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Received: from viro by zeniv.linux.org.uk with local (Exim 4.99 #2 (Red Hat Linux)) id 1vPC3C-00000000XUf-1HpY; Sat, 29 Nov 2025 03:55:10 +0000 Date: Sat, 29 Nov 2025 03:55:10 +0000 From: Al Viro To: Zizhi Wo Cc: Will Deacon , Linus Torvalds , jack@suse.com, brauner@kernel.org, hch@lst.de, akpm@linux-foundation.org, linux@armlinux.org.uk, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, yangerkun@huawei.com, wangkefeng.wang@huawei.com, pangliyuan1@huawei.com, xieyuanbin1@huawei.com Subject: Re: [Bug report] hash_name() may cross page boundary and trigger sleep in RCU context Message-ID: <20251129035510.GI3538@ZenIV> References: <20251126090505.3057219-1-wozizhi@huaweicloud.com> <9ff0d134-2c64-4204-bbac-9fdf0867ac46@huaweicloud.com> <39d99c56-3c2f-46bd-933f-2aef69d169f3@huaweicloud.com> <61757d05-ffce-476d-9b07-88332e5db1b9@huaweicloud.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam12 X-Rspam-User: X-Rspamd-Queue-Id: 09FBB14000C X-Stat-Signature: ga1y5m9omjwpzd9d4p1aizj89bgofwgj X-HE-Tag: 1764388506-94197 X-HE-Meta: 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 0D26Xbhp BmaR4zKjBAtCH4BR4d+cFVBHyhdU/IsBBZNW5IjrsZ0AVGGPgxIMqMuxQP6k2UTvO4JDaXzhsQNrjN+H/DRbdRwO4hu+d6PezhHXXBwxL1sqo/kNKIqT7tkAhIJX3Ul4tIm7v7xX78GWnITaLfMZJUU+AN3xzVkjU4TUipftXEzFXjnOOJxWwMAsc7X6Iidaw+7mDigF3cwjyAq8fMh2Zd0H3YtASa4sqL6GK5nDnO2wG3h6de7eLA4y5zWxU5kiYrlcrWSF6PEGGSMUlabOefl0nGYdTcx0ywJTx4WAHsJfhdqOBeIhknlQ7++f3xLmAXONlxu2Uf30LQMKBmDE0Ne3cUZvjsEcqj+IzGckoc1CmCJpCu+6FRqWrEZDv1TjNRvEQ6D0gga8h1QFg6UPSjc2WJQF9ZldkS1B6fp1cFRYurKLQIM45wVE4EOvS/LE9Fp/bvOey0kqUfBK41YF/6CAHCho1ONzzRPBKUStUzp9I0fc= 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 Sat, Nov 29, 2025 at 09:02:27AM +0800, Zizhi Wo wrote: > Thank you very much for the answer. For the vmalloc area, I checked the > call points on the vfs side, such as dentry_string_cmp() or hash_name(). > Their "names addr" are all assigned by kmalloc(), so there should be no > corresponding issues. But I'm not familiar with the other calling > points... Pathname might be a symlink body, sitting in page cache or whatever ->get_link() has returned...