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 C9E1F3F20E0; Mon, 18 May 2026 11:00:41 +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=1779102041; cv=none; b=LqiPmmMKbaoor6uebZy0kLgCjJV827+XLvLMY9eyZfIQffYHMVEYYbHTy9HhChRuN4/NtkfXbQTLrq785WPknGN+DqjooD52eQ5x7H6lBc421DV4rg2uJQcUF7TrNR0O471+UdF7SOqfl1s17Kbjyn9fb57lGg20J9Bd8PZYusw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779102041; c=relaxed/simple; bh=jkZjaMeB7hY2buD7BZ6cwVYXocVJBpBFvl4YSwI5dQ4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=QrAPZBLtQWgik0IgVD5+ev9QWuYBYrKmVRq8VRfpjKNSs6HgRRlHAbjlqVWMsPIcKNkT4R4rCmYj5qRqITlWO4RUIKQ1Qlol637cA/95vgSQW4q5pmQ3JzQRDlrBC0YKPzhtSvdjsZ3PgEyCsme7RE2KMyhps2WQpV2andDKDaA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=M8i7Z0b5; 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="M8i7Z0b5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 91BA7C2BCB7; Mon, 18 May 2026 11:00:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1779102040; bh=jkZjaMeB7hY2buD7BZ6cwVYXocVJBpBFvl4YSwI5dQ4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=M8i7Z0b58v/tUtvMY2ND0IdeFYj9gtqZ8yqQ6t81KN96cw+pY5bqa2egM8ym39P1g OGeCgeuQp/tGl4s122El7pC/OIXdIpbKwyAAHxQKAc5hTVV3OEsBoT86P4uN6LL/KL p8uubCmTBGrAGqQiJvhFiZPRfVxD/s2BdN8PZLzvc7ZRlIuM/JvV7wdKJFsPtOpFHz vkX7ba9mj0Ra8VyaotadIqh6xXmJoLG5rTu6V3IsJXx7SCIAGefkCD9meuv+7GkmFD uqyskykDeOWwSS80uWf+p3yqm4NpXrQ/WCegdnlyzH53OG6cYnzt13GX7+KzVKggkW 33a0TOGa1aRDQ== From: Jiri Olsa To: Oleg Nesterov , Peter Zijlstra , Ingo Molnar , Masami Hiramatsu , Andrii Nakryiko Cc: Jakub Sitnicki , bpf@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: [PATCHv2 04/11] libbpf: Change has_nop_combo to work on top of nop10 Date: Mon, 18 May 2026 12:59:50 +0200 Message-ID: <20260518105957.123445-5-jolsa@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260518105957.123445-1-jolsa@kernel.org> References: <20260518105957.123445-1-jolsa@kernel.org> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit We now expect nop combo with 10 bytes nop instead of 5 bytes nop, fixing has_nop_combo to reflect that. Fixes: 41a5c7df4466 ("libbpf: Add support to detect nop,nop5 instructions combo for usdt probe") Reviewed-by: Jakub Sitnicki Signed-off-by: Jiri Olsa --- tools/lib/bpf/usdt.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/tools/lib/bpf/usdt.c b/tools/lib/bpf/usdt.c index e3710933fd52..7e62e4d5bedd 100644 --- a/tools/lib/bpf/usdt.c +++ b/tools/lib/bpf/usdt.c @@ -305,7 +305,7 @@ struct usdt_manager *usdt_manager_new(struct bpf_object *obj) /* * Detect kernel support for uprobe() syscall, it's presence means we can - * take advantage of faster nop5 uprobe handling. + * take advantage of faster nop10 uprobe handling. * Added in: 56101b69c919 ("uprobes/x86: Add uprobe syscall to speed up uprobe") */ man->has_uprobe_syscall = kernel_supports(obj, FEAT_UPROBE_SYSCALL); @@ -596,14 +596,14 @@ static int parse_usdt_spec(struct usdt_spec *spec, const struct usdt_note *note, #if defined(__x86_64__) static bool has_nop_combo(int fd, long off) { - unsigned char nop_combo[6] = { - 0x90, 0x0f, 0x1f, 0x44, 0x00, 0x00 /* nop,nop5 */ + unsigned char nop_combo[11] = { + 0x90, 0x66, 0x66, 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00, }; - unsigned char buf[6]; + unsigned char buf[11]; - if (pread(fd, buf, 6, off) != 6) + if (pread(fd, buf, 11, off) != 11) return false; - return memcmp(buf, nop_combo, 6) == 0; + return memcmp(buf, nop_combo, 11) == 0; } #else static bool has_nop_combo(int fd, long off) @@ -814,8 +814,8 @@ static int collect_usdt_targets(struct usdt_manager *man, struct elf_fd *elf_fd, memset(target, 0, sizeof(*target)); /* - * We have uprobe syscall and usdt with nop,nop5 instructions combo, - * so we can place the uprobe directly on nop5 (+1) and get this probe + * We have uprobe syscall and usdt with nop,nop10 instructions combo, + * so we can place the uprobe directly on nop10 (+1) and get this probe * optimized. */ if (man->has_uprobe_syscall && has_nop_combo(elf_fd->fd, usdt_rel_ip)) { -- 2.53.0