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 78AB720B3E; Tue, 23 Apr 2024 21:42:31 +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=1713908551; cv=none; b=oOrx7Ru7iz9Msr8CsO0SPynb7aUVRhJWlV7/nu+LFe5osntwJDXalf9HPWqvv+0no/kcPeN8nq1aYkkfvo5JukG1AfsN1hUfN/tAYEL72F5vyoM9t95vzvIBA6Y6QYH8475mXbju4PBq6n8krotoHGHo7+Jac1HJGvXR6lX2Ji0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713908551; c=relaxed/simple; bh=TxZ12yq1/puCaLG4Q/uV82F/X6dPU3Cs2whN6dKGpgk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=IPgtjBWAxx0FWA2Xw6g6XcRHhYAKmsB0Ut0ifWAXfI3jk4NStJPMB9nbNKC2Uq+ROiHCDrNEIiHSEblGdBo4fCzmNUnvhAlzKajTarLJiVRUFshTp2VI/JKuJ7aNwmvChdzkIBfo8uHIsypqCxUke9fLen7YK0TaMvGeZe+GnU0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ryMBh/gG; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="ryMBh/gG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 468D4C32783; Tue, 23 Apr 2024 21:42:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1713908551; bh=TxZ12yq1/puCaLG4Q/uV82F/X6dPU3Cs2whN6dKGpgk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ryMBh/gGaMNXJwvnRPDWbLx/UBUq7/HiyS/BQgpqKDe4y9+xMIxZ6n6V66CXiTBhS y5bUFoWmVY1UYRt/ioPEIQZcGU+JdhQ3UnNZiXmQiyXbHWAaUjd3dzUnfkqv6PIPax hurep3/S//I5AunPnyajO9R89l+NFVJg5kQZ3AJ8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Miaohe Lin , Thorvald Natvig , Jane Chu , Christian Brauner , Heiko Carstens , Kent Overstreet , "Liam R. Howlett" , Mateusz Guzik , "Matthew Wilcox (Oracle)" , Muchun Song , Oleg Nesterov , Peng Zhang , Tycho Andersen , Andrew Morton Subject: [PATCH 6.8 152/158] fork: defer linking file vma until vma is fully initialized Date: Tue, 23 Apr 2024 14:39:34 -0700 Message-ID: <20240423213900.780826104@linuxfoundation.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240423213855.824778126@linuxfoundation.org> References: <20240423213855.824778126@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.8-stable review patch. If anyone has any objections, please let me know. ------------------ From: Miaohe Lin commit 35e351780fa9d8240dd6f7e4f245f9ea37e96c19 upstream. 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 Signed-off-by: Greg Kroah-Hartman --- kernel/fork.c | 33 +++++++++++++++++---------------- 1 file changed, 17 insertions(+), 16 deletions(-) --- a/kernel/fork.c +++ b/kernel/fork.c @@ -712,6 +712,23 @@ 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; @@ -728,25 +745,9 @@ 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;