linux/kernel/trace/trace_uprobe.c, branch v3.13

tracing: Update event filters for multibuffer

2013-11-05T21:50:20Z

The trace event filters are still tied to event calls rather than event files, which means you don't get what you'd expect when using filters in the multibuffer case: Before: # echo 'bytes_alloc > 8192' > /sys/kernel/debug/tracing/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 8192 # mkdir /sys/kernel/debug/tracing/instances/test1 # echo 'bytes_alloc > 2048' > /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 2048 # cat /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter bytes_alloc > 2048 Setting the filter in tracing/instances/test1/events shouldn't affect the same event in tracing/events as it does above. After: # echo 'bytes_alloc > 8192' > /sys/kernel/debug/tracing/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 8192 # mkdir /sys/kernel/debug/tracing/instances/test1 # echo 'bytes_alloc > 2048' > /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/filter bytes_alloc > 8192 # cat /sys/kernel/debug/tracing/instances/test1/events/kmem/kmalloc/filter bytes_alloc > 2048 We'd like to just move the filter directly from ftrace_event_call to ftrace_event_file, but there are a couple cases that don't yet have multibuffer support and therefore have to continue using the current event_call-based filters. For those cases, a new USE_CALL_FILTER bit is added to the event_call flags, whose main purpose is to keep the old behavior for those cases until they can be updated with multibuffer support; at that point, the USE_CALL_FILTER flag (and the new associated call_filter_check_discard() function) can go away. The multibuffer support also made filter_current_check_discard() redundant, so this change removes that function as well and replaces it with filter_check_discard() (or call_filter_check_discard() as appropriate). Link: http://lkml.kernel.org/r/f16e9ce4270c62f46b2e966119225e1c3cca7e60.1382620672.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi Signed-off-by: Steven Rostedt

tracing/uprobes: Fail to unregister if probe event files are in use

2013-08-01T22:25:50Z

Uprobes suffer the same problem that kprobes have. There's a race between writing to the "enable" file and removing the probe. The probe checks for it being in use and if it is not, goes about deleting the probe and the event that represents it. But the problem with that is, after it checks if it is in use it can be enabled, and the deletion of the event (access to the probe) will fail, as it is in use. But the uprobe will still be deleted. This is a problem as the event can reference the uprobe that was deleted. The fix is to remove the event first, and check to make sure the event removal succeeds. Then it is safe to remove the probe. When the event exists, either ftrace or perf can enable the probe and prevent the event from being removed. Link: http://lkml.kernel.org/r/20130704034038.991525256@goodmis.org Acked-by: Oleg Nesterov Signed-off-by: Steven Rostedt

tracing/perf: Move the PERF_MAX_TRACE_SIZE check into perf_trace_buf_prepare()

2013-07-19T01:31:28Z

Every perf_trace_buf_prepare() caller does WARN_ONCE(size > PERF_MAX_TRACE_SIZE, message) and "message" is almost the same. Shift this WARN_ONCE() into perf_trace_buf_prepare(). This changes the meaning of _ONCE, but I think this is fine. - 4947014 2932448 10104832 17984294 1126b26 vmlinux + 4948422 2932448 10104832 17985702 11270a6 vmlinux on my build. Link: http://lkml.kernel.org/r/20130617170211.GA19813@redhat.com Acked-by: Peter Zijlstra Signed-off-by: Oleg Nesterov Signed-off-by: Steven Rostedt

uprobes: Fix return value in error handling path

2013-07-03T00:42:29Z

When wrong argument is passed into uprobe_events it does not return an error: [root@jovi tracing]# echo 'p:myprobe /bin/bash' > uprobe_events [root@jovi tracing]# The proper response is: [root@jovi tracing]# echo 'p:myprobe /bin/bash' > uprobe_events -bash: echo: write error: Invalid argument Link: http://lkml.kernel.org/r/51B964FF.5000106@huawei.com Cc: Frederic Weisbecker Cc: Cc: stable@vger.kernel.org # 3.5+ Signed-off-by: zhangwei(Jovi) Signed-off-by: Steven Rostedt

uprobes/perf: Avoid perf_trace_buf_prepare/submit if ->perf_events is empty

2013-04-15T15:39:52Z

perf_trace_buf_prepare() + perf_trace_buf_submit() make no sense if this task/CPU has no active counters. Change uprobe_perf_print() to return if hlist_empty(call->perf_events). Note: this is not uprobe-specific, we can change other users too. Signed-off-by: Oleg Nesterov

uprobes/tracing: Don't pass addr=ip to perf_trace_buf_submit()

2013-04-13T13:32:04Z

uprobe_perf_print() passes addr=ip to perf_trace_buf_submit() for no reason. This sets perf_sample_data->addr for PERF_SAMPLE_ADDR, we already have perf_sample_data->ip initialized if PERF_SAMPLE_IP. Signed-off-by: Oleg Nesterov Acked-by: Masami Hiramatsu Acked-by: Srikar Dronamraju

uprobes/tracing: Change create_trace_uprobe() to support uretprobes

2013-04-13T13:32:03Z

Finally change create_trace_uprobe() to check if argv[0][0] == 'r' and pass the correct "is_ret" to alloc_trace_uprobe(). Signed-off-by: Oleg Nesterov Acked-by: Srikar Dronamraju Tested-by: Anton Arapov

uprobes/tracing: Make seq_printf() code uretprobe-friendly

2013-04-13T13:32:03Z

Change probes_seq_show() and print_uprobe_event() to check is_ret_probe() and print the correct data. Signed-off-by: Oleg Nesterov Acked-by: Srikar Dronamraju Tested-by: Anton Arapov

uprobes/tracing: Make register_uprobe_event() paths uretprobe-friendly

2013-04-13T13:32:03Z

Change uprobe_event_define_fields(), and __set_print_fmt() to check is_ret_probe() and use the appropriate format/fields. Signed-off-by: Oleg Nesterov Acked-by: Srikar Dronamraju Tested-by: Anton Arapov

uprobes/tracing: Make uprobe_{trace,perf}_print() uretprobe-friendly

2013-04-13T13:32:03Z

Change uprobe_trace_print() and uprobe_perf_print() to check is_ret_probe() and fill ring_buffer_event accordingly. Also change uprobe_trace_func() and uprobe_perf_func() to not _print() if is_ret_probe() is true. Note that we keep ->handler() nontrivial even for uretprobe, we need this for filtering and for other potential extensions. Signed-off-by: Oleg Nesterov Acked-by: Srikar Dronamraju Tested-by: Anton Arapov