I added a 'trace_event=*:*' to my command line and it crashed the system.
The reason was because it enabled the tracepoint benchmark which has
a reg function that creates a thread. But the kernel command line
tracepoint enabling is done before the scheduler is set up, and thus
the creation of a thread killed the kernel.
But then I noticed that there's no way for the reg to tell the calling
function that it failed to set up. I changed that so that it can fail
and notify the users that the tracepoint did not get enabled due to
a failure.
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
ftrace/core
Head SHA1: 9d08cef4a375e171008ed3a041e930aae20cc940
Steven Rostedt (Red Hat) (4):
tracing: Have the reg function allow to fail
tracing: Do not start benchmark on boot up
tracing: Have system enable return error if one of the events fail
tracing: Allow benchmark to be enabled at early_initcall()
----
arch/powerpc/include/asm/trace.h | 4 ++--
arch/powerpc/platforms/powernv/opal-tracepoints.c | 6 ++++--
arch/powerpc/platforms/pseries/lpar.c | 6 ++++--
arch/x86/include/asm/trace/exceptions.h | 2 +-
arch/x86/include/asm/trace/irq_vectors.h | 2 +-
arch/x86/kernel/tracepoint.c | 3 ++-
drivers/i2c/i2c-core.c | 3 ++-
include/linux/tracepoint-defs.h | 2 +-
include/linux/tracepoint.h | 2 +-
include/trace/events/i2c.h | 2 +-
kernel/trace/trace_benchmark.c | 26 +++++++++++++++++++++--
kernel/trace/trace_benchmark.h | 2 +-
kernel/trace/trace_events.c | 13 ++++++++++--
kernel/tracepoint.c | 12 ++++++++---
samples/trace_events/trace-events-sample.c | 3 ++-
samples/trace_events/trace-events-sample.h | 2 +-
16 files changed, 67 insertions(+), 23 deletions(-)
