From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Gleixner Subject: [patch V2 01/29] tracing: Cleanup stack trace code Date: Thu, 18 Apr 2019 10:41:20 +0200 Message-ID: <20190418084253.142712304@linutronix.de> References: <20190418084119.056416939@linutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: LKML Cc: Mike Snitzer , David Airlie , Catalin Marinas , Joonas Lahtinen , dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, dm-devel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, Alexander Potapenko , Christoph Lameter , Christoph Hellwig , Alasdair Kergon , linux-arch-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, kasan-dev-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org, Johannes Thumshirn , Andrey Ryabinin , Alexey Dobriyan , intel-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org, David Rientjes , Maarten Lankhorst , Akinobu Mita , Steven Rostedt , Josef Bacik , Rodrigo Vivi , Mike Rapoport List-Id: intel-gfx@lists.freedesktop.org - Remove the extra array member of stack_dump_trace[]. It's not required as the stack tracer stores at max array size - 1 entries so there is still an empty slot. - Make variables which are only used in trace_stack.c static. - Simplify the enable/disable logic. - Rename stack_trace_print() as it's using the stack_trace_ namespace. Free the name up for stack trace related functions. Signed-off-by: Thomas Gleixner Cc: Steven Rostedt --- V2: Add more cleanups and use print_max_stack() as requested by Steven. --- include/linux/ftrace.h | 18 ++++-------------- kernel/trace/trace_stack.c | 36 ++++++++++++------------------------ 2 files changed, 16 insertions(+), 38 deletions(-) --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -241,21 +241,11 @@ static inline void ftrace_free_mem(struc #ifdef CONFIG_STACK_TRACER -#define STACK_TRACE_ENTRIES 500 - -struct stack_trace; - -extern unsigned stack_trace_index[]; -extern struct stack_trace stack_trace_max; -extern unsigned long stack_trace_max_size; -extern arch_spinlock_t stack_trace_max_lock; - extern int stack_tracer_enabled; -void stack_trace_print(void); -int -stack_trace_sysctl(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, - loff_t *ppos); + +int stack_trace_sysctl(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, + loff_t *ppos); /* DO NOT MODIFY THIS VARIABLE DIRECTLY! */ DECLARE_PER_CPU(int, disable_stack_tracer); --- a/kernel/trace/trace_stack.c +++ b/kernel/trace/trace_stack.c @@ -18,8 +18,10 @@ #include "trace.h" -static unsigned long stack_dump_trace[STACK_TRACE_ENTRIES + 1]; -unsigned stack_trace_index[STACK_TRACE_ENTRIES]; +#define STACK_TRACE_ENTRIES 500 + +static unsigned long stack_dump_trace[STACK_TRACE_ENTRIES]; +static unsigned stack_trace_index[STACK_TRACE_ENTRIES]; /* * Reserve one entry for the passed in ip. This will allow @@ -31,17 +33,16 @@ struct stack_trace stack_trace_max = { .entries = &stack_dump_trace[0], }; -unsigned long stack_trace_max_size; -arch_spinlock_t stack_trace_max_lock = +static unsigned long stack_trace_max_size; +static arch_spinlock_t stack_trace_max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; DEFINE_PER_CPU(int, disable_stack_tracer); static DEFINE_MUTEX(stack_sysctl_mutex); int stack_tracer_enabled; -static int last_stack_tracer_enabled; -void stack_trace_print(void) +static void print_max_stack(void) { long i; int size; @@ -61,16 +62,7 @@ void stack_trace_print(void) } } -/* - * When arch-specific code overrides this function, the following - * data should be filled up, assuming stack_trace_max_lock is held to - * prevent concurrent updates. - * stack_trace_index[] - * stack_trace_max - * stack_trace_max_size - */ -void __weak -check_stack(unsigned long ip, unsigned long *stack) +static void check_stack(unsigned long ip, unsigned long *stack) { unsigned long this_size, flags; unsigned long *p, *top, *start; static int tracer_frame; @@ -179,7 +171,7 @@ check_stack(unsigned long ip, unsigned l stack_trace_max.nr_entries = x; if (task_stack_end_corrupted(current)) { - stack_trace_print(); + print_max_stack(); BUG(); } @@ -412,23 +404,20 @@ stack_trace_sysctl(struct ctl_table *tab void __user *buffer, size_t *lenp, loff_t *ppos) { - int ret; + int ret, was_enabled; mutex_lock(&stack_sysctl_mutex); + was_enabled = !!stack_tracer_enabled; ret = proc_dointvec(table, write, buffer, lenp, ppos); - if (ret || !write || - (last_stack_tracer_enabled == !!stack_tracer_enabled)) + if (ret || !write || (was_enabled == !!stack_tracer_enabled)) goto out; - last_stack_tracer_enabled = !!stack_tracer_enabled; - if (stack_tracer_enabled) register_ftrace_function(&trace_ops); else unregister_ftrace_function(&trace_ops); - out: mutex_unlock(&stack_sysctl_mutex); return ret; @@ -444,7 +433,6 @@ static __init int enable_stacktrace(char strncpy(stack_trace_filter_buf, str + len, COMMAND_LINE_SIZE); stack_tracer_enabled = 1; - last_stack_tracer_enabled = 1; return 1; } __setup("stacktrace", enable_stacktrace);