From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B29CDCCA47B for ; Tue, 5 Jul 2022 19:03:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233156AbiGETDf (ORCPT ); Tue, 5 Jul 2022 15:03:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35450 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233187AbiGETDd (ORCPT ); Tue, 5 Jul 2022 15:03:33 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 836DC13EB3; Tue, 5 Jul 2022 12:03:30 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 13067B8191D; Tue, 5 Jul 2022 19:03:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6B82CC341C7; Tue, 5 Jul 2022 19:03:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1657047807; bh=7lim26PhrH9UscD530EbLXPzArYaPcRW/g+FHGSq21A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AaoGsS7vB1LGM2pNZxWB8UN5LcLVqPPLsl3EAwHq74yH5dQ7yvf/IxrBQEVuE1eHv BwMyQJpZrLbczkqjNYtgx3vyBz1FwrmqGCf+HmwtMHAmq/U5Tps5Oo4NQj8p7FZ5ob dbWt2lty+djASz2LohnH/9HDDt42XRaWG1GZJRODho6OD1s0P8Lo54k2qQZlf66waV sYAVT+5IDko+xbMRG3Kz3XQVD5l5pXjbCgrWBbbC+z7M5Qmwq8KG7Ts7TH4UQz0tae /qxjs+IAple9IgdcNUcfIvJfVnk8J4aTBw3Pfl+ucgidNR7J8FtiodFCWqXr78QeY9 qyINTU3KHZBtg== From: Jiri Olsa To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko Cc: Martynas Pumputis , netdev@vger.kernel.org, bpf@vger.kernel.org, Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Masami Hiramatsu , Yutaro Hayakawa Subject: [PATCH RFC bpf-next 1/4] bpf: Adjust kprobe_multi entry_ip for CONFIG_X86_KERNEL_IBT Date: Tue, 5 Jul 2022 21:03:05 +0200 Message-Id: <20220705190308.1063813-2-jolsa@kernel.org> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20220705190308.1063813-1-jolsa@kernel.org> References: <20220705190308.1063813-1-jolsa@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Martynas reported bpf_get_func_ip returning +4 address when CONFIG_X86_KERNEL_IBT option is enabled. When CONFIG_X86_KERNEL_IBT is enabled we'll have endbr instruction at the function entry, which screws return value of bpf_get_func_ip() helper that should return the function address. There's short term workaround [1] for kprobe_multi bpf program made by Alexei [1], but we need this fixup also for bpf_get_attach_cookie, that returns cookie based on the entry_ip value. Moving the fixup in the fprobe handler, so both bpf_get_func_ip and bpf_get_attach_cookie get expected function address when CONFIG_X86_KERNEL_IBT option is enabled. Keeping the resolved 'addr' in kallsyms_callback, instead of taking ftrace_location value, because we depend on symbol address in the cookie related code. With CONFIG_X86_KERNEL_IBT option the ftrace_location value differs from symbol address. Reported-by: Martynas Pumputis Signed-off-by: Jiri Olsa --- kernel/trace/bpf_trace.c | 3 +++ kernel/trace/ftrace.c | 3 +-- tools/testing/selftests/bpf/progs/kprobe_multi.c | 2 +- 3 files changed, 5 insertions(+), 3 deletions(-) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 4be976cf7d63..ad1e7616c16d 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -2419,6 +2419,9 @@ kprobe_multi_link_handler(struct fprobe *fp, unsigned long entry_ip, { struct bpf_kprobe_multi_link *link; +#ifdef CONFIG_X86_KERNEL_IBT + entry_ip -= ENDBR_INSN_SIZE; +#endif link = container_of(fp, struct bpf_kprobe_multi_link, fp); kprobe_multi_link_prog_run(link, entry_ip, regs); } diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index e750fe141a60..c866855e77e6 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -8033,8 +8033,7 @@ static int kallsyms_callback(void *data, const char *name, if (!bsearch(&name, args->syms, args->cnt, sizeof(*args->syms), symbols_cmp)) return 0; - addr = ftrace_location(addr); - if (!addr) + if (!ftrace_location(addr)) return 0; args->addrs[args->found++] = addr; diff --git a/tools/testing/selftests/bpf/progs/kprobe_multi.c b/tools/testing/selftests/bpf/progs/kprobe_multi.c index 93510f4f0f3a..8c6155e17572 100644 --- a/tools/testing/selftests/bpf/progs/kprobe_multi.c +++ b/tools/testing/selftests/bpf/progs/kprobe_multi.c @@ -44,7 +44,7 @@ static void kprobe_multi_check(void *ctx, bool is_return) return; __u64 cookie = test_cookie ? bpf_get_attach_cookie(ctx) : 0; - __u64 addr = bpf_get_func_ip(ctx) - (CONFIG_X86_KERNEL_IBT ? 4 : 0); + __u64 addr = bpf_get_func_ip(ctx); #define SET(__var, __addr, __cookie) ({ \ if (((const void *) addr == __addr) && \ -- 2.35.3