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bh=3Ad8ik7IFSyx7voLIMN7w0BRCBgrkaim2ypdKamKnu4=; b=fLInNBs8TXqUHGtP3Sh1sI6ytVwTqfBLr12hBnrz+MA8vrF5DTVkSUXNqFbzywP456lNeB ez73iUWVfEsf7FI0j6ikXXxHMfwNimMtiy7rW8tC5ZhcKUxZU29BYos4u2BXpsCC5Ald34 Vs0GfoQublaZnEOiSv48K7uNCrPlu07CIS0rI3lgaEBNIk8gpzEjvWrfezSP+0BW7PTEpx J8wjLrzxdRXyxoQKeZi0kBumr+eR2LmUSOrGj8xPUOqnMccqZfx0+qYvS5U941NFYPFFZS PrZb9p0STUdw3Zxv3qYbCkZlJXkHt0KmsNyzGv9MQX3zaLVbHr0vTtdeG4MNJw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1764228059; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=3Ad8ik7IFSyx7voLIMN7w0BRCBgrkaim2ypdKamKnu4=; b=dk5SuCbOQvbURXCZeKYw/C9ynGOXmOuzOVf9ofmc8gtUWPcmsiNWWOsyOjHAZ0L3i9i8YU ZNHJRX1mAseyi7CQ== From: Sebastian Andrzej Siewior To: Xie Yuanbin Cc: viro@zeniv.linux.org.uk, linux@armlinux.org.uk, will@kernel.org, david.laight@runbox.com, rmk+kernel@armlinux.org.uk, brauner@kernel.org, jack@suse.cz, 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, catalin.marinas@arm.com, rppt@kernel.org, vbabka@suse.cz, pfalcato@suse.de, lorenzo.stoakes@oracle.com, kuninori.morimoto.gx@renesas.com, tony@atomide.com, arnd@arndb.de, punitagrawal@gmail.com, rjw@rjwysocki.net, marc.zyngier@arm.com, 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: <20251127072057.EbvhUyG4@linutronix.de> References: <20251127030316.8396-1-xieyuanbin1@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20251127030316.8396-1-xieyuanbin1@huawei.com> X-Rspamd-Server: rspam12 X-Rspam-User: X-Rspamd-Queue-Id: AF8FE14000F X-Stat-Signature: 4prn5ri7ogxcfkftwgzx1gxbefoujt6i X-HE-Tag: 1764228061-350115 X-HE-Meta: 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 BaaeTTBP QSYE/wLMd4LHhZWiKNCDZLmhFF+KpCzzwt3OYewf7vvRfjK/4PO0tiiZ2EhKajwGgrxVZWw2ccbwxyU4Tme66hwdFdbt/acmW3Xs/a27urTudkaByaxmq6BHCosd8mf8bDjXYIJTE8fgaLa5EFqvonY4oEhAgsbBRW+uC7WRaTzvXY+s2a9B2GZvUPCNdTxkRjtRYhRsr/9wm7hc/5YRw5neIrq0x50NLY1vXnxzH24CBAIhACjDjnuo2/calSIxuESuwkKo4IQNd87t0MSwstMooo7hZxjn/srRqPDLTwYz3Oj11HuEtkm7rZ4PT7S9SfiC5uoFw6A4CTDn52t4qHlkgXcGHKTKWvG77NfClJaOIeBg= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2025-11-27 11:03:16 [+0800], Xie Yuanbin wrote: > On, Wed, 26 Nov 2025 19:26:40 +0000, Al Viro wrote: > > 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? > > On, Wed, 26 Nov 2025 23:31:00 +0000, Russell King (Oracle) wrote: > > Now, for 32-bit ARM, I think I am coming to the conclusion that Al's > > suggestion is probably the easiest solution. However, whether it has > > side effects, I couldn't say - the 32-bit ARM fault code has been > > modified by quite a few people in ways I don't yet understand, so I > > can't be certain at the moment whether it would cause problems. > > I think I've already submitted a very similar patch, to fix another bug: > On Thu, 16 Oct 2025 20:16:21 +0800, Xie Yuanbin wrote: > > +#ifdef CONFIG_HARDEN_BRANCH_PREDICTOR > > + if (unlikely(addr > TASK_SIZE) && user_mode(regs)) { > > + fault = 0; > > + code = SEGV_MAPERR; > > + goto bad_area; > > + } > > +#endif > Link: https://lore.kernel.org/20250925025744.6807-1-xieyuanbin1@huawei.com > > However, the patch seems to have received no response for a very long > time. This all should be covered by the series here https://lore.kernel.org/all/20251110145555.2555055-1-bigeasy@linutronix.de/ or do I miss something. Sebastian