From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 79014745C5; Mon, 29 Apr 2024 14:57:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714402641; cv=none; b=OtFiXc9MHab4IdbSfSwcrMeM12cIGv7EX6ixjfFo+KDpukTYuLsoQTEp3zRVW+R+ta92K4IgzuJida9IV5PrpszcHfTUluXrEBLaOW2Uw31onJRN85KPX29k0/EKl8AkTU5rZXI1Fk+qaeIrqF5gyTNfjsSv0ClP6Zrdi0pRhlk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714402641; c=relaxed/simple; bh=hWivQfQuF0fT04SNK+ienLT/ACa8KyiRA5sWZVweDL0=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=toco0n/mVdCQ8J7dD6upI4zaY1sMHhf5yDD8uezJ4oiHDCnMzsGUQkjNp8YHnThexxiQnud9uMJG1wwqRrLUdEAZ9aSlAdvKHyedmuxPY3S398UVtw1MdmzCFBkT50LcYyXN/8PYVAZWPRqGxVh63ObAO/r7hS2lIRszjlbNtFk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=knUO9XcY; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="knUO9XcY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 05D58C113CD; Mon, 29 Apr 2024 14:57:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1714402641; bh=hWivQfQuF0fT04SNK+ienLT/ACa8KyiRA5sWZVweDL0=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=knUO9XcY4eGnQctWABveJeL0qRZmdybzZ834JWlQaEIXJ+2ElpTriIqFU9x5Y8R+d 30zsFdVFpC4mqRED4c3tkyQISWeOWgX42OSKkPZGlHoDtu82gNa8SxpmuG7hjYxC6t Cz/k3L5UAFdloPiRpd1r+EoaRLG8emYBjiS012e5+6L2M0ud1O4cy7IdpOP5a8e924 10PdGhurGmH83ffIg5bJjYJUK3cgGllmHWeAQ6447ejo+RSme6Zfmi+fIwME8ulx1W OkcHGTFolS8rdOrRkHO5Gam0a+nganFmdEwPoJ8QML7UH5TzD5kte9J1B3l6oCBeTd 54Sz03oE8dqoQ== Date: Mon, 29 Apr 2024 23:57:14 +0900 From: Masami Hiramatsu (Google) To: Andrii Nakryiko Cc: Alexei Starovoitov , Steven Rostedt , Florent Revest , linux-trace-kernel@vger.kernel.org, LKML , Martin KaFai Lau , bpf , Sven Schnelle , Alexei Starovoitov , Jiri Olsa , Arnaldo Carvalho de Melo , Daniel Borkmann , Alan Maguire , Mark Rutland , Peter Zijlstra , Thomas Gleixner , Guo Ren Subject: Re: [PATCH v9 29/36] bpf: Enable kprobe_multi feature if CONFIG_FPROBE is enabled Message-Id: <20240429235714.54135bc2d6dfcf4d0e338c46@kernel.org> In-Reply-To: References: <171318533841.254850.15841395205784342850.stgit@devnote2> <171318568081.254850.16193015880509111721.stgit@devnote2> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On Thu, 25 Apr 2024 13:09:32 -0700 Andrii Nakryiko wrote: > On Mon, Apr 15, 2024 at 6:22 AM Masami Hiramatsu (Google) > wrote: > > > > From: Masami Hiramatsu (Google) > > > > Enable kprobe_multi feature if CONFIG_FPROBE is enabled. The pt_regs is > > converted from ftrace_regs by ftrace_partial_regs(), thus some registers > > may always returns 0. But it should be enough for function entry (access > > arguments) and exit (access return value). > > > > Signed-off-by: Masami Hiramatsu (Google) > > Acked-by: Florent Revest > > --- > > Changes from previous series: NOTHING, Update against the new series. > > --- > > kernel/trace/bpf_trace.c | 22 +++++++++------------- > > 1 file changed, 9 insertions(+), 13 deletions(-) > > > > diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c > > index e51a6ef87167..57b1174030c9 100644 > > --- a/kernel/trace/bpf_trace.c > > +++ b/kernel/trace/bpf_trace.c > > @@ -2577,7 +2577,7 @@ static int __init bpf_event_init(void) > > fs_initcall(bpf_event_init); > > #endif /* CONFIG_MODULES */ > > > > -#if defined(CONFIG_FPROBE) && defined(CONFIG_DYNAMIC_FTRACE_WITH_REGS) > > +#ifdef CONFIG_FPROBE > > struct bpf_kprobe_multi_link { > > struct bpf_link link; > > struct fprobe fp; > > @@ -2600,6 +2600,8 @@ struct user_syms { > > char *buf; > > }; > > > > +static DEFINE_PER_CPU(struct pt_regs, bpf_kprobe_multi_pt_regs); > > this is a waste if CONFIG_HAVE_PT_REGS_TO_FTRACE_REGS_CAST=y, right? > Can we guard it? Good catch! Yes, we can guard it. > > > > + > > static int copy_user_syms(struct user_syms *us, unsigned long __user *usyms, u32 cnt) > > { > > unsigned long __user usymbol; > > @@ -2792,13 +2794,14 @@ static u64 bpf_kprobe_multi_entry_ip(struct bpf_run_ctx *ctx) > > > > static int > > kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link, > > - unsigned long entry_ip, struct pt_regs *regs) > > + unsigned long entry_ip, struct ftrace_regs *fregs) > > { > > struct bpf_kprobe_multi_run_ctx run_ctx = { > > .link = link, > > .entry_ip = entry_ip, > > }; > > struct bpf_run_ctx *old_run_ctx; > > + struct pt_regs *regs; > > int err; > > > > if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) { > > @@ -2809,6 +2812,7 @@ kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link, > > > > migrate_disable(); > > rcu_read_lock(); > > + regs = ftrace_partial_regs(fregs, this_cpu_ptr(&bpf_kprobe_multi_pt_regs)); > > and then pass NULL if defined(CONFIG_HAVE_PT_REGS_TO_FTRACE_REGS_CAST)? Indeed. Thank you! > > > > old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx); > > err = bpf_prog_run(link->link.prog, regs); > > bpf_reset_run_ctx(old_run_ctx); > > @@ -2826,13 +2830,9 @@ kprobe_multi_link_handler(struct fprobe *fp, unsigned long fentry_ip, > > void *data) > > { > > struct bpf_kprobe_multi_link *link; > > - struct pt_regs *regs = ftrace_get_regs(fregs); > > - > > - if (!regs) > > - return 0; > > > > link = container_of(fp, struct bpf_kprobe_multi_link, fp); > > - kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs); > > + kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), fregs); > > return 0; > > } > > > > @@ -2842,13 +2842,9 @@ kprobe_multi_link_exit_handler(struct fprobe *fp, unsigned long fentry_ip, > > void *data) > > { > > struct bpf_kprobe_multi_link *link; > > - struct pt_regs *regs = ftrace_get_regs(fregs); > > - > > - if (!regs) > > - return; > > > > link = container_of(fp, struct bpf_kprobe_multi_link, fp); > > - kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs); > > + kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), fregs); > > } > > > > static int symbols_cmp_r(const void *a, const void *b, const void *priv) > > @@ -3107,7 +3103,7 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr > > kvfree(cookies); > > return err; > > } > > -#else /* !CONFIG_FPROBE || !CONFIG_DYNAMIC_FTRACE_WITH_REGS */ > > +#else /* !CONFIG_FPROBE */ > > int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) > > { > > return -EOPNOTSUPP; > > > > -- Masami Hiramatsu (Google)