From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) (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 101AA200127; Thu, 19 Jun 2025 08:49:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=216.40.44.10 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750322996; cv=none; b=q2bFzre3ECxVUdDm2yEunxhm7tShvuBEf5e66WVBV9yl+hBnNv/aNbwq5p3HIYpaPl3hG4gZYpZImggtUGUiDAEp+SjFhbrO4J2kjvlRCYOxNqlzxdDtoYfeQa9Z5zdIg484zgzJLIfMzu/zMqZpzhzmsdmjnrcjt6GT6jlQ8DI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750322996; c=relaxed/simple; bh=n71zzM0zn0yiB0UuLeFSmpaT+ZOUy5bd8NLW3zJzq+g=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=HVCApn2+23JKakkp6StPIZnQ1xst0Bk0fkAM9InBTuuXtVxsjKOkAJr0X3OHlTT4VZCHtMresB6pyZpw3s3NDLZi1USz3S2A36frHggYz0u5aGJmNdu3YDzwv+K1mo0zdAuaz3cfr3yHOqo7RC5guLpC2bONcv2aDunPq8ouUP4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org; spf=pass smtp.mailfrom=goodmis.org; arc=none smtp.client-ip=216.40.44.10 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=goodmis.org Received: from omf06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 688035B3C3; Thu, 19 Jun 2025 08:49:52 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: rostedt@goodmis.org) by omf06.hostedemail.com (Postfix) with ESMTPA id 70A6B20011; Thu, 19 Jun 2025 08:49:48 +0000 (UTC) Date: Thu, 19 Jun 2025 04:49:53 -0400 From: Steven Rostedt To: Peter Zijlstra Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org, x86@kernel.org, Masami Hiramatsu , Mathieu Desnoyers , Josh Poimboeuf , Ingo Molnar , Jiri Olsa , Namhyung Kim , Thomas Gleixner , Andrii Nakryiko , Indu Bhagat , "Jose E. Marchesi" , Beau Belgrave , Jens Remus , Linus Torvalds , Andrew Morton Subject: Re: [PATCH v10 06/14] unwind_user/deferred: Add deferred unwinding interface Message-ID: <20250619044953.630c349a@batman.local.home> In-Reply-To: <20250619080108.GY1613376@noisy.programming.kicks-ass.net> References: <20250611005421.144238328@goodmis.org> <20250611010428.770214773@goodmis.org> <20250618142000.GS1613376@noisy.programming.kicks-ass.net> <20250618113706.2eb46544@gandalf.local.home> <20250619080108.GY1613376@noisy.programming.kicks-ass.net> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) 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-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 70A6B20011 X-Stat-Signature: wm8mdhhxwsab9enitotenb1s4y6gfb3r X-Rspamd-Server: rspamout05 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Session-ID: U2FsdGVkX1+m9RaEQFiWcConn3hFsX2R58+fX92JsoU= X-HE-Tag: 1750322988-760678 X-HE-Meta: U2FsdGVkX19ItN7KcrqT3FzBR8Bm28K8TnxtDsJL/KxHZ+vHOPUqMdz5SmRXrau124q3SQQJYemftlaLRX67QqjcHj4zpZRxdM8hF4lxz32ei7WwobXcl27K68b+tKhTZgbk+uPGmXrtVFMcWQSarkzIxwyuG2rrAU3Vh8+4D9F1ZdXqAyGdE/oj0PNUXXHEV4MPhOI1X8xsIi3PRwDivWX2pmpw5JK7+xny1u4m+3B0D1r+FEUscmLWESdNcdao3i2O9STRZlSK2US6KDZGcWuewZpDYUFzri1kugojVDcNBH7oHrYAce1tpYSedi8pupgvPLJ4o4ATd48DLfve/zK1FhityT+C7reWBTkrnQ3OwYQs3w9kq4b+r0fMuz3r On Thu, 19 Jun 2025 10:01:08 +0200 Peter Zijlstra wrote: > If you want to rely on consecutive system calls never seeing the same > timestamp, let alone PID reuse in the same timestamp -- for some generic > infrastructure -- you need to go audit all the arch code. I can drop the timestamp and go back to the original "cookie" generation that guaranteed unique ids for something like 2^48 system calls per task. I thought the timestamps just made it easier. But having to audit every arch, may make that not the case. -- Steve