From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ej1-f50.google.com (mail-ej1-f50.google.com [209.85.218.50]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D72491F4C85; Wed, 3 Sep 2025 06:35:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.218.50 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756881359; cv=none; b=ShQhaDae+QzJBWPuQmUDGG/diW4Pzn4QxZkxxfxuuEpMGjfeSWyZqs28FWIcSyhJ95iVdIsqwsWCVqz0HAT+kHe4Bu/UIs8ZZX7Fs0T5uZZOTgFJ5xrg/uB/wLDAl6VRDty/zbhomh1fCN7oxarT9qFoSKgXR4ivdlKoj6g5qs4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756881359; c=relaxed/simple; bh=UTMzuQVzloVO/bJU0/VxUNPURnzSJf47Kqe1+UJzVyM=; h=From:Date:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=VbtrsqO+iBalqWixkoNnPM1p+/dqv2E3MENJm6fa5IB5VNPNbhZySiJ6AyQxo7oYTVfUAI87RdAGbDcNbA4CDmhZsFpFpwaE5zrNHDPSc3RBYPG1GpsttAgyqAJNhm6SPvTbKItomyLE2rKR2y2GSSl+YaZBPFMTgeqkEwXKVOI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=ab7lWTdA; arc=none smtp.client-ip=209.85.218.50 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="ab7lWTdA" Received: by mail-ej1-f50.google.com with SMTP id a640c23a62f3a-b02c719a117so460521066b.1; Tue, 02 Sep 2025 23:35:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1756881356; x=1757486156; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:date:from:from:to:cc:subject:date:message-id:reply-to; bh=kFyoMJw6KiFQC6JDcSTadI7EhSdz+gbovd/Nmw8VGsI=; b=ab7lWTdA7SNDmxFE9ZXzkNhvk73IlbqBgs1gZqhr9xaqWu5buoJnc9D/05aTJjA4JK r/fMNnhqkItyo3WRyeZQe1TNDXbKyvhaRr8sdunHnu/1njeV1EL1ysdRcg/Wt4MZSASC jnqM9CFDXSOjkHYR/opYd7hazI3LUm8iK2LTwvuzh8v+5rN1Y+7i3k7bXSxwa4oqP4BB lFojdDWxlC1vHCVQHu+mp03MEkDX35zgJv5C3J6QCYlVwIduFCBoufGaZFTm/ogGr/IB Pg3wNVcpif7Ar90Pkqmpi4v30zRX2jpPjqvCr+3Nbgs9+EAHE6tYLHv4jKFoD/L+PwDZ U30g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1756881356; x=1757486156; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:date:from:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=kFyoMJw6KiFQC6JDcSTadI7EhSdz+gbovd/Nmw8VGsI=; b=PFGf+O0KEgFvJ6/8ZUDMNKrkWmruBh7RtNu28vAl8Yg2iaoxg1IHoO/91KXgxsaT4q vbVzHc+jurBQErE7ADkcQMyYyIUUcZ8vjdwOQSO5EjGimHhcy1wcEKn2tX7goOk2k13u j5N/IKyFMx982vjXAfQG19SlP+1hVzWm5fsc1IF+0Thibmb+GYw5ilp4ZBkOlNHIfdkr 72pBLeP7SwB+Q4XraJJBJ2S3HHCPOKZn2Zh01hO/i7FWyfgvTfDUPuzMLZfb96Mu5Ns6 8pUtW4CCaKaAaiqFkMSbAvk6PBaslz3YPA154xKEcasxdORF5xwLXXVtNxl9qV8I2uKQ gdrw== X-Forwarded-Encrypted: i=1; AJvYcCUQHngj7Fe+mOS7LL8jow3gYsz3zqgiimXDcLVJQwdh7r5SF63VfBjRjf22jwsYp4bL52V2cpC15hKkEBgN@vger.kernel.org, AJvYcCWE0XhmeTaLMJioC4XLbY35eQv9sNNVwjRFy+3biVwC9OT3mpVjqk0UQvbVD8128zEQw/E=@vger.kernel.org, AJvYcCXzuusa2p4lWanYGRem+5v0cJOsWc5UaxVQ8JxXfuvMqT8xeMnMzL/lmcTf/x2nW9UjAodwBAJkTtDurVo07mUMGvHe@vger.kernel.org X-Gm-Message-State: AOJu0YwJQ5JhoxblNDdrpGZ1H/aSnOlxISpVgQESHwMiDwdjq5eYSzUR VpsnA0MXkqhnvf8MlYHzFoNIa6Zoxxy4btOm7NeY27OluNfFx3kMuC12 X-Gm-Gg: ASbGncsFdnhKqDJxhCmn+t0TVTOBvwvnIL65vmBccdWkC3QXS2dTfliGSKyfvxohvsr 3YOSRgQJa47Cj/opDmgMJiwSMbfvCHITynNlmLVL1W5QA8hOEwkeX69nTtKX0/iv+R3vfATtb9V M9Mf9fNgV5uo57Tfg6K45kkxCGAqEiloZubFeO7SAdEOMPMDiBFz28D/w/KUBTFJk6+LEi+N/lr om9EV8uKjnLSE0IRe3u9G2kcKun/4Q1WnahkBwMz3whVynObCiI0ltCJKZfdw/vp4S08gVsywZL TTA64QjN9676GWPw7iPjFsuuQMC86HVquXmjiXJNgSazRRaJ4Mzby4043KezYS7vhzs6KGDcc2x rpTaUExoEft4= X-Google-Smtp-Source: AGHT+IGXl/QxdYQv+E32uj2HADurAuKBG3IRZKyIzyk6ED5cmYez/6lQZIkLkkOKPemVqFpwMRKLYw== X-Received: by 2002:a17:906:f596:b0:b04:65b4:707 with SMTP id a640c23a62f3a-b0465b40b24mr169370466b.13.1756881356006; Tue, 02 Sep 2025 23:35:56 -0700 (PDT) Received: from krava ([176.74.159.170]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-b04190700a4sm838121166b.63.2025.09.02.23.35.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 02 Sep 2025 23:35:55 -0700 (PDT) From: Jiri Olsa X-Google-Original-From: Jiri Olsa Date: Wed, 3 Sep 2025 08:35:53 +0200 To: Masami Hiramatsu Cc: Oleg Nesterov , Peter Zijlstra , Andrii Nakryiko , bpf@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, x86@kernel.org, Song Liu , Yonghong Song , John Fastabend , Hao Luo , Steven Rostedt , Ingo Molnar Subject: Re: [PATCH perf/core 01/11] uprobes: Add unique flag to uprobe consumer Message-ID: References: <20250902143504.1224726-1-jolsa@kernel.org> <20250902143504.1224726-2-jolsa@kernel.org> <20250903001133.8a02cf5db5ab4fd23c9a334f@kernel.org> 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=us-ascii Content-Disposition: inline In-Reply-To: <20250903001133.8a02cf5db5ab4fd23c9a334f@kernel.org> On Wed, Sep 03, 2025 at 12:11:33AM +0900, Masami Hiramatsu wrote: > On Tue, 2 Sep 2025 16:34:54 +0200 > Jiri Olsa wrote: > > > Adding unique flag to uprobe consumer to ensure it's the only consumer > > attached on the uprobe. > > > > This is helpful for use cases when consumer wants to change user space > > registers, which might confuse other consumers. With this change we can > > ensure there's only one consumer on specific uprobe. > > nit: Does this mean one callback (consumer) is exclusively attached? > If so, "exclusive" will be better wording? yes, exclusive is better, will change thanks, jirka > > The logic looks good to me. > > Thanks, > > > > > Signed-off-by: Jiri Olsa > > --- > > include/linux/uprobes.h | 1 + > > kernel/events/uprobes.c | 30 ++++++++++++++++++++++++++++-- > > 2 files changed, 29 insertions(+), 2 deletions(-) > > > > diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h > > index 08ef78439d0d..0df849dee720 100644 > > --- a/include/linux/uprobes.h > > +++ b/include/linux/uprobes.h > > @@ -60,6 +60,7 @@ struct uprobe_consumer { > > struct list_head cons_node; > > > > __u64 id; /* set when uprobe_consumer is registered */ > > + bool is_unique; /* the only consumer on uprobe */ > > }; > > > > #ifdef CONFIG_UPROBES > > diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c > > index 996a81080d56..b9b088f7333a 100644 > > --- a/kernel/events/uprobes.c > > +++ b/kernel/events/uprobes.c > > @@ -1024,14 +1024,35 @@ static struct uprobe *alloc_uprobe(struct inode *inode, loff_t offset, > > return uprobe; > > } > > > > -static void consumer_add(struct uprobe *uprobe, struct uprobe_consumer *uc) > > +static bool consumer_can_add(struct list_head *head, struct uprobe_consumer *uc) > > +{ > > + /* Uprobe has no consumer, we can add any. */ > > + if (list_empty(head)) > > + return true; > > + /* Uprobe has consumer/s, we can't add unique one. */ > > + if (uc->is_unique) > > + return false; > > + /* > > + * Uprobe has consumer/s, we can add nother consumer only if the > > + * current consumer is not unique. > > + **/ > > + return !list_first_entry(head, struct uprobe_consumer, cons_node)->is_unique; > > +} > > + > > +static int consumer_add(struct uprobe *uprobe, struct uprobe_consumer *uc) > > { > > static atomic64_t id; > > + int ret = -EBUSY; > > > > down_write(&uprobe->consumer_rwsem); > > + if (!consumer_can_add(&uprobe->consumers, uc)) > > + goto unlock; > > list_add_rcu(&uc->cons_node, &uprobe->consumers); > > uc->id = (__u64) atomic64_inc_return(&id); > > + ret = 0; > > +unlock: > > up_write(&uprobe->consumer_rwsem); > > + return ret; > > } > > > > /* > > @@ -1420,7 +1441,12 @@ struct uprobe *uprobe_register(struct inode *inode, > > return uprobe; > > > > down_write(&uprobe->register_rwsem); > > - consumer_add(uprobe, uc); > > + ret = consumer_add(uprobe, uc); > > + if (ret) { > > + put_uprobe(uprobe); > > + up_write(&uprobe->register_rwsem); > > + return ERR_PTR(ret); > > + } > > ret = register_for_each_vma(uprobe, uc); > > up_write(&uprobe->register_rwsem); > > > > -- > > 2.51.0 > > > > > -- > Masami Hiramatsu (Google)