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20dc3847cc
Fix boottime kprobe events to report and abort after each failure when
adding probes.
As an example, when we try to set multiprobe kprobe events in
bootconfig like this:
ftrace.event.kprobes.vfsevents {
probes = "vfs_read $arg1 $arg2,,
!error! not reported;?", // leads to error
"vfs_write $arg1 $arg2"
}
This will not work as expected. After
commit da0f1f4167 ("tracing/boottime: Fix kprobe event API usage"),
the function trace_boot_add_kprobe_event will not produce any error
message when adding a probe fails at kprobe_event_gen_cmd_start.
Furthermore, we continue to add probes when kprobe_event_gen_cmd_end fails
(and kprobe_event_gen_cmd_start did not fail). In this case the function
even returns successfully when the last call to kprobe_event_gen_cmd_end
is successful.
The behaviour of reporting and aborting after failures is not
consistent.
The function trace_boot_add_kprobe_event now reports each failure and
stops adding probes immediately.
Link: https://lkml.kernel.org/r/20200618163301.25854-1-sascha.ortmann@stud.uni-hannover.de
Cc: stable@vger.kernel.org
Cc: linux-kernel@i4.cs.fau.de
Co-developed-by: Maximilian Werner <maximilian.werner96@gmail.com>
Fixes: da0f1f4167 ("tracing/boottime: Fix kprobe event API usage")
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Maximilian Werner <maximilian.werner96@gmail.com>
Signed-off-by: Sascha Ortmann <sascha.ortmann@stud.uni-hannover.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Linux kernel
============
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