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 16010D11193 for ; Wed, 26 Nov 2025 19:26:51 +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:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=nU80GOb9NiCLGKUDlF0jPjWnpLtyN6G9RlF17vc6RcQ=; b=TvwpNOOQDQDIyZHX3GZbcWVYcI i0KRj4iFytmSbg+tYJHi2qbDvBuBr2hJUbEFzcw0/UY8kNN95F+fldCHWGo/Br64VBtbpL2xKrqj/ 8XkNKpZsd7Qmmzh1d2CBZGnMBsMabSncVaG2ngLUU79f51vDUUHb4D3S4phliWzgYxYRSn4IL1Hw8 udnIz6MeWXoeiBvCcVANz1Ax3S5UyyhkIyLQcyHmLHR8FkTsoyhIXdQAYvvPQ3R5s7hwoL7DJZYyw p8RDUD47JLrfv1XbSULzqkyX5qxsqfKE5gTB9k1JsTxy6URKtHxivOmCfcZz0NJJvlq3k7jHBH6Id J7pZSN5A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vOLA7-0000000FY6l-24Eq; Wed, 26 Nov 2025 19:26:47 +0000 Received: from zeniv.linux.org.uk ([2a03:a000:7:0:5054:ff:fe1c:15ff]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vOLA4-0000000FY6M-3JVw for linux-arm-kernel@lists.infradead.org; Wed, 26 Nov 2025 19:26:45 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=linux.org.uk; s=zeniv-20220401; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=nU80GOb9NiCLGKUDlF0jPjWnpLtyN6G9RlF17vc6RcQ=; b=m5IyTggrRAAY5MhBN6EpasSDVL YnL4rtLPSW0hBjjOgYMp5fLiiyp/wwm7von1AJhAekg73plC0swbRI6WCfUWNQ+P6t7lyjB2IwWHK dHG3UMGxNUmXcARXsH20a+MKTVvBYdnODh/AQrhfKkPdN/yqqcu2nz9UzxOTCwSxCeDov1UGjAWpd LRU9WIJuinhZqwhWTWmliPFSxagjI+DUY21bqlM1h0ikrfoablwBCOy2u85OE1+TvvgXc8peS4IO3 q6s2ELwC4XDldzOHD/QHYDaCIUs7has7C2uaIiYN19w0u1KZqxMxK8bdXYbLyPvUw9OW2F289fVxg elLHBApA==; Received: from viro by zeniv.linux.org.uk with local (Exim 4.99 #2 (Red Hat Linux)) id 1vOLA0-00000000kzD-2DFB; Wed, 26 Nov 2025 19:26:40 +0000 Date: Wed, 26 Nov 2025 19:26:40 +0000 From: Al Viro To: "Russell King (Oracle)" Cc: Xie Yuanbin , brauner@kernel.org, jack@suse.cz, will@kernel.org, nico@fluxnic.net, akpm@linux-foundation.org, hch@lst.de, jack@suse.com, wozizhi@huaweicloud.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, lilinjie8@huawei.com, liaohua4@huawei.com, wangkefeng.wang@huawei.com, pangliyuan1@huawei.com Subject: Re: [RFC PATCH] vfs: Fix might sleep in load_unaligned_zeropad() with rcu read lock held Message-ID: <20251126192640.GD3538@ZenIV> References: <20251126090505.3057219-1-wozizhi@huaweicloud.com> <20251126101952.174467-1-xieyuanbin1@huawei.com> <20251126181031.GA3538@ZenIV> <20251126184820.GB3538@ZenIV> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251126_112644_830312_8AB43369 X-CRM114-Status: GOOD ( 16.01 ) 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 Wed, Nov 26, 2025 at 07:05:05PM +0000, Russell King (Oracle) wrote: > On Wed, Nov 26, 2025 at 06:48:20PM +0000, Al Viro wrote: > > It's been years since I looked at 32bit arm exception handling, so I'd need > > quite a bit of (re)RTF{S,M} before I'm comfortable with poking in > > arch/arm/mm/fault.c; better let ARM folks deal with that. But arch/* is > > where it should be dealt with; as for papering over that in fs/*: > > Don't expect that to happen. I've not looked at it for over a decade, > I do very little 32-bit ARM stuff anymore. Others have modified the > fault handling, the VM has changed, I basically no longer have the > knowledge. Effectively, 32-bit ARM is unmaintained now, although it > still has many users. Joy... For quick and dirty variant (on current tree), how about adding if (unlikely(addr > TASK_SIZE) && !user_mode(regs)) goto no_context; right after if (!ttbr0_usermode_access_allowed(regs)) goto no_context; in do_page_fault() there? NOTE: that might or might not break vdso; I don't think it would, but...