From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 EC4F7221F0B for ; Fri, 4 Apr 2025 20:04:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743797083; cv=none; b=sFTiTR52eOZVd5cr1TnSsCJRUERKxWphGD8cS73n63nkQpORocUFxhK1aYMasmpdkp8DNQC6jvOqzchfN4H3UpAq93gZqSD3rWNf3XN/TYGO8coqHKfVQyK5CUYG5HycqXAUaPzQh5+hfP2eU44m2Bt8uJns6NNyzPwAo9DSQ/o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743797083; c=relaxed/simple; bh=IvhhTUIiW/q5zcRrtTNnMYdCLxAmDvUAWeXeyHuVrZk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=cZ15V9J8uz2XE0aiazcN6L6CuUlps7sV60xidLqtfFf43mJJ717gHCyaLIlQYuFWk0uNbW36LKiF/+uinpooHMtsbUWv4KvZiKLUyjvj2rBTFHdVfobAiIcySRwhOw5NyX3FcImQCZK73br218DVRVpMUZv539TtbfMeqGwV4w8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=A2A4MqAs; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="A2A4MqAs" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1743797080; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=IvhhTUIiW/q5zcRrtTNnMYdCLxAmDvUAWeXeyHuVrZk=; b=A2A4MqAstFjlSFzcHGXAAuCeOE6uQ49awr7+LhjOIQ9l+6+jmmkNC34wCicl9w6Piv+fKK 4Y5QuY6/WdHkMGcRx984dfQh5YrPQfuNEVuzXnulGEkEuLbx7POwyK0QxI/qeBMGjTuM3C tfvdEamEAjitsfXe6eY+wT7LpCJBx1M= Received: from mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-591-_AB5LUwCNciRrLpL4MbUMw-1; Fri, 04 Apr 2025 16:04:34 -0400 X-MC-Unique: _AB5LUwCNciRrLpL4MbUMw-1 X-Mimecast-MFC-AGG-ID: _AB5LUwCNciRrLpL4MbUMw_1743797072 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 504C819560B8; Fri, 4 Apr 2025 20:04:32 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.45.224.144]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with SMTP id 1B9D71809B74; Fri, 4 Apr 2025 20:04:27 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Fri, 4 Apr 2025 22:03:57 +0200 (CEST) Date: Fri, 4 Apr 2025 22:03:52 +0200 From: Oleg Nesterov To: Andrii Nakryiko Cc: linux-trace-kernel@vger.kernel.org, peterz@infradead.org, mingo@kernel.org, bpf@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@meta.com, rostedt@goodmis.org, mhiramat@kernel.org, bigeasy@linutronix.de, ast@kernel.org Subject: Re: [PATCH v2 tip/perf] uprobes: avoid false lockdep splat in uprobe timer callback Message-ID: <20250404200351.GI3720@redhat.com> References: <20250404194848.2109539-1-andrii@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: <20250404194848.2109539-1-andrii@kernel.org> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 On 04/04, Andrii Nakryiko wrote: > > Also, point out in the comments more explicitly why we use seqcount > despite our reader side being rather simple and never retrying. We favor > well-maintained kernel primitive in favor of open-coding our own memory > barriers. > > Link: https://lore.kernel.org/bpf/CAADnVQLLOHZmPO4X_dQ+cTaSDvzdWHzA0qUqQDhLFYL3D6xPxg@mail.gmail.com/ > Reported-by: Alexei Starovoitov > Suggested-by: Sebastian Siewior > Fixes: 8622e45b5da1 ("uprobes: Reuse return_instances between multiple uretprobes within task") > Signed-off-by: Andrii Nakryiko LGTM. FWIW, Acked-by: Oleg Nesterov