On Mon, Oct 18, 2021 at 4:07 PM FMDF <fmdefrancesco@gmail.com> wrote:
On Mon, 18 Oct 2021, 04:46 Dongliang Mu, <mudongliangabcd@gmail.com> wrote:
Hi all,
I am writing to kindly ask one question: is there any tracing mechanism in Linux kernel that can trace all the executed instructions of a user process? If this user process is run on different processors, traces of this process on different processors should be also recorded.
You've not explained in detail what is the purpose of the tracing that you want to do. Missing this information I can only provide you a list of links to various tools and methods. Take a look by yourself and try to figure out what is better suited for your needs...
I want to log all the executed instructions of a user process (e.g., poc.c in syzkaller) in the kernel mode and then would like to leverage backward analysis to capture the root cause of kernel panic/crash. Therefore, I need the instruction-level tracing mechanisms or tools.
https://lwn.net/Kernel/Index/#Development_tools-Kernel_tracing trace-cmd: https://trace-cmd.org
Ftrace is working at the function level. Therefore, ftrace and tracers based on ftrace are not suitable for my scenario.
perf ftrace: <Linux source>/tools/perf/Documentation/perf-trace.txt perf-tools: https://github.com/brendangregg/perf-tools
I am not familiar with the perf tool and cannot verify if it works for my scenario.
In particular, the "function_graph" tracer of ftrace seems to be suited for your purposes:
https://man7.org/linux/man-pages/man1/trace-cmd.1.html https://man7.org/linux/man-pages/man1/trace-cmd-record.1.html https://man7.org/linux/man-pages/man1/trace-cmd-report.1.html
Obviously, gdb (and friends) is still invaluable (but it may be difficult to use, depending on your knowledge and experience, so use it if you really know that you need it):
https://www.kernel.org/doc/html/latest/dev-tools/gdb-kernel-debugging.html https://www.kernel.org/doc/html/latest/dev-tools/kgdb.html
Regards,
Fabio M. De Francesco
Any comment is welcome.
-- My best regards to you.
No System Is Safe! Dongliang Mu
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