt, ...);
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__printf(2, 3) __cold
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void _dev_emerg(const struct device *dev, const char *fmt, ...);
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__printf(2, 3) __cold
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void _dev_alert(const struct device *dev, const char *fmt, ...);
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__printf(2, 3) __cold
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void _dev_crit(const struct device *dev, const char *fmt, ...);
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__printf(2, 3) __cold
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void _dev_err(const struct device *dev, const char *fmt, ...);
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__printf(2, 3) __cold
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void _dev_warn(const struct device *dev, const char *fmt, ...);
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__printf(2, 3) __cold
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void _dev_notice(const struct device *dev, const char *fmt, ...);
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__printf(2, 3) __cold
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void _dev_info(const struct device *dev, const char *fmt, ...);
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#else
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static inline __printf(3, 0)
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int dev_vprintk_emit(int level, const struct device *dev,
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const char *fmt, va_list args)
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{ return 0; }
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static inline __printf(3, 4)
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int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...)
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{ return 0; }
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static inline void __dev_printk(const char *level, const struct device *dev,
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struct va_format *vaf)
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{}
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static inline __printf(3, 4)
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void _dev_printk(const char *level, const struct device *dev,
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const char *fmt, ...)
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{}
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static inline __printf(2, 3)
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void _dev_emerg(const struct device *dev, const char *fmt, ...)
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{}
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static inline __printf(2, 3)
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void _dev_crit(const struct device *dev, const char *fmt, ...)
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{}
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static inline __printf(2, 3)
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void _dev_alert(const struct device *dev, const char *fmt, ...)
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{}
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static inline __printf(2, 3)
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void _dev_err(const struct device *dev, const char *fmt, ...)
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{}
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static inline __printf(2, 3)
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void _dev_warn(const struct device *dev, const char *fmt, ...)
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{}
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static inline __printf(2, 3)
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void _dev_notice(const struct device *dev, const char *fmt, ...)
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{}
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static inline __printf(2, 3)
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void _dev_info(const struct device *dev, const char *fmt, ...)
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{}
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#endif
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/*
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* Need to take variadic arguments even though we don't use them, as dev_fmt()
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* may only just have been expanded and may result in multiple arguments.
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*/
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#define dev_printk_index_emit(level, fmt, ...) \
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printk_index_subsys_emit("%s %s: ", level, fmt)
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#define dev_printk_index_wrap(_p_func, level, dev, fmt, ...) \
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({ \
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dev_printk_index_emit(level, fmt); \
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_p_func(dev, fmt, ##__VA_ARGS__); \
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})
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/*
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* Some callsites directly call dev_printk rather than going through the
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* dev_<level> infrastructure, so we need to emit here as well as inside those
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* level-specific macros. Only one index entry will be produced, either way,
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* since dev_printk's `fmt` isn't known at compile time if going through the
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* dev_<level> macros.
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*
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* dev_fmt() isn't called for dev_printk when used directly, as it's used by
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* the dev_<level> macros internally which already have dev_fmt() processed.
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*
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* We also can't use dev_printk_index_wrap directly, because we have a separate
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* level to process.
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*/
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#define dev_printk(level, dev, fmt, ...) \
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({ \
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dev_printk_index_emit(level, fmt); \
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_dev_printk(level, dev, fmt, ##__VA_ARGS__); \
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})
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/*
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* #defines for all the dev_<level> macros to prefix with whatever
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* possible use of #define dev_fmt(fmt) ...
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*/
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#define dev_emerg(dev, fmt, ...) \
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dev_printk_index_wrap(_dev_emerg, KERN_EMERG, dev, dev_fmt(fmt), ##__VA_ARGS__)
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#define dev_crit(dev, fmt, ...) \
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dev_printk_index_wrap(_dev_crit, KERN_CRIT, dev, dev_fmt(fmt), ##__VA_ARGS__)
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#define dev_alert(dev, fmt, ...) \
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dev_printk_index_wrap(_dev_alert, KERN_ALERT, dev, dev_fmt(fmt), ##__VA_ARGS__)
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#define dev_err(dev, fmt, ...) \
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dev_printk_index_wrap(_dev_err, KERN_ERR, dev, dev_fmt(fmt), ##__VA_ARGS__)
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#define dev_warn(dev, fmt, ...) \
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dev_printk_index_wrap(_dev_warn, KERN_WARNING, dev, dev_fmt(fmt), ##__VA_ARGS__)
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#define dev_notice(dev, fmt, ...) \
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dev_printk_index_wrap(_dev_notice, KERN_NOTICE, dev, dev_fmt(fmt), ##__VA_ARGS__)
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#define dev_info(dev, fmt, ...) \
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dev_printk_index_wrap(_dev_info, KERN_INFO, dev, dev_fmt(fmt), ##__VA_ARGS__)
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#if defined(CONFIG_DYNAMIC_DEBUG) || \
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(defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
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#define dev_dbg(dev, fmt, ...) \
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dynamic_dev_dbg(dev, dev_fmt(fmt), ##__VA_ARGS__)
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#elif defined(DEBUG)
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#define dev_dbg(dev, fmt, ...) \
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dev_printk(KERN_DEBUG, dev, dev_fmt(fmt), ##__VA_ARGS__)
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#else
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#define dev_dbg(dev, fmt, ...) \
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({ \
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if (0) \
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dev_printk(KERN_DEBUG, dev, dev_fmt(fmt), ##__VA_ARGS__); \
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})
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#endif
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#ifdef CONFIG_PRINTK
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#define dev_level_once(dev_level, dev, fmt, ...) \
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do { \
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static bool __print_once __read_mostly; \
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\
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if (!__print_once) { \
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__print_once = true; \
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dev_level(dev, fmt, ##__VA_ARGS__); \
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} \
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} while (0)
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#else
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#define dev_level_once(dev_level, dev, fmt, ...) \
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do { \
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if (0) \
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dev_level(dev, fmt, ##__VA_ARGS__); \
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} while (0)
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#endif
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#define dev_emerg_once(dev, fmt, ...) \
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dev_level_once(dev_emerg, dev, fmt, ##__VA_ARGS__)
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#define dev_alert_once(dev, fmt, ...) \
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dev_level_once(dev_alert, dev, fmt, ##__VA_ARGS__)
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#define dev_crit_once(dev, fmt, ...) \
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dev_level_once(dev_crit, dev, fmt, ##__VA_ARGS__)
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#define dev_err_once(dev, fmt, ...) \
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dev_level_once(dev_err, dev, fmt, ##__VA_ARGS__)
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#define dev_warn_once(dev, fmt, ...) \
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dev_level_once(dev_warn, dev, fmt, ##__VA_ARGS__)
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#define dev_notice_once(dev, fmt, ...) \
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dev_level_once(dev_notice, dev, fmt, ##__VA_ARGS__)
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#define dev_info_once(dev, fmt, ...) \
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dev_level_once(dev_info, dev, fmt, ##__VA_ARGS__)
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#define dev_dbg_once(dev, fmt, ...) \
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dev_level_once(dev_dbg, dev, fmt, ##__VA_ARGS__)
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#define dev_level_ratelimited(dev_level, dev, fmt, ...) \
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do { \
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static DEFINE_RATELIMIT_STATE(_rs, \
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DEFAULT_RATELIMIT_INTERVAL, \
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DEFAULT_RATELIMIT_BURST); \
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if (__ratelimit(&_rs)) \
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dev_level(dev, fmt, ##__VA_ARGS__); \
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} while (0)
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#define dev_emerg_ratelimited(dev, fmt, ...) \
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dev_level_ratelimited(dev_emerg, dev, fmt, ##__VA_ARGS__)
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#define dev_alert_ratelimited(dev, fmt, ...) \
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dev_level_ratelimited(dev_alert, dev, fmt, ##__VA_ARGS__)
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#define dev_crit_ratelimited(dev, fmt, ...) \
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dev_level_ratelimited(dev_crit, dev, fmt, ##__VA_ARGS__)
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#define dev_err_ratelimited(dev, fmt, ...) \
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dev_level_ratelimited(dev_err, dev, fmt, ##__VA_ARGS__)
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#define dev_warn_ratelimited(dev, fmt, ...) \
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dev_level_ratelimited(dev_warn, dev, fmt, ##__VA_ARGS__)
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#define dev_notice_ratelimited(dev, fmt, ...) \
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dev_level_ratelimited(dev_notice, dev, fmt, ##__VA_ARGS__)
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#define dev_info_ratelimited(dev, fmt, ...) \
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dev_level_ratelimited(dev_info, dev, fmt, ##__VA_ARGS__)
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#if defined(CONFIG_DYNAMIC_DEBUG) || \
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(defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
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/* descriptor check is first to prevent flooding with "callbacks suppressed" */
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#define dev_dbg_ratelimited(dev, fmt, ...) \
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do { \
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static DEFINE_RATELIMIT_STATE(_rs, \
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DEFAULT_RATELIMIT_INTERVAL, \
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DEFAULT_RATELIMIT_BURST); \
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DEFINE_DYNAMIC_DEBUG_METADATA(descriptor, fmt); \
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if (DYNAMIC_DEBUG_BRANCH(descriptor) && \
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__ratelimit(&_rs)) \
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__dynamic_dev_dbg(&descriptor, dev, dev_fmt(fmt), \
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##__VA_ARGS__); \
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} while (0)
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#elif defined(DEBUG)
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#define dev_dbg_ratelimited(dev, fmt, ...) \
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do { \
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static DEFINE_RATELIMIT_STATE(_rs, \
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DEFAULT_RATELIMIT_INTERVAL, \
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DEFAULT_RATELIMIT_BURST); \
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if (__ratelimit(&_rs)) \
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dev_printk(KERN_DEBUG, dev, dev_fmt(fmt), ##__VA_ARGS__); \
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} while (0)
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#else
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#define dev_dbg_ratelimited(dev, fmt, ...) \
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do { \
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if (0) \
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dev_printk(KERN_DEBUG, dev, dev_fmt(fmt), ##__VA_ARGS__); \
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} while (0)
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#endif
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#ifdef VERBOSE_DEBUG
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#define dev_vdbg dev_dbg
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#else
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#define dev_vdbg(dev, fmt, ...) \
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({ \
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if (0) \
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dev_printk(KERN_DEBUG, dev, dev_fmt(fmt), ##__VA_ARGS__); \
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})
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#endif
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/*
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* dev_WARN*() acts like dev_printk(), but with the key difference of
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* using WARN/WARN_ONCE to include file/line information and a backtrace.
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*/
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#define dev_WARN(dev, format, arg...) \
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WARN(1, "%s %s: " format, dev_driver_string(dev), dev_name(dev), ## arg)
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#define dev_WARN_ONCE(dev, condition, format, arg...) \
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WARN_ONCE(condition, "%s %s: " format, \
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dev_driver_string(dev), dev_name(dev), ## arg)
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#endif /* _DEVICE_PRINTK_H_ */
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