From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4E4B66EB4E; Tue, 16 Apr 2024 22:40:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713307234; cv=none; b=Pq4eZe4gnP4+ff5DEGDyFrDpFY9PzYnoxLMr0gqO+Yc42qSL9fEM3As4Db2q8G4lsM3beOoDYuEZn4w2luKuneWcxJBwQ4V4y3ROoKr5CS6wLvWidLRU0s3kl0TBnK39wNaCu/+E8+p4RBi+K/Mw4Rs3n58q8AS8SqxMeDamH1s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713307234; c=relaxed/simple; bh=yY/3Wci30LhkFQT5dSOwZYr9rt04OO1zkncKXdyZq2Y=; h=Date:To:From:Subject:Message-Id; b=d6dJ7YO1Y668NoiztN/Vtq2LnZa2tOedLt4/ZzjzGZck4Ze9gW/On51XEqLnOF+aCc7d6D11m2K2xqVSI0OzmUYhtNJg4EB3PaoSjE7qUbO9GzWOhnACAMsw2ZOhd6jAnOYt5R/+6xLUPRVEJw6mMyeHdptwy+Xb+RsMz4eZDwk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=kVUj7h3K; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="kVUj7h3K" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2533BC113CE; Tue, 16 Apr 2024 22:40:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1713307234; bh=yY/3Wci30LhkFQT5dSOwZYr9rt04OO1zkncKXdyZq2Y=; h=Date:To:From:Subject:From; b=kVUj7h3K4iVUtlUnS5Chn+wllxyR61H6OI6NEL535mG6KLURugWDXMpxiwoagIWtD ok5YCmHmho/7NtD7pZHg3/sUdXlaeUvZISyUC57SnuXpOb0g00uPz9Ew1pxxjo/yn2 UWFakxUbeO+8AmBwcY05ENz+p/05AyovS5v88AEk= Date: Tue, 16 Apr 2024 15:40:33 -0700 To: mm-commits@vger.kernel.org,zhangpeng.00@bytedance.com,willy@infradead.org,thorvald@google.com,tandersen@netflix.com,stable@vger.kernel.org,oleg@redhat.com,muchun.song@linux.dev,mjguzik@gmail.com,Liam.Howlett@oracle.com,kent.overstreet@linux.dev,jane.chu@oracle.com,hca@linux.ibm.com,brauner@kernel.org,linmiaohe@huawei.com,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-hotfixes-stable] fork-defer-linking-file-vma-until-vma-is-fully-initialized.patch removed from -mm tree Message-Id: <20240416224034.2533BC113CE@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: fork: defer linking file vma until vma is fully initialized has been removed from the -mm tree. Its filename was fork-defer-linking-file-vma-until-vma-is-fully-initialized.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Miaohe Lin Subject: fork: defer linking file vma until vma is fully initialized Date: Wed, 10 Apr 2024 17:14:41 +0800 Thorvald reported a WARNING [1]. And the root cause is below race: CPU 1 CPU 2 fork hugetlbfs_fallocate dup_mmap hugetlbfs_punch_hole i_mmap_lock_write(mapping); vma_interval_tree_insert_after -- Child vma is visible through i_mmap tree. i_mmap_unlock_write(mapping); hugetlb_dup_vma_private -- Clear vma_lock outside i_mmap_rwsem! i_mmap_lock_write(mapping); hugetlb_vmdelete_list vma_interval_tree_foreach hugetlb_vma_trylock_write -- Vma_lock is cleared. tmp->vm_ops->open -- Alloc new vma_lock outside i_mmap_rwsem! hugetlb_vma_unlock_write -- Vma_lock is assigned!!! i_mmap_unlock_write(mapping); hugetlb_dup_vma_private() and hugetlb_vm_op_open() are called outside i_mmap_rwsem lock while vma lock can be used in the same time. Fix this by deferring linking file vma until vma is fully initialized. Those vmas should be initialized first before they can be used. Link: https://lkml.kernel.org/r/20240410091441.3539905-1-linmiaohe@huawei.com Fixes: 8d9bfb260814 ("hugetlb: add vma based lock for pmd sharing") Signed-off-by: Miaohe Lin Reported-by: Thorvald Natvig Closes: https://lore.kernel.org/linux-mm/20240129161735.6gmjsswx62o4pbja@revolver/T/ [1] Reviewed-by: Jane Chu Cc: Christian Brauner Cc: Heiko Carstens Cc: Kent Overstreet Cc: Liam R. Howlett Cc: Mateusz Guzik Cc: Matthew Wilcox (Oracle) Cc: Miaohe Lin Cc: Muchun Song Cc: Oleg Nesterov Cc: Peng Zhang Cc: Tycho Andersen Cc: Signed-off-by: Andrew Morton --- kernel/fork.c | 33 +++++++++++++++++---------------- 1 file changed, 17 insertions(+), 16 deletions(-) --- a/kernel/fork.c~fork-defer-linking-file-vma-until-vma-is-fully-initialized +++ a/kernel/fork.c @@ -714,6 +714,23 @@ static __latent_entropy int dup_mmap(str } else if (anon_vma_fork(tmp, mpnt)) goto fail_nomem_anon_vma_fork; vm_flags_clear(tmp, VM_LOCKED_MASK); + /* + * Copy/update hugetlb private vma information. + */ + if (is_vm_hugetlb_page(tmp)) + hugetlb_dup_vma_private(tmp); + + /* + * Link the vma into the MT. After using __mt_dup(), memory + * allocation is not necessary here, so it cannot fail. + */ + vma_iter_bulk_store(&vmi, tmp); + + mm->map_count++; + + if (tmp->vm_ops && tmp->vm_ops->open) + tmp->vm_ops->open(tmp); + file = tmp->vm_file; if (file) { struct address_space *mapping = file->f_mapping; @@ -730,25 +747,9 @@ static __latent_entropy int dup_mmap(str i_mmap_unlock_write(mapping); } - /* - * Copy/update hugetlb private vma information. - */ - if (is_vm_hugetlb_page(tmp)) - hugetlb_dup_vma_private(tmp); - - /* - * Link the vma into the MT. After using __mt_dup(), memory - * allocation is not necessary here, so it cannot fail. - */ - vma_iter_bulk_store(&vmi, tmp); - - mm->map_count++; if (!(tmp->vm_flags & VM_WIPEONFORK)) retval = copy_page_range(tmp, mpnt); - if (tmp->vm_ops && tmp->vm_ops->open) - tmp->vm_ops->open(tmp); - if (retval) { mpnt = vma_next(&vmi); goto loop_out; _ Patches currently in -mm which might be from linmiaohe@huawei.com are