From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) (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 E908821FF5F; Tue, 7 Oct 2025 19:48:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=216.40.44.13 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759866532; cv=none; b=TG1C+QkQKwkiOAvD3Rq/LX4zEs7vAoiBlmWOF+yWA3F02PrG5h0iaPIudzR6ae4UTF0JSk2e66DU33dopvGF45TLpTifI1jSwjp6C+t26Ldq0vc3H7DgrtTFTP1vSLfoZ7nRJLhvSiimRi9Qfmt109cld8gbJTCW8HnNhJs4fRo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759866532; c=relaxed/simple; bh=nOHANFyCsFyXoIL9liUDQHLiSZZA1TpLU3yTBKW3+gE=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=g6PE9zR0o7O1Z0mUz/EhWZmgE+qWfqeL9ApSft6sTsSVULkVILxaUA5BIo3avjXXDcw4cMFFmNz7iAYRuGHhL1wCsYwfXVh1t+qce4AkceoyeI4hUz6SdUTTRGYk/6MZnb6rTorW3MYHfDuf11/nOPmLee2Ev+JpDShPOspWyUw= 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=216.40.44.13 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 omf16.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 198741DE2F0; Tue, 7 Oct 2025 19:41:19 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: rostedt@goodmis.org) by omf16.hostedemail.com (Postfix) with ESMTPA id B4F9E2000D; Tue, 7 Oct 2025 19:41:16 +0000 (UTC) Date: Tue, 7 Oct 2025 15:43:08 -0400 From: Steven Rostedt To: Runping Lai Cc: Masami Hiramatsu , Mathieu Desnoyers , Wattson CI , kernel-team@android.com, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Luo Gengkun , Linus Torvalds Subject: Re: [PATCH v1] Revert "tracing: Fix tracing_marker may trigger page fault during preempt_disable" Message-ID: <20251007154308.5b158d04@gandalf.local.home> In-Reply-To: References: <20251007003417.3470979-2-runpinglai@google.com> <20251006221043.07cdb0fd@gandalf.local.home> X-Mailer: Claws Mail 3.20.0git84 (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-Stat-Signature: urxnjt669bhdc6wji94s6qkr5tqjcu4r X-Rspamd-Server: rspamout07 X-Rspamd-Queue-Id: B4F9E2000D X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Session-ID: U2FsdGVkX1+hVXlRtvcPL61t77f+RImbITjCuVK+6UA= X-HE-Tag: 1759866076-65905 X-HE-Meta: U2FsdGVkX1/ted36HpkHF++cHmrIJsIRMDKanGvtSPlNTJnNDqXm1h2aBdGzxhF8rJ1nbxJML56GqUrcdDHz9Tl/gpA6fU8Uj0pm2UMOOPdUhraLMZuSTByNQ9DtH8rrkM/eh+QBP4z27Oiah3phjWhGuTP8hRLhvL8rDV+UKJyqdliVCsmwCzIeDy/qTzC5rqukCYdUiGD4K+TP5CsUFJV3uJ8z3sieWq9Z+PpELJQpbprl2aAKrmcxNiB9PDq1DO/PWaAMy8j4p1JyeBR+tDAHCFS+TG3KthTU4kZtbR1FM1xxh1UCevkVK3GMgp6Gq7PUHtSCw2x9H1Td2JkACCFzy6NwtECF On Tue, 7 Oct 2025 11:19:34 -0700 Runping Lai wrote: > Hey Steve, > > On Pixel6, CONFIG_PREEMPT is set. And CONFIG_PREEMPT_NONE > is not set. I'll paste the full PREEMPT configs: Hmm, now I'm curious to why _nofault() does't work but inatomic does. > > > > > The original code is buggy, but if this is causing a regression, then we > > likely need to do something else, like copy in a pre-allocated buffer? > > Sounds like a good plan. Before the long term fix, can we please > revert this commit? Not that easy as the old way has a legitimate bug in it. Could you see if adding pagefault_disable() and pagefault_enable() around the __copy_from_user_inatomic() works for you? Or does that have the same problem? I do have a working solution, but it isn't trivial. -- Steve