From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id F0EEACA0FF9 for ; Sat, 30 Aug 2025 00:51:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:MIME-Version:References:In-Reply-To:Message-ID:Subject:Cc:To: From:Date:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=5U+goY9HWQ27/P5JEY+pmtiYgDqF62fvXL6YUIqRfek=; b=RkxtFIV5TSodohLMSDHT9DxLyi TfJdnEIc1pzmQ3ySQSl53ccCav+li+H3vjB4JIMfbvkkdN0Rto7FGEGvCirUrXA1pTkUz31ID713/ 48iWDJ65rB2rx+Im7EvvXERd93CCUIR2t8KpC8n4VKs7vcvSeJ5u1yNs1dlXxK1dcMLEGmmSojQtV D8sRePvUqjq7gopl4hp56cc8/9nhB16gHd7sNqac+74v8EXWFZzTylx1aRp3mdPdh/walQTdaQMoG Bz8soQPGjV2o+cc3PlooYKxzyLPlXBVpa8v/q5rM1O59czmSwaob+g05ImibaBGfIRd0e1bpWhUJs s8YGIFmQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1us9oc-00000007Cje-3Pcu; Sat, 30 Aug 2025 00:51:34 +0000 Received: from smtprelay0011.hostedemail.com ([216.40.44.11] helo=relay.hostedemail.com) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1us7L4-00000006vri-1EPO for linux-arm-kernel@lists.infradead.org; Fri, 29 Aug 2025 22:12:55 +0000 Received: from omf12.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 3F9C91DE8E3; Fri, 29 Aug 2025 22:12:51 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: rostedt@goodmis.org) by omf12.hostedemail.com (Postfix) with ESMTPA id E18871B; Fri, 29 Aug 2025 22:12:48 +0000 (UTC) Date: Fri, 29 Aug 2025 18:13:11 -0400 From: Steven Rostedt To: Catalin Marinas Cc: Luo Gengkun , mhiramat@kernel.org, mathieu.desnoyers@efficios.com, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Will Deacon , linux-arm-kernel@lists.infradead.org, Mark Rutland , Al Viro Subject: Re: [PATCH] tracing: Fix tracing_marker may trigger page fault during preempt_disable Message-ID: <20250829181311.079f33bf@gandalf.local.home> In-Reply-To: References: <20250819105152.2766363-1-luogengkun@huaweicloud.com> <20250819135008.5f1ba00e@gandalf.local.home> <436e4fa7-f8c7-4c23-a28a-4e5eebe2f854@huaweicloud.com> <20250829082604.1e3fd06e@gandalf.local.home> <20250829083655.3d38d02b@gandalf.local.home> X-Mailer: Claws Mail 3.20.0git84 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspamout04 X-Rspamd-Queue-Id: E18871B X-Stat-Signature: c6a9kj37bdpft57yro8x4x8gytdtbg61 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Session-ID: U2FsdGVkX1+BzqdLgt0UUBPnn0bUVIRcLzHPfZXhaf8= X-HE-Tag: 1756505568-420285 X-HE-Meta: U2FsdGVkX1+14SMITpDCqwGTTTH7u0ktZr86FlAwNfKMViAM1uVorStxHxg11gX6GdOLBRu2vlQ4xdJkmMqr/kU+y6jRplHrVO6FKm5/xCTVupKlj21B55P9/239Ph4KAg7piebRvoYzfvpmWdh73CYiF9GDVXIS6AsG36AeDl7MA11cHJx+KQl7CB05DS7uf5OeA46zbfRfB0jkQ1b9lHGdHXgPj7lT8mpIcUiLZRmDDaebBdyTa3H4A2MpDf/AhLsQ6HYnUkKrsD7DR3NW4TVog5jibbaUF6510386z0o+mr7p5el21WqVcmSS32KyBFviWF5hdcpJXO25vdTSofz/Fxy/jL39Bk/pMYZXKc1UaQsG0vIIkFErOrK6toaF X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250829_151254_397591_A20E01F9 X-CRM114-Status: GOOD ( 13.23 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, 29 Aug 2025 20:53:40 +0100 Catalin Marinas wrote: valid user address. > > BTW, arm64 also bails out early in do_page_fault() if in_atomic() but I > suspect that's not the case here. > > Adding Al Viro since since he wrote a large part of uaccess.h. > So, __copy_from_user_inatomic() is supposed to be called if pagefault_disable() has already been called? If this is the case, can we add more comments to this code? I've been using the inatomic() version this way in preempt disabled locations since 2016. Looks like it needs to be converted to copy_from_user_nofault(). Luo, this version of the patch looks legit, no need for a v2. I just wanted to figure out why __copy_from_user_inatomic() wasn't atomic. If anything, it needs to be better documented. -- Steve