From: Jiri Olsa <olsajiri@gmail.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Deacon <will@kernel.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Mahe Tardy <mahe.tardy@gmail.com>,
Peter Zijlstra <peterz@infradead.org>,
bpf@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, x86@kernel.org,
Yonghong Song <yhs@fb.com>, Song Liu <songliubraving@fb.com>,
Andrii Nakryiko <andrii@kernel.org>,
Mark Rutland <mark.rutland@arm.com>
Subject: Re: [PATCH bpf-next 1/2] arm64/ftrace,bpf: Fix partial regs after bpf_prog_run
Date: Thu, 8 Jan 2026 10:20:16 +0100 [thread overview]
Message-ID: <aV920FGl9-1A1jW7@krava> (raw)
In-Reply-To: <20260107121432.73fccf84@gandalf.local.home>
On Wed, Jan 07, 2026 at 12:14:32PM -0500, Steven Rostedt wrote:
> On Wed, 7 Jan 2026 16:52:52 +0000
> Will Deacon <will@kernel.org> wrote:
>
> > 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:
next prev parent reply other threads:[~2026-01-08 9:20 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-07 9:32 [PATCH bpf-next 1/2] arm64/ftrace,bpf: Fix partial regs after bpf_prog_run Jiri Olsa
2026-01-07 9:32 ` [PATCH bpf-next 2/2] selftests/bpf: Add test for bpf_override_return helper Jiri Olsa
2026-01-07 14:16 ` [PATCH bpf-next 1/2] arm64/ftrace,bpf: Fix partial regs after bpf_prog_run Will Deacon
2026-01-07 16:08 ` Steven Rostedt
2026-01-07 16:52 ` Will Deacon
2026-01-07 17:14 ` Steven Rostedt
2026-01-08 9:20 ` Jiri Olsa [this message]
2026-01-07 16:03 ` Steven Rostedt
2026-01-08 14:32 ` Jiri Olsa
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