Re: [PATCH bpf-next 1/2] arm64/ftrace,bpf: Fix partial regs after bpf_prog_run
From: Jiri Olsa <hidden>
Date: 2026-01-08 09:20:21
Also in:
bpf, linux-trace-kernel
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [security & lsm] (security audit and enforcement using bpf), bpf [tracing], function hooks (ftrace), the rest, tracing · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, KP Singh, Matt Bobrowski, Song Liu, Steven Rostedt, Masami Hiramatsu, Linus Torvalds
On Wed, Jan 07, 2026 at 12:14:32PM -0500, Steven Rostedt wrote:
On Wed, 7 Jan 2026 16:52:52 +0000 Will Deacon [off-list ref] wrote:quoted
diff --git a/include/linux/ftrace_regs.h b/include/linux/ftrace_regs.h index 15627ceea9bc..3ebd8cdac7c6 100644 --- a/include/linux/ftrace_regs.h +++ b/include/linux/ftrace_regs.h@@ -33,6 +33,15 @@ struct ftrace_regs; #define ftrace_regs_get_frame_pointer(fregs) \ frame_pointer(&arch_ftrace_regs(fregs)->regs) +#else + +static __always_inline void +ftrace_partial_regs_update(const struct ftrace_regs *fregs, struct pt_regs *regs) +{ + ftrace_regs_set_instruction_pointer(fregs, instruction_pointer(regs)); + ftrace_regs_set_return_value(fregs, regs_return_value(regs)); +} + #endif /* HAVE_ARCH_FTRACE_REGS */ /* This can be overridden by the architectures */Hmm, maybe that would work. Of course you forgot to add the helper for the !HAVE_ARCH_FTRACE_REGS case ;-)
seems to work, will send new version with that thanks, jirka ---
diff --git a/include/linux/ftrace_regs.h b/include/linux/ftrace_regs.h
index 15627ceea9bc..4b053eb4c9d5 100644
--- a/include/linux/ftrace_regs.h
+++ b/include/linux/ftrace_regs.h@@ -33,6 +33,18 @@ struct ftrace_regs; #define ftrace_regs_get_frame_pointer(fregs) \ frame_pointer(&arch_ftrace_regs(fregs)->regs) +static __always_inline void +ftrace_partial_regs_update(const struct ftrace_regs *fregs, struct pt_regs *regs) { } + +#else + +static __always_inline void +ftrace_partial_regs_update(const struct ftrace_regs *fregs, struct pt_regs *regs) +{ + ftrace_regs_set_instruction_pointer(fregs, instruction_pointer(regs)); + ftrace_regs_set_return_value(fregs, regs_return_value(regs)); +} + #endif /* HAVE_ARCH_FTRACE_REGS */ /* This can be overridden by the architectures */
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 6e076485bf70..3a17f79b20c2 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c@@ -2564,6 +2564,7 @@ kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link, old_run_ctx = bpf_set_run_ctx(&run_ctx.session_ctx.run_ctx); err = bpf_prog_run(link->link.prog, regs); bpf_reset_run_ctx(old_run_ctx); + ftrace_partial_regs_update(fregs, bpf_kprobe_multi_pt_regs_ptr()); rcu_read_unlock(); out: