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 E972A221F20; Mon, 13 Oct 2025 14:51:35 +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=1760367096; cv=none; b=awq70MTsJJ5/GFCo1oIWZEU1m16OgJPAckruWaSeqLGC8/2Xul4AslJlPvS3yWnDCPMyfgkQKQ7mSyS1tFMgcEqkQFHtt10BLalqmpB/vdUfLCw6B2oEwX6SxDhwrykXg9+Z4hFqAeqnC8mvSNtJOtBLr9wPSYgUcNlSUz3RnaM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760367096; c=relaxed/simple; bh=1Wam95m/XtbYPq1mhpZzXjcgw0UyZj9CZEfnY2AjPZM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Bw5cf286FJzt5n0kLo+8Oka1sBNs9f72bhLiXc3XzW31y1eI17onBAnoOcmNpWQ+u2QqzerleYtjNJ6mgUqt1wmG42wwbY0w42tkTZoNV/zrKOgOEcDNT4PywdgA7IcEKtwIMVZJAbhqrnrLX2VNCQrUAXRnAbtOMaToJ9CWCsk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=EVl/rR1w; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="EVl/rR1w" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1D6DEC4CEE7; Mon, 13 Oct 2025 14:51:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1760367095; bh=1Wam95m/XtbYPq1mhpZzXjcgw0UyZj9CZEfnY2AjPZM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EVl/rR1wg8dAavqkCJyqdOQE9ju/U7Hrj3iNeurfY5cnQ9d19VfPAL6X9NwT64tbQ 2x7+rWgAqHDm0gLYTxwzAKjhSOiLXB0ReEC7rfrhmEH9h4MFooCAVC2d0/edx12EcT QDMOIbTdxni2AsN6CBeRbkzmsJySVOp3G2NhONo4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Tao Chen , Andrii Nakryiko , Sasha Levin Subject: [PATCH 6.1 057/196] bpf: Remove migrate_disable in kprobe_multi_link_prog_run Date: Mon, 13 Oct 2025 16:43:50 +0200 Message-ID: <20251013144316.646626696@linuxfoundation.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251013144314.549284796@linuxfoundation.org> References: <20251013144314.549284796@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tao Chen [ Upstream commit abdaf49be5424db74e19d167c10d7dad79a0efc2 ] Graph tracer framework ensures we won't migrate, kprobe_multi_link_prog_run called all the way from graph tracer, which disables preemption in function_graph_enter_regs, as Jiri and Yonghong suggested, there is no need to use migrate_disable. As a result, some overhead may will be reduced. And add cant_sleep check for __this_cpu_inc_return. Fixes: 0dcac2725406 ("bpf: Add multi kprobe link") Signed-off-by: Tao Chen Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20250814121430.2347454-1-chen.dylane@linux.dev Signed-off-by: Sasha Levin --- kernel/trace/bpf_trace.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 243122ca56793..e6fde598f7629 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -2636,18 +2636,23 @@ kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link, struct bpf_run_ctx *old_run_ctx; int err; + /* + * graph tracer framework ensures we won't migrate, so there is no need + * to use migrate_disable for bpf_prog_run again. The check here just for + * __this_cpu_inc_return. + */ + cant_sleep(); + if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) { err = 0; goto out; } - migrate_disable(); rcu_read_lock(); 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); rcu_read_unlock(); - migrate_enable(); out: __this_cpu_dec(bpf_prog_active); -- 2.51.0