From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 560E93C0611; Thu, 21 May 2026 12:45:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779367506; cv=none; b=O8/e1ERlmASznE3DX2PeVekSQubdpPafbCaHGneUmoEDVasidwDYBlOuDKuOhKzSEibc5raxPy1Vietqxvgh2zO/Z+C7WpxOEWKl5lrMsO0M/FrJlI6M5XaZefrOy74XOkFjlYOedatnA4oBB4HDvfIBRsbZfu6aSqjJo9c3E4U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779367506; c=relaxed/simple; bh=CgmBHgIl/8KarisqcIjoXQUs9GiUp7k2HyaBfDa/g74=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=dSrzkjbqW7zKjB66zSpusRjj60B8FAHm9P+IIQYSN/VVW8VSIe42e4ArEKFTxLoT4bEalHQ/hE3U17tpGurAR/OCko1WprpXWkEXULEZj6h9lgQ1wC9e+3ihsUSZndTQgvpTTrOy6NlhU5fMcc+6ZXymuoq+yI/TLrl65AwV6ew= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=S7Irf7rf; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="S7Irf7rf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5B3CA1F000E9; Thu, 21 May 2026 12:45:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779367505; bh=fGNN99krwRo4X3DARnJ0BHyRyqXrYK+3zf8N7M3UH2U=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=S7Irf7rf42SjQTzeVXq/uJMU5a9oFT0RiLawRZVvbBUqjp+gBMApWqFeANow7EX9i WxWoSG4IbKa3AB/DJUD6noPqgm7lLOznSCxwY3NqVHPo+LChWvILzupsG+eX5nXROg tcIhQJlciyP9+dnJDaNvce7zjLHE3md40bI1YPachS/5bp5oj90h8kCiaNXEr2XLGM z5fYxf9W50e74HE9gPnnHfb/wZA2uTO458iJikJ41SHE+rndNH6FsHCkWMFECv21jE iFW614hfvq47Xrx0ffZld/UWvyA1I3elqzpl7EPBW9yvKegRwwApZyV2M4NdUS+PBq RVosC1HatGIKw== 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: [PATCHv3 05/12] libbpf: Change has_nop_combo to work on top of nop10 Date: Thu, 21 May 2026 14:44:04 +0200 Message-ID: <20260521124411.31133-6-jolsa@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260521124411.31133-1-jolsa@kernel.org> References: <20260521124411.31133-1-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..484a4354e82b 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, 0x2e, 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