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author | Linus Torvalds <torvalds@linux-foundation.org> | 2009-02-19 17:14:22 (GMT) |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-02-19 17:14:22 (GMT) |
commit | f54b2fe4aef9aa74ddf2c856928c3e29f3371fe7 (patch) | |
tree | 8ca38b4fab7d2a9a5bfd26a2e640631d52894fe6 /kernel | |
parent | 83ff1af9d330348d1a6685b0c06d33847cd72723 (diff) | |
parent | ed4a2f374d71770796789ed559c35a36bab82f1a (diff) | |
download | linux-fsl-qoriq-f54b2fe4aef9aa74ddf2c856928c3e29f3371fe7.tar.xz |
Merge branch 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
tracing: limit the number of loops the ring buffer self test can make
tracing: have function trace select kallsyms
tracing: disable tracing while testing ring buffer
tracing/function-graph-tracer: trace the idle tasks
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/trace/Kconfig | 2 | ||||
-rw-r--r-- | kernel/trace/ftrace.c | 6 | ||||
-rw-r--r-- | kernel/trace/trace_selftest.c | 19 |
3 files changed, 26 insertions, 1 deletions
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 58a93fbd..34e707e 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -52,6 +52,7 @@ config FUNCTION_TRACER depends on HAVE_FUNCTION_TRACER depends on DEBUG_KERNEL select FRAME_POINTER + select KALLSYMS select TRACING select CONTEXT_SWITCH_TRACER help @@ -238,6 +239,7 @@ config STACK_TRACER depends on DEBUG_KERNEL select FUNCTION_TRACER select STACKTRACE + select KALLSYMS help This special tracer records the maximum stack footprint of the kernel and displays it in debugfs/tracing/stack_trace. diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 9a236ff..fdf913d 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2033,7 +2033,7 @@ free: static int start_graph_tracing(void) { struct ftrace_ret_stack **ret_stack_list; - int ret; + int ret, cpu; ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE * sizeof(struct ftrace_ret_stack *), @@ -2042,6 +2042,10 @@ static int start_graph_tracing(void) if (!ret_stack_list) return -ENOMEM; + /* The cpu_boot init_task->ret_stack will never be freed */ + for_each_online_cpu(cpu) + ftrace_graph_init_task(idle_task(cpu)); + do { ret = alloc_retstack_tasklist(ret_stack_list); } while (ret == -EAGAIN); diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c index 88c8eb7..bc8e80a 100644 --- a/kernel/trace/trace_selftest.c +++ b/kernel/trace/trace_selftest.c @@ -23,10 +23,20 @@ static int trace_test_buffer_cpu(struct trace_array *tr, int cpu) { struct ring_buffer_event *event; struct trace_entry *entry; + unsigned int loops = 0; while ((event = ring_buffer_consume(tr->buffer, cpu, NULL))) { entry = ring_buffer_event_data(event); + /* + * The ring buffer is a size of trace_buf_size, if + * we loop more than the size, there's something wrong + * with the ring buffer. + */ + if (loops++ > trace_buf_size) { + printk(KERN_CONT ".. bad ring buffer "); + goto failed; + } if (!trace_valid_entry(entry)) { printk(KERN_CONT ".. invalid entry %d ", entry->type); @@ -57,11 +67,20 @@ static int trace_test_buffer(struct trace_array *tr, unsigned long *count) cnt = ring_buffer_entries(tr->buffer); + /* + * The trace_test_buffer_cpu runs a while loop to consume all data. + * If the calling tracer is broken, and is constantly filling + * the buffer, this will run forever, and hard lock the box. + * We disable the ring buffer while we do this test to prevent + * a hard lock up. + */ + tracing_off(); for_each_possible_cpu(cpu) { ret = trace_test_buffer_cpu(tr, cpu); if (ret) break; } + tracing_on(); __raw_spin_unlock(&ftrace_max_lock); local_irq_restore(flags); |