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Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: <20221214200453.1772655-2-peterx@redhat.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.151.185] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To canpemm500002.china.huawei.com (7.192.104.244) X-CFilter-Loop: Reflected X-Rspamd-Queue-Id: E34E840005 X-Rspamd-Server: rspam09 X-Rspam-User: X-Stat-Signature: nyrr83nzxkkjz6qim5zj6mpjsie55diy X-HE-Tag: 1671245951-2966 X-HE-Meta: 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 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: On 2022/12/15 4:04, Peter Xu wrote: > When fork(), dst_vma is not guaranteed to have VM_UFFD_WP even if src may > have it and has pte marker installed. The warning is improper along with > the comment. The right thing is to inherit the pte marker when needed, or > keep the dst pte empty. > > A vague guess is this happened by an accident when there's the prior patch > to introduce src/dst vma into this helper during the uffd-wp feature got > developed and I probably messed up in the rebase, since if we replace > dst_vma with src_vma the warning & comment it all makes sense too. > > Hugetlb did exactly the right here (copy_hugetlb_page_range()). Fix the > general path. > > Reproducer: > > https://github.com/xupengfe/syzkaller_logs/blob/main/221208_115556_copy_page_range/repro.c > > Cc: # 5.19+ > Fixes: c56d1b62cce8 ("mm/shmem: handle uffd-wp during fork()") > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=216808 > Reported-by: Pengfei Xu > Signed-off-by: Peter Xu Looks good to me. Thanks. Reviewed-by: Miaohe Lin Thanks, Miaohe Lin