[RFC PATCH v2 0/8] fprobe: Introduce fprobe function entry/exit probe

Masami Hiramatsu
2022-01-12T14:02:57Z

Hi Jiri and Alexei,

Here is the 2nd version of fprobe. This version uses the
ftrace_set_filter_ips() for reducing the registering overhead.
Note that this also drops per-probe point private data, which
is not used anyway.

This introduces the fprobe, the function entry/exit probe with
multiple probe point support. This also introduces the rethook
for hooking function return as same as kretprobe does. This
abstraction will help us to generalize the fgraph tracer,
because we can just switch it from rethook in fprobe, depending
on the kernel configuration.

The patch [1/8] and [7/8] are from your series[1]. Other libbpf
patches will not be affected by this change.

[1] https://lore.kernel.org/all/20220104080943.113249-1-jolsa@kernel.org/T/#u

I also added an out-of-tree (just for testing) patch at the
end of this series ([8/8]) for adding a wildcard support to
the sample program. With that patch, it shows how long the
registration will take;

# time insmod fprobe_example.ko symbol='btrfs_*'
[ 36.130947] fprobe_init: 1028 symbols found
[ 36.177901] fprobe_init: Planted fprobe at btrfs_*
real 0m 0.08s
user 0m 0.00s
sys 0m 0.07s

Thank you,

---

Jiri Olsa (2):
ftrace: Add ftrace_set_filter_ips function
bpf: Add kprobe link for attaching raw kprobes

Masami Hiramatsu (6):
fprobe: Add ftrace based probe APIs
rethook: Add a generic return hook
rethook: x86: Add rethook x86 implementation
fprobe: Add exit_handler support
fprobe: Add sample program for fprobe
[DO NOT MERGE] Out-of-tree: Support wildcard symbol option to sample

arch/x86/Kconfig | 1
arch/x86/kernel/Makefile | 1
arch/x86/kernel/rethook.c | 115 ++++++++++++++++++++
include/linux/bpf_types.h | 1
include/linux/fprobe.h | 57 ++++++++++
include/linux/ftrace.h | 3 +
include/linux/rethook.h | 74 +++++++++++++
include/linux/sched.h | 3 +
include/uapi/linux/bpf.h | 12 ++
kernel/bpf/syscall.c | 195 +++++++++++++++++++++++++++++++++-
kernel/exit.c | 2
kernel/fork.c | 3 +
kernel/kallsyms.c | 1
kernel/trace/Kconfig | 22 ++++
kernel/trace/Makefile | 2
kernel/trace/fprobe.c | 168 +++++++++++++++++++++++++++++
kernel/trace/ftrace.c | 54 ++++++++-
kernel/trace/rethook.c | 226 +++++++++++++++++++++++++++++++++++++++
samples/Kconfig | 7 +
samples/Makefile | 1
samples/fprobe/Makefile | 3 +
samples/fprobe/fprobe_example.c | 154 +++++++++++++++++++++++++++
tools/include/uapi/linux/bpf.h | 12 ++
23 files changed, 1103 insertions(+), 14 deletions(-)
create mode 100644 arch/x86/kernel/rethook.c
create mode 100644 include/linux/fprobe.h
create mode 100644 include/linux/rethook.h
create mode 100644 kernel/trace/fprobe.c
create mode 100644 kernel/trace/rethook.c
create mode 100644 samples/fprobe/Makefile
create mode 100644 samples/fprobe/fprobe_example.c

--
Masami Hiramatsu (Linaro) <mhiramat@kernel.org>