Hi, Here are the 3rd version for generic kretprobe and kretprobe on x86 for replacing the kretprobe trampoline with rethook. The previous version is here[1] [1] https://lore.kernel.org/all/164821817332.2373735.12048266953420821089.stgit@devnote2/T/#u This version fixed typo and build issues for bpf-next and CONFIG_RETHOOK=y error. I also add temporary mitigation lines for ANNOTATE_NOENDBR macro issue for bpf-next tree [2/4]. #ifndef ANNOTATE_NOENDBR #define ANNOTATE_NOENDBR #endif This will be removed after merging kernel IBT series. Background: This rethook came from Jiri's request of multiple kprobe for bpf[2]. He tried to solve an issue that starting bpf with multiple kprobe will take a long time because bpf-kprobe will wait for RCU grace period for sync rcu events. Jiri wanted to attach a single bpf handler to multiple kprobes and he tried to introduce multiple-probe interface to kprobe. So I asked him to use ftrace and kretprobe-like hook if it is only for the function entry and exit, instead of adding ad-hoc interface to kprobes. For this purpose, I introduced the fprobe (kprobe like interface for ftrace) with the rethook (this is a generic return hook feature for fprobe exit handler)[3]. [2] https://lore.kernel.org/all/20220104080943.113249-1-jolsa@xxxxxxxxxx/T/#u [3] https://lore.kernel.org/all/164191321766.806991.7930388561276940676.stgit@devnote2/T/#u The rethook is basically same as the kretprobe trampoline. I just made it decoupled from kprobes. Eventually, the all arch dependent kretprobe trampolines will be replaced with the rethook trampoline instead of cloning and set HAVE_RETHOOK=y. When I port the rethook for all arch which supports kretprobe, the legacy kretprobe specific code (which is for CONFIG_KRETPROBE_ON_RETHOOK=n) will be removed eventually. Thank you, --- Masami Hiramatsu (3): kprobes: Use rethook for kretprobe if possible x86,rethook,kprobes: Replace kretprobe with rethook on x86 x86,kprobes: Fix optprobe trampoline to generate complete pt_regs Peter Zijlstra (1): x86,rethook: Fix arch_rethook_trampoline() to generate a complete pt_regs arch/Kconfig | 8 ++ arch/x86/Kconfig | 1 arch/x86/include/asm/unwind.h | 23 +++---- arch/x86/kernel/Makefile | 1 arch/x86/kernel/kprobes/common.h | 1 arch/x86/kernel/kprobes/core.c | 106 -------------------------------- arch/x86/kernel/kprobes/opt.c | 25 +++++-- arch/x86/kernel/rethook.c | 127 ++++++++++++++++++++++++++++++++++++++ arch/x86/kernel/unwind_orc.c | 10 +-- include/linux/kprobes.h | 51 +++++++++++++++ kernel/Makefile | 1 kernel/kprobes.c | 124 +++++++++++++++++++++++++++++++------ kernel/trace/trace_kprobe.c | 4 + 13 files changed, 325 insertions(+), 157 deletions(-) create mode 100644 arch/x86/kernel/rethook.c -- Masami Hiramatsu (Linaro) <mhiramat@xxxxxxxxxx>
