From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) (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 B4BEF1B4257; Mon, 22 Sep 2025 14:42:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=216.40.44.14 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758552166; cv=none; b=eY3r9s2QGw7vcdDMnUgCjPIFH08EO7+vrI/xKMrE+wIN3c5+tlyYMC/9SWQzEPC3VYhcqNTaFBLJ/pcyyEei1kL+LZV8GmwJCqKCTsPq4jxyixs/Eiq6DSjD4y5tkSw6VjPtewjtkE0gfvMWQGDrZk21QzUviDGe/tAyqU36Bb8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758552166; c=relaxed/simple; bh=Fy9oWw8EZpU9EKlvXhF7WepyC69BvXaMNw2K16O/hMo=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=BMH1c2zUoMTBkavs2QND2A3NQBVLnJDiH7+ntt4lqCRhZ7OKAORNJxiqwnbmiY/dVTuI4gduvL2qo31ceGZl7eoeVqhaqg/7dRcDxLMdJxiLqx9a4Nlvex2Kkend0v4szBrv9R332bfRwHXk+m3dtwCMzsWUbWlDPiGuCtj06as= 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=216.40.44.14 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 omf14.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 83C1DB1FCD; Mon, 22 Sep 2025 14:42:36 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: rostedt@goodmis.org) by omf14.hostedemail.com (Postfix) with ESMTPA id 2F1CE34; Mon, 22 Sep 2025 14:42:31 +0000 (UTC) Date: Mon, 22 Sep 2025 10:42:28 -0400 From: Steven Rostedt To: Jiri Olsa Cc: Masami Hiramatsu , Peter Zijlstra , Steven Rostedt , Menglong Dong , tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, kees@kernel.org, samitolvanen@google.com, rppt@kernel.org, luto@kernel.org, ast@kernel.org, andrii@kernel.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org Subject: Re: [PATCH] tracing: fgraph: Protect return handler from recursion loop Message-ID: <20250922104228.4993227e@batman.local.home> In-Reply-To: References: <20250918120939.1706585-1-dongml2@chinatelecom.cn> <175828305637.117978.4183947592750468265.stgit@devnote2> <20250919112746.09fa02c7@gandalf.local.home> <20250922151655.1792fa0abc6c3a8d98d052c9@kernel.org> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-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: 2F1CE34 X-Stat-Signature: 5m6dza8eerdq5fheuuog9iasxo6kxxca X-Rspamd-Server: rspamout06 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Session-ID: U2FsdGVkX1+cmRNjfPhQevxwVVsrBXj76Fr4LaCEzak= X-HE-Tag: 1758552151-367461 X-HE-Meta: U2FsdGVkX1+r8iiyTWCvVbzNqGRqFSi/LZd3+qBMFsYq55nmV1rdpVsIv1x2pIXT3AHi2UMNJUvNOaozexYK45qDrN23a9Fxq/ptGTMS3MAhkSKJ47wG1rX0wsmp801U/BQ+Dc1j5poRmYDeJXOCe0EBtaMZnR/WKJGhuWTGWBECNmruc0Q/aG02YvNRfRqp7Xu7TgvElN6VAAmRuuV+YI2R+nd+SgJogu27UJTKJH9mL6kjQPQcTfIorckUwhdogLEWlr5/LBrL1851l+zUBKSCRhBOTbXBZzgA/q+GmEsZ6hKWvQ/vWkcw1ehXTQk32pG6CcOpJEpDzJ1MdaB4DATN/LK3EagD On Mon, 22 Sep 2025 15:38:13 +0200 Jiri Olsa wrote: > > I found ftrace_test_recursion_trylock() allows one nest level, can you > > make sure it is OK? > > hum, I recall being surprised by that already in the past, > I thought we fixed that somehow, will check later today It still does allow one level of recursion, because there's still locations that can trace in interrupt context before the preempt count is updated to the new context. I looked at fixing these, but IIRC, there's several locations in assembly that do this and it started getting messy. I guess I can try to fix this again. -- Steve