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Tue, 27 May 2025 11:53:43 -0400 X-MC-Unique: lKUn6eXcNjidh9a56h_-NA-1 X-Mimecast-MFC-AGG-ID: lKUn6eXcNjidh9a56h_-NA_1748361221 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 6852D195608C; Tue, 27 May 2025 15:53:40 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.44.32.4]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with SMTP id A7F3019560AB; Tue, 27 May 2025 15:53:35 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Tue, 27 May 2025 17:52:59 +0200 (CEST) Date: Tue, 27 May 2025 17:52:54 +0200 From: Oleg Nesterov To: Lorenzo Stoakes Cc: Pu Lehui , mhiramat@kernel.org, peterz@infradead.org, akpm@linux-foundation.org, Liam.Howlett@oracle.com, vbabka@suse.cz, jannh@google.com, pfalcato@suse.de, linux-mm@kvack.org, linux-kernel@vger.kernel.org, pulehui@huawei.com Subject: Re: [RFC PATCH v2 1/2] mm/mremap: Fix uprobe anon page be overwritten when expanding vma during mremap Message-ID: <20250527155253.GE8333@redhat.com> References: <20250527132351.2050820-1-pulehui@huaweicloud.com> <20250527132351.2050820-2-pulehui@huaweicloud.com> <20250527153007.GD8333@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 X-Rspamd-Queue-Id: 4CEBB1C0005 X-Stat-Signature: nwns5qh7cq57rgbnkefs4i88rweyx5tc X-Rspam-User: X-Rspamd-Server: rspam04 X-HE-Tag: 1748361227-536881 X-HE-Meta: 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 4I15WMX9 BWGo5YYuZCCQZBZbvQRgZkhfTD6h59ju1l51v49EbBMEV10YgjCvxqHTAYApBpr9HVppw3NDuZWDe2R0pKqOKHh4A/Lml9OXy3ayejPFju8Xeq7LzOOfRSrhsIx47RC3fAFa7keW6qZFfcojGnd5hNVy9dcjbAdT4KAmGoo6b+aUTQR6gVvl15eGmY8HkKuEVUGVRczunfF3qbsEsWeDcstCHN2vZO82zFcPyi8RJJP4iGyaxcpYQveBa9uoX5OwGo7thHa5ej5WG/XEl/YiuXXYfnqUVIKxIE6vsuMA+4N8STwD019zIiQXQXZX5Ed5BcreCTewYnhiXjYGe2bu9vAK65J0pNUJqsDhpp6uQ9l73Lx0= 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 05/27, Lorenzo Stoakes wrote: > > On Tue, May 27, 2025 at 05:30:08PM +0200, Oleg Nesterov wrote: > > > > > struct perf_event_attr attr = { > > > .type = 9, > > > > Cough ;) Yes I too used perf_event_attr.type == 9 when I wrote another > > test-case. Because I am lazy and this is what I see in > > /sys/bus/event_source/devices/uprobe/type on my machine. > > > > But me should not assume that perf_pmu_register(&perf_uprobe) -> idr_alloc() > > will return 9. > > While I agree we should probably try to do this nicely, in defence of Pu I think > this is adapted from the syzkaller horror show :P and that code does tend to > just insert random integers etc. Not really ;) syzkaller's reproducer reads /sys/bus/event_source/devices/uprobe/type, see https://lore.kernel.org/all/20250521092503.3116340-1-pulehui@huaweicloud.com/ In any case. Many thanks to Lehui who investigated this problem! Oleg.