diff options
| -rw-r--r-- | Documentation/kernel-parameters.txt | 18 | ||||
| -rw-r--r-- | include/linux/ftrace.h | 7 | ||||
| -rw-r--r-- | init/main.c | 4 | ||||
| -rw-r--r-- | kernel/sysctl.c | 7 | ||||
| -rw-r--r-- | kernel/trace/trace.c | 25 | ||||
| -rw-r--r-- | kernel/trace/trace.h | 14 | ||||
| -rw-r--r-- | kernel/trace/trace_events.c | 42 | ||||
| -rw-r--r-- | kernel/trace/trace_syscalls.c | 7 |
8 files changed, 116 insertions, 8 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 1de833556d22..bda85f1dbd44 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -3570,6 +3570,24 @@ bytes respectively. Such letter suffixes can also be entirely omitted. See also Documentation/trace/ftrace.txt "trace options" section. + tp_printk[FTRACE] + Have the tracepoints sent to printk as well as the + tracing ring buffer. This is useful for early boot up + where the system hangs or reboots and does not give the + option for reading the tracing buffer or performing a + ftrace_dump_on_oops. + + To turn off having tracepoints sent to printk, + echo 0 > /proc/sys/kernel/tracepoint_printk + Note, echoing 1 into this file without the + tracepoint_printk kernel cmdline option has no effect. + + ** CAUTION ** + + Having tracepoints sent to printk() and activating high + frequency tracepoints such as irq or sched, can cause + the system to live lock. + traceoff_on_warning [FTRACE] enable this option to disable tracing when a warning is hit. This turns off "tracing_on". Tracing can diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index ed501953f0b2..1da602982cf9 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -39,6 +39,12 @@ # define FTRACE_FORCE_LIST_FUNC 0 #endif +/* Main tracing buffer and events set up */ +#ifdef CONFIG_TRACING +void trace_init(void); +#else +static inline void trace_init(void) { } +#endif struct module; struct ftrace_hash; @@ -873,6 +879,7 @@ static inline int test_tsk_trace_graph(struct task_struct *tsk) enum ftrace_dump_mode; extern enum ftrace_dump_mode ftrace_dump_on_oops; +extern int tracepoint_printk; extern void disable_trace_on_warning(void); extern int __disable_trace_on_warning; diff --git a/init/main.c b/init/main.c index 8a914b758e5d..747ecc4c0a19 100644 --- a/init/main.c +++ b/init/main.c @@ -578,6 +578,10 @@ asmlinkage __visible void __init start_kernel(void) local_irq_disable(); idr_init_cache(); rcu_init(); + + /* trace_printk() and trace points may be used after this */ + trace_init(); + context_tracking_init(); radix_tree_init(); /* init some links before init_ISA_irqs() */ diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 7c54ff79afd7..137c7f69b264 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -623,6 +623,13 @@ static struct ctl_table kern_table[] = { .mode = 0644, .proc_handler = proc_dointvec, }, + { + .procname = "tracepoint_printk", + .data = &tracepoint_printk, + .maxlen = sizeof(tracepoint_printk), + .mode = 0644, + .proc_handler = proc_dointvec, + }, #endif #ifdef CONFIG_KEXEC { diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index ab76b7bcb36a..2e767972e99c 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -63,6 +63,10 @@ static bool __read_mostly tracing_selftest_running; */ bool __read_mostly tracing_selftest_disabled; +/* Pipe tracepoints to printk */ +struct trace_iterator *tracepoint_print_iter; +int tracepoint_printk; + /* For tracers that don't implement custom flags */ static struct tracer_opt dummy_tracer_opt[] = { { } @@ -193,6 +197,13 @@ static int __init set_trace_boot_clock(char *str) } __setup("trace_clock=", set_trace_boot_clock); +static int __init set_tracepoint_printk(char *str) +{ + if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0)) + tracepoint_printk = 1; + return 1; +} +__setup("tp_printk", set_tracepoint_printk); unsigned long long ns2usecs(cycle_t nsec) { @@ -6898,6 +6909,19 @@ out: return ret; } +void __init trace_init(void) +{ + if (tracepoint_printk) { + tracepoint_print_iter = + kmalloc(sizeof(*tracepoint_print_iter), GFP_KERNEL); + if (WARN_ON(!tracepoint_print_iter)) + tracepoint_printk = 0; + } + tracer_alloc_buffers(); + init_ftrace_syscalls(); + trace_event_init(); +} + __init static int clear_boot_tracer(void) { /* @@ -6917,6 +6941,5 @@ __init static int clear_boot_tracer(void) return 0; } -early_initcall(tracer_alloc_buffers); fs_initcall(tracer_init_debugfs); late_initcall(clear_boot_tracer); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 3255dfb054a0..8de48bac1ce2 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -1301,4 +1301,18 @@ int perf_ftrace_event_register(struct ftrace_event_call *call, #define perf_ftrace_event_register NULL #endif +#ifdef CONFIG_FTRACE_SYSCALLS +void init_ftrace_syscalls(void); +#else +static inline void init_ftrace_syscalls(void) { } +#endif + +#ifdef CONFIG_EVENT_TRACING +void trace_event_init(void); +#else +static inline void __init trace_event_init(void) { } +#endif + +extern struct trace_iterator *tracepoint_print_iter; + #endif /* _LINUX_KERNEL_TRACE_H */ diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index d0e4f92b5eb6..366a78a3e61e 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -212,8 +212,40 @@ void *ftrace_event_buffer_reserve(struct ftrace_event_buffer *fbuffer, } EXPORT_SYMBOL_GPL(ftrace_event_buffer_reserve); +static DEFINE_SPINLOCK(tracepoint_iter_lock); + +static void output_printk(struct ftrace_event_buffer *fbuffer) +{ + struct ftrace_event_call *event_call; + struct trace_event *event; + unsigned long flags; + struct trace_iterator *iter = tracepoint_print_iter; + + if (!iter) + return; + + event_call = fbuffer->ftrace_file->event_call; + if (!event_call || !event_call->event.funcs || + !event_call->event.funcs->trace) + return; + + event = &fbuffer->ftrace_file->event_call->event; + + spin_lock_irqsave(&tracepoint_iter_lock, flags); + trace_seq_init(&iter->seq); + iter->ent = fbuffer->entry; + event_call->event.funcs->trace(iter, 0, event); + trace_seq_putc(&iter->seq, 0); + printk("%s", iter->seq.buffer); + + spin_unlock_irqrestore(&tracepoint_iter_lock, flags); +} + void ftrace_event_buffer_commit(struct ftrace_event_buffer *fbuffer) { + if (tracepoint_printk) + output_printk(fbuffer); + event_trigger_unlock_commit(fbuffer->ftrace_file, fbuffer->buffer, fbuffer->event, fbuffer->entry, fbuffer->flags, fbuffer->pc); @@ -2480,8 +2512,14 @@ static __init int event_trace_init(void) #endif return 0; } -early_initcall(event_trace_memsetup); -core_initcall(event_trace_enable); + +void __init trace_event_init(void) +{ + event_trace_memsetup(); + init_ftrace_syscalls(); + event_trace_enable(); +} + fs_initcall(event_trace_init); #ifdef CONFIG_FTRACE_STARTUP_TEST diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index dfe00a4f3f3e..c6ee36fcbf90 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -514,7 +514,7 @@ unsigned long __init __weak arch_syscall_addr(int nr) return (unsigned long)sys_call_table[nr]; } -static int __init init_ftrace_syscalls(void) +void __init init_ftrace_syscalls(void) { struct syscall_metadata *meta; unsigned long addr; @@ -524,7 +524,7 @@ static int __init init_ftrace_syscalls(void) GFP_KERNEL); if (!syscalls_metadata) { WARN_ON(1); - return -ENOMEM; + return; } for (i = 0; i < NR_syscalls; i++) { @@ -536,10 +536,7 @@ static int __init init_ftrace_syscalls(void) meta->syscall_nr = i; syscalls_metadata[i] = meta; } - - return 0; } -early_initcall(init_ftrace_syscalls); #ifdef CONFIG_PERF_EVENTS |