diff options
author | Ingo Molnar <mingo@elte.hu> | 2009-02-22 20:05:19 +0100 |
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committer | Ingo Molnar <mingo@elte.hu> | 2009-02-22 20:05:19 +0100 |
commit | fc6fc7f1b1095b92d4834e69b385b91e412a7ce5 (patch) | |
tree | 2ad451d5dac4d460830536944cef1de93be36b2a /kernel/trace/trace_selftest.c | |
parent | ef1f87aa7ba6224bef1b750b3272ba281d8f43ed (diff) | |
parent | 770824bdc421ff58a64db608294323571c949f4c (diff) |
Merge branch 'linus' into x86/apic
Conflicts:
arch/x86/mach-default/setup.c
Semantic conflict resolution:
arch/x86/kernel/setup.c
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/trace/trace_selftest.c')
-rw-r--r-- | kernel/trace/trace_selftest.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c index 88c8eb70f54a..bc8e80a86bca 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); |