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 4ACD2134427 for ; Tue, 23 Apr 2024 13:10:29 +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=1713877829; cv=none; b=hJX5ajghs0SNySWiGvZZ4jdY7XRoFXzzwe7kALZw21ONKtI5oaoSRnUeroYP7lBwldUdRUEnKCVJHukDH8tEo6oCjIDeah7ERH7IDtyFNut/VmLSO5TbFgDiNKYJLBzQQoYn989P9+SSK4NgCIhY0rmvcR8kJFLZFW0qxWdXFnQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713877829; c=relaxed/simple; bh=fmrz6UDnel8j05vui1cQvEaAnu3YYxQM59P6HYl8DiQ=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=sJXyI1gyxMckBU0iudK8mWiOT+asVWr/94mcEWsPFiAHqk9/N+6kx9gNpA8CHNWTWHF/b2ujFULimbsOkLmheInnPV4eAWIDDw8RJl/9FGDkqyCgw3sICQ4kUcCIKk4yec13jb3fEdfWpaU2WDnvX2oOzBIqoPnHMYFQ2bRCRNk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=RQuyq/01; 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="RQuyq/01" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E2E2DC116B1; Tue, 23 Apr 2024 13:10:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1713877829; bh=fmrz6UDnel8j05vui1cQvEaAnu3YYxQM59P6HYl8DiQ=; h=Subject:To:Cc:From:Date:From; b=RQuyq/01KK3hjejlGG8StW6vBzKjlMYVgj/CvrMAsyZ/KtnaaoqdAfxrUK8UAPbL1 oYDOigNdbwEd1gvJ9axG+D3rkEwPJACaYcvJnOy52UVtOAr8vyAHlk2p+VnqYWKFik Chcy3t63IARPDfEXlSDTKOOyrxS5aBOH7cfv490o= Subject: FAILED: patch "[PATCH] fork: defer linking file vma until vma is fully initialized" failed to apply to 6.6-stable tree To: linmiaohe@huawei.com,Liam.Howlett@oracle.com,akpm@linux-foundation.org,brauner@kernel.org,hca@linux.ibm.com,jane.chu@oracle.com,kent.overstreet@linux.dev,mjguzik@gmail.com,muchun.song@linux.dev,oleg@redhat.com,stable@vger.kernel.org,tandersen@netflix.com,thorvald@google.com,willy@infradead.org,zhangpeng.00@bytedance.com Cc: From: Date: Tue, 23 Apr 2024 06:10:19 -0700 Message-ID: <2024042319-freeing-degree-ca0d@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x 35e351780fa9d8240dd6f7e4f245f9ea37e96c19 # git commit -s git send-email --to '' --in-reply-to '2024042319-freeing-degree-ca0d@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: 35e351780fa9 ("fork: defer linking file vma until vma is fully initialized") d24062914837 ("fork: use __mt_dup() to duplicate maple tree in dup_mmap()") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 35e351780fa9d8240dd6f7e4f245f9ea37e96c19 Mon Sep 17 00:00:00 2001 From: Miaohe Lin Date: Wed, 10 Apr 2024 17:14:41 +0800 Subject: [PATCH] fork: defer linking file vma until vma is fully initialized 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 diff --git a/kernel/fork.c b/kernel/fork.c index 39a5046c2f0b..aebb3e6c96dc 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -714,6 +714,23 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm, } 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(struct mm_struct *mm, 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;