From 3fff4c42bd0a89869a0eb1e7874cc06ffa4aa0f5 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Tue, 22 Sep 2009 16:18:09 +0200 Subject: printk: Remove ratelimit.h from kernel.h Decouple kernel.h from ratelimit.h: the global declaration of printk's ratelimit_state is not needed, and it leads to messy circular dependencies due to ratelimit.h's (new) adding of a spinlock_types.h include. Cc: Peter Zijlstra Cc: Andrew Morton Cc: Linus Torvalds Cc: David S. Miller LKML-Reference: Signed-off-by: Ingo Molnar --- include/linux/kernel.h | 2 -- 1 file changed, 2 deletions(-) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 2b5b1e0899a..3305f33201b 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -15,7 +15,6 @@ #include #include #include -#include #include #include #include @@ -241,7 +240,6 @@ asmlinkage int vprintk(const char *fmt, va_list args) asmlinkage int printk(const char * fmt, ...) __attribute__ ((format (printf, 1, 2))) __cold; -extern struct ratelimit_state printk_ratelimit_state; extern int printk_ratelimit(void); extern bool printk_timed_ratelimit(unsigned long *caller_jiffies, unsigned int interval_msec); -- cgit v1.2.3-70-g09d2 From 5c828713358cb9df8aa174371edcbbb62203a490 Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Fri, 23 Oct 2009 14:58:11 +0200 Subject: ratelimit: Make suppressed output messages more useful Today I got: [39648.224782] Registered led device: iwl-phy0::TX [40676.545099] __ratelimit: 246 callbacks suppressed [40676.545103] abcdef[23675]: segfault at 0 ... as you can see the ratelimit message contains a function prefix. Since this is always __ratelimit, this wont help much. This patch changes __ratelimit and printk_ratelimit to print the function name that calls ratelimit. This will pinpoint the responsible function, as long as not several different places call ratelimit with the same ratelimit state at the same time. In that case we catch only one random function that calls ratelimit after the wait period. Signed-off-by: Christian Borntraeger Cc: Dave Young Cc: Linus Torvalds CC: Andrew Morton LKML-Reference: <200910231458.11832.borntraeger@de.ibm.com> Signed-off-by: Ingo Molnar --- include/linux/kernel.h | 3 ++- include/linux/ratelimit.h | 3 ++- kernel/printk.c | 6 +++--- lib/ratelimit.c | 6 +++--- 4 files changed, 10 insertions(+), 8 deletions(-) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 3305f33201b..21d0d822c71 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -240,7 +240,8 @@ asmlinkage int vprintk(const char *fmt, va_list args) asmlinkage int printk(const char * fmt, ...) __attribute__ ((format (printf, 1, 2))) __cold; -extern int printk_ratelimit(void); +extern int __printk_ratelimit(const char *func); +#define printk_ratelimit() __printk_ratelimit(__func__) extern bool printk_timed_ratelimit(unsigned long *caller_jiffies, unsigned int interval_msec); diff --git a/include/linux/ratelimit.h b/include/linux/ratelimit.h index 187bc16c1f1..668cf1bef03 100644 --- a/include/linux/ratelimit.h +++ b/include/linux/ratelimit.h @@ -25,6 +25,7 @@ struct ratelimit_state { .burst = burst_init, \ } -extern int __ratelimit(struct ratelimit_state *rs); +extern int ___ratelimit(struct ratelimit_state *rs, const char *func); +#define __ratelimit(state) ___ratelimit(state, __func__) #endif /* _LINUX_RATELIMIT_H */ diff --git a/kernel/printk.c b/kernel/printk.c index b997c893cdc..8283dbe15af 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -1364,11 +1364,11 @@ late_initcall(disable_boot_consoles); */ DEFINE_RATELIMIT_STATE(printk_ratelimit_state, 5 * HZ, 10); -int printk_ratelimit(void) +int __printk_ratelimit(const char *func) { - return __ratelimit(&printk_ratelimit_state); + return ___ratelimit(&printk_ratelimit_state, func); } -EXPORT_SYMBOL(printk_ratelimit); +EXPORT_SYMBOL(__printk_ratelimit); /** * printk_timed_ratelimit - caller-controlled printk ratelimiting diff --git a/lib/ratelimit.c b/lib/ratelimit.c index 5551731ae1d..09f5ce1810d 100644 --- a/lib/ratelimit.c +++ b/lib/ratelimit.c @@ -20,7 +20,7 @@ * This enforces a rate limit: not more than @rs->ratelimit_burst callbacks * in every @rs->ratelimit_jiffies */ -int __ratelimit(struct ratelimit_state *rs) +int ___ratelimit(struct ratelimit_state *rs, const char *func) { unsigned long flags; int ret; @@ -43,7 +43,7 @@ int __ratelimit(struct ratelimit_state *rs) if (time_is_before_jiffies(rs->begin + rs->interval)) { if (rs->missed) printk(KERN_WARNING "%s: %d callbacks suppressed\n", - __func__, rs->missed); + func, rs->missed); rs->begin = 0; rs->printed = 0; rs->missed = 0; @@ -59,4 +59,4 @@ int __ratelimit(struct ratelimit_state *rs) return ret; } -EXPORT_SYMBOL(__ratelimit); +EXPORT_SYMBOL(___ratelimit); -- cgit v1.2.3-70-g09d2 From 03889384cee7a198a79447c1ea6aca2c8e54d155 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 11 Dec 2009 09:48:22 -0500 Subject: tracing: Add trace_dump_stack() I've been asked a few times about how to find out what is calling some location in the kernel. One way is to use dynamic function tracing and implement the func_stack_trace. But this only finds out who is calling a particular function. It does not tell you who is calling that function and entering a specific if conditional. I have myself implemented a quick version of trace_dump_stack() for this purpose a few times, and just needed it now. This is when I realized that this would be a good tool to have in the kernel like trace_printk(). Using trace_dump_stack() is similar to dump_stack() except that it writes to the trace buffer instead and can be used in critical locations. For example: @@ -5485,8 +5485,12 @@ need_resched_nonpreemptible: if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { if (unlikely(signal_pending_state(prev->state, prev))) prev->state = TASK_RUNNING; - else + else { deactivate_task(rq, prev, 1); + trace_printk("Deactivating task %s:%d\n", + prev->comm, prev->pid); + trace_dump_stack(); + } switch_count = &prev->nvcsw; } Produces: <...>-3249 [001] 296.105269: schedule: Deactivating task ntpd:3249 <...>-3249 [001] 296.105270: => schedule => schedule_hrtimeout_range => poll_schedule_timeout => do_select => core_sys_select => sys_select => system_call_fastpath Signed-off-by: Steven Rostedt --- include/linux/kernel.h | 2 ++ kernel/trace/trace.c | 16 ++++++++++++++++ 2 files changed, 18 insertions(+) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 3fa4c590cf1..5ad4199fb07 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -492,6 +492,8 @@ extern int __trace_printk(unsigned long ip, const char *fmt, ...) __attribute__ ((format (printf, 2, 3))); +extern void trace_dump_stack(void); + /* * The double __builtin_constant_p is because gcc will give us an error * if we try to allocate the static variable to fmt if it is not a diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 88bd9ae2a9e..f531301b7a3 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1151,6 +1151,22 @@ void __trace_stack(struct trace_array *tr, unsigned long flags, int skip, __ftrace_trace_stack(tr->buffer, flags, skip, pc); } +/** + * trace_dump_stack - record a stack back trace in the trace buffer + */ +void trace_dump_stack(void) +{ + unsigned long flags; + + if (tracing_disabled || tracing_selftest_running) + return 0; + + local_save_flags(flags); + + /* skipping 3 traces, seems to get us at the caller of this function */ + __ftrace_trace_stack(global_trace.buffer, flags, 3, preempt_count()); +} + void ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc) { -- cgit v1.2.3-70-g09d2 From e36c54582c6f14adc9e10473e2aec2cc4f0acc03 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 14 Dec 2009 15:58:33 -0500 Subject: tracing: Fix return of trace_dump_stack() The trace_dump_stack() returned a value for a void function. Also, added the missing stub for trace_dump_stack() when tracing is not configured. Reported-by: Ingo Molnar LKML-Reference: <20091214162713.GA31060@elte.hu> Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- include/linux/kernel.h | 1 + kernel/trace/trace.c | 2 +- 2 files changed, 2 insertions(+), 1 deletion(-) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 5ad4199fb07..f1dc752da0d 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -527,6 +527,7 @@ trace_printk(const char *fmt, ...) __attribute__ ((format (printf, 1, 2))); static inline void tracing_start(void) { } static inline void tracing_stop(void) { } static inline void ftrace_off_permanent(void) { } +static inline void trace_dump_stack(void) { } static inline int trace_printk(const char *fmt, ...) { diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index bd7b969a729..ee61915935d 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1158,7 +1158,7 @@ void trace_dump_stack(void) unsigned long flags; if (tracing_disabled || tracing_selftest_running) - return 0; + return; local_save_flags(flags); -- cgit v1.2.3-70-g09d2 From 00b55864bb37200d7f05143c44f5e2edfc8c4578 Mon Sep 17 00:00:00 2001 From: Joe Perches Date: Mon, 14 Dec 2009 18:00:14 -0800 Subject: dynamic_debug.h/kernel.h: Remove KBUILD_MODNAME from dynamic_pr_debug If CONFIG_DYNAMIC_DEBUG is enabled and a source file has: #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include dynamic_debug.h will duplicate KBUILD_MODNAME in the output string. Remove the use of KBUILD_MODNAME from the output format string generated by dynamic_debug.h If CONFIG_DYNAMIC_DEBUG is not enabled, no compile-time check is done to printk/dev_printk arguments. Add it. Signed-off-by: Joe Perches Cc: Jason Baron Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/dynamic_debug.h | 13 ++++++------- include/linux/kernel.h | 5 ++--- 2 files changed, 8 insertions(+), 10 deletions(-) (limited to 'include/linux/kernel.h') diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h index a0d9422a156..f8c2e176750 100644 --- a/include/linux/dynamic_debug.h +++ b/include/linux/dynamic_debug.h @@ -57,8 +57,7 @@ extern int ddebug_remove_module(char *mod_name); { KBUILD_MODNAME, __func__, __FILE__, fmt, DEBUG_HASH, \ DEBUG_HASH2, __LINE__, _DPRINTK_FLAGS_DEFAULT }; \ if (__dynamic_dbg_enabled(descriptor)) \ - printk(KERN_DEBUG KBUILD_MODNAME ":" pr_fmt(fmt), \ - ##__VA_ARGS__); \ + printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); \ } while (0) @@ -69,9 +68,7 @@ extern int ddebug_remove_module(char *mod_name); { KBUILD_MODNAME, __func__, __FILE__, fmt, DEBUG_HASH, \ DEBUG_HASH2, __LINE__, _DPRINTK_FLAGS_DEFAULT }; \ if (__dynamic_dbg_enabled(descriptor)) \ - dev_printk(KERN_DEBUG, dev, \ - KBUILD_MODNAME ": " fmt, \ - ##__VA_ARGS__); \ + dev_printk(KERN_DEBUG, dev, fmt, ##__VA_ARGS__); \ } while (0) #else @@ -81,8 +78,10 @@ static inline int ddebug_remove_module(char *mod) return 0; } -#define dynamic_pr_debug(fmt, ...) do { } while (0) -#define dynamic_dev_dbg(dev, format, ...) do { } while (0) +#define dynamic_pr_debug(fmt, ...) \ + do { if (0) printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); } while (0) +#define dynamic_dev_dbg(dev, format, ...) \ + do { if (0) dev_printk(KERN_DEBUG, dev, fmt, ##__VA_ARGS__); } while (0) #endif #endif diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 3fa4c590cf1..a93cdd031ae 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -397,9 +397,8 @@ static inline char *pack_hex_byte(char *buf, u8 byte) printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__) #elif defined(CONFIG_DYNAMIC_DEBUG) /* dynamic_pr_debug() uses pr_fmt() internally so we don't need it here */ -#define pr_debug(fmt, ...) do { \ - dynamic_pr_debug(fmt, ##__VA_ARGS__); \ - } while (0) +#define pr_debug(fmt, ...) \ + dynamic_pr_debug(fmt, ##__VA_ARGS__) #else #define pr_debug(fmt, ...) \ ({ if (0) printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); 0; }) -- cgit v1.2.3-70-g09d2 From 0b2749aa6ca40ff3fe12ebb3fdf010ebad2e9085 Mon Sep 17 00:00:00 2001 From: Joe Perches Date: Mon, 14 Dec 2009 18:00:19 -0800 Subject: kernel.h: remove initialization of bool in printk_once Don't initialize __print_once. Invert the test to reduce initialized data. defconfig before: $size vmlinux text data bss dec hex filename 6976022 679572 1359668 9015262 898fde vmlinux defconfig after: $size vmlinux text data bss dec hex filename 6976006 679508 1359700 9015214 898fae vmlinux Signed-off-by: Joe Perches Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kernel.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index a93cdd031ae..910db75b1a7 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -251,10 +251,10 @@ extern int printk_delay_msec; * Print a one-time message (analogous to WARN_ONCE() et al): */ #define printk_once(x...) ({ \ - static bool __print_once = true; \ + static bool __print_once; \ \ - if (__print_once) { \ - __print_once = false; \ + if (!__print_once) { \ + __print_once = true; \ printk(x); \ } \ }) -- cgit v1.2.3-70-g09d2 From 8a64f336bc1d4aa203b138d29d5a9c414a9fbb47 Mon Sep 17 00:00:00 2001 From: Joe Perches Date: Mon, 14 Dec 2009 18:00:25 -0800 Subject: kernel.h: add printk_ratelimited and pr__rl Add a printk_ratelimited statement expression macro that uses a per-call ratelimit_state so that multiple subsystems output messages are not suppressed by a global __ratelimit state. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: s/_rl/_ratelimited/g] Signed-off-by: Joe Perches Cc: Naohiro Ooiwa Cc: Ingo Molnar Cc: Hiroshi Shimamoto Cc: Peter Zijlstra Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kernel.h | 44 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 910db75b1a7..4d9c916d06d 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -404,6 +404,50 @@ static inline char *pack_hex_byte(char *buf, u8 byte) ({ if (0) printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); 0; }) #endif +/* + * ratelimited messages with local ratelimit_state, + * no local ratelimit_state used in the !PRINTK case + */ +#ifdef CONFIG_PRINTK +#define printk_ratelimited(fmt, ...) ({ \ + static struct ratelimit_state _rs = { \ + .interval = DEFAULT_RATELIMIT_INTERVAL, \ + .burst = DEFAULT_RATELIMIT_BURST, \ + }; \ + \ + if (!__ratelimit(&_rs)) \ + printk(fmt, ##__VA_ARGS__); \ +}) +#else +/* No effect, but we still get type checking even in the !PRINTK case: */ +#define printk_ratelimited printk +#endif + +#define pr_emerg_ratelimited(fmt, ...) \ + printk_ratelimited(KERN_EMERG pr_fmt(fmt), ##__VA_ARGS__) +#define pr_alert_ratelimited(fmt, ...) \ + printk_ratelimited(KERN_ALERT pr_fmt(fmt), ##__VA_ARGS__) +#define pr_crit_ratelimited(fmt, ...) \ + printk_ratelimited(KERN_CRIT pr_fmt(fmt), ##__VA_ARGS__) +#define pr_err_ratelimited(fmt, ...) \ + printk_ratelimited(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__) +#define pr_warning_ratelimited(fmt, ...) \ + printk_ratelimited(KERN_WARNING pr_fmt(fmt), ##__VA_ARGS__) +#define pr_notice_ratelimited(fmt, ...) \ + printk_ratelimited(KERN_NOTICE pr_fmt(fmt), ##__VA_ARGS__) +#define pr_info_ratelimited(fmt, ...) \ + printk_ratelimited(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__) +/* no pr_cont_ratelimited, don't do that... */ +/* If you are writing a driver, please use dev_dbg instead */ +#if defined(DEBUG) +#define pr_debug_ratelimited(fmt, ...) \ + printk_ratelimited(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__) +#else +#define pr_debug_ratelimited(fmt, ...) \ + ({ if (0) printk_ratelimited(KERN_DEBUG pr_fmt(fmt), \ + ##__VA_ARGS__); 0; }) +#endif + /* * General tracing related utility functions - trace_printk(), * tracing_on/tracing_off and tracing_start()/tracing_stop -- cgit v1.2.3-70-g09d2 From cc8ef6eb21e964b1c5eb97b2d0e8ac9893e1bf86 Mon Sep 17 00:00:00 2001 From: Roland Dreier Date: Fri, 15 Jan 2010 17:01:22 -0800 Subject: kernel.h: add BUILD_BUG_ON_NOT_POWER_OF_2() Add BUILD_BUG_ON_NOT_POWER_OF_2() When code relies on a constant being a power of 2: #define FOO 512 /* must be a power of 2 */ it would be nice to be able to do: BUILD_BUG_ON(!is_power_of_2(FOO)); However applying an inline function does not result in a compile-time constant that can be used with BUILD_BUG_ON(), so trying that gives results in: error: bit-field '' width not an integer constant As suggested by akpm, rather than monkeying around with is_power_of_2() and risking gcc warts about constant expressions, just create a macro BUILD_BUG_ON_NOT_POWER_OF_2() to encapsulate this common requirement. Signed-off-by: Roland Dreier Cc: Bart Van Assche Cc: David Dillow Cc: "Robert P. J. Day" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kernel.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 3fc9f5aab5f..328bca609b9 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -734,6 +734,10 @@ struct sysinfo { /* Force a compilation error if condition is constant and true */ #define MAYBE_BUILD_BUG_ON(cond) ((void)sizeof(char[1 - 2 * !!(cond)])) +/* Force a compilation error if a constant expression is not a power of 2 */ +#define BUILD_BUG_ON_NOT_POWER_OF_2(n) \ + BUILD_BUG_ON((n) == 0 || (((n) & ((n) - 1)) != 0)) + /* Force a compilation error if condition is true, but also produce a result (of value 0 and type size_t), so the expression can be used e.g. in a structure initializer (or where-ever else comma expressions -- cgit v1.2.3-70-g09d2