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David Alan Gilbert" , "Matthew Wilcox (Oracle)" , Vlastimil Babka , Baolin Wang , Miaohe Lin , Yang Shi , Frank van der Linden , Jiaqi Yan , linux-mm@kvack.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: A31FD180009 X-Stat-Signature: 8hw4ke613f4jdqrwazbjf9uux15gnsub X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1677261948-304805 X-HE-Meta: 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 CaI9REMy kocuXwipTMmAAdHJsHGnYSp3K8IMlqFT3DnevGvkEO03yKW+qc85zXuE83aNrUofb0lDLodBFyz9ZOWNmZOZeasWHp5vamUSphFrHU4HMY7i/JrjKRW6ImMzdezNSwkvKvNAXulUpbQRC1qwZPWCkCoS0afKUE1Xx5fjywCHR36hgppL3Wq8DJ2tHJuWOvXad02YVuf8uQ/o7nbRx1LShIUr8uDkqbk5JTMR7ZbvWeaDL3+FH7fJDPhW3uM5eRtak+rr0MjfhT4vX+e0= 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 Fri, Feb 24, 2023 at 9:42 AM James Houghton wrote: > > > @@ -5397,7 +5397,10 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, > > } else { > > ptepage = pte_page(entry); > > hpage = compound_head(ptepage); > > - get_page(hpage); > > + if (try_get_page(hpage)) { > > + ret = -EFAULT; > > + break; > > spin_unlock(src_ptl) and spin_unlock(dst_ptl) is required here. > > I'll make sure there's a selftest that actually makes sure that > refcount overflowing is handled gracefully for v3. And this should be !try_get_page(). This hunk was a last-minute addition to this commit; apparently I hadn't retested fork() after I made this change. Sorry! The hugetlb-hgm selftest immediately catches this problem. - James