Messages in this thread | | | Date | Thu, 29 Feb 2024 16:13:20 +0900 | From | Masami Hiramatsu (Google) <> | Subject | Re: [PATCH v2 0/7] tracing/probes: Support function parameter access from return probe |
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On Thu, 29 Feb 2024 15:38:55 +0900 Masami Hiramatsu (Google) <mhiramat@kernel.org> wrote:
> Hmm, this seems arch_rethook_trampoline caused the issue. > > And curiously, it depends on the number of stored data. > > OK: > /sys/kernel/tracing # echo 'f vfs_read%return $arg1 $arg2 $arg3' >> dynamic_events > /sys/kernel/tracing # echo 1 > events/fprobes/enable > > NG: > /sys/kernel/tracing # echo 'f vfs_read%return $arg1 $arg2 $arg3 $arg4' >> dynamic_events > /sys/kernel/tracing # echo 1 > events/fprobes/enable > > I also confirmed that on 'vfs_write' caused the same result. 3 arguments(24 bytes) is OK, > but 4 arguments (32bytes) is NG.
And this may be the fprobe bug. kretprobe events doesn't show this issue.
OK: /sys/kernel/tracing # echo 'r vfs_read $arg*' >> kprobe_events /sys/kernel/tracing # echo 1 > events/kprobes/enable
But this is strange because both uses same rethook...
Thank you,
-- Masami Hiramatsu (Google) <mhiramat@kernel.org>
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