From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail115-118.sinamail.sina.com.cn (mail115-118.sinamail.sina.com.cn [218.30.115.118]) (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 49A3A188714 for ; Tue, 31 Dec 2024 08:41:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=218.30.115.118 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1735634479; cv=none; b=cYdoIIQE9PGeHA4JqbjMq9WHD4WAXuADz6y5tgVzcR3UcoPG47KyJje7QT5UdhDAp/3f5WMTQ4rIgyhJGGLLqYf1Wntz3gGjx95D8tLeKoVk0T1djp3IRGWJytj7e8YTXUPBvu+klwYSgbeAjRXV4kFJy1ooduECfPQGUbYa6m0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1735634479; c=relaxed/simple; bh=Xg1JUCXjSt0B9pJ3DGBgq551TZ9236z1F+bU7t/g7fs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=DlWr4/nsBnhkrkZMFVEql3dP0tFgxxSHnNFQeDwXWdSIA47YJ4XXLXXi4tTqofNebzgkQ1Hev2vOfYmUSJ0T4dLk/1xboIBU/Nh6IwWGhZrceNXj1mpnKjenzVAdzMC/o55R5DqdLDqI8IWzUJp6a44HaFh3A+pP2QpeYjY750U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sina.com; spf=pass smtp.mailfrom=sina.com; arc=none smtp.client-ip=218.30.115.118 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sina.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sina.com X-SMAIL-HELO: localhost.localdomain Received: from unknown (HELO localhost.localdomain)([116.24.8.103]) by sina.com (10.185.250.24) with ESMTP id 6773AE1F00001CDD; Tue, 31 Dec 2024 16:41:05 +0800 (CST) X-Sender: hdanton@sina.com X-Auth-ID: hdanton@sina.com Authentication-Results: sina.com; spf=none smtp.mailfrom=hdanton@sina.com; dkim=none header.i=none; dmarc=none action=none header.from=hdanton@sina.com X-SMAIL-MID: 88493710748298 X-SMAIL-UIID: 7CAB75E5FAC14BB89050619685021546-20241231-164105-1 From: Hillf Danton To: syzbot Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] [mm?] WARNING in __folio_rmap_sanity_checks (2) Date: Tue, 31 Dec 2024 16:41:06 +0800 Message-ID: <20241231084108.1146-1-hdanton@sina.com> In-Reply-To: <676f84f5.050a0220.2f3838.0493.GAE@google.com> References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Fri, 27 Dec 2024 20:56:21 -0800 > syzbot has found a reproducer for the following issue on: > > HEAD commit: 8155b4ef3466 Add linux-next specific files for 20241220 > git tree: linux-next > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1652fadf980000 #syz test --- x/mm/filemap.c +++ y/mm/filemap.c @@ -3636,6 +3636,10 @@ static vm_fault_t filemap_map_folio_rang continue; skip: if (count) { + for (unsigned int i = 0; i < count; i++) { + if (page_folio(page + i) != folio) + goto out; + } set_pte_range(vmf, folio, page, count, addr); *rss += count; folio_ref_add(folio, count); @@ -3658,6 +3662,7 @@ skip: ret = VM_FAULT_NOPAGE; } +out: vmf->pte = old_ptep; return ret; @@ -3702,7 +3707,7 @@ vm_fault_t filemap_map_pages(struct vm_f struct file *file = vma->vm_file; struct address_space *mapping = file->f_mapping; pgoff_t file_end, last_pgoff = start_pgoff; - unsigned long addr; + unsigned long addr, pmd_end; XA_STATE(xas, &mapping->i_pages, start_pgoff); struct folio *folio; vm_fault_t ret = 0; @@ -3731,6 +3736,12 @@ vm_fault_t filemap_map_pages(struct vm_f if (end_pgoff > file_end) end_pgoff = file_end; + /* make vmf->pte[x] valid */ + pmd_end = ALIGN(addr, PMD_SIZE); + pmd_end = (pmd_end - addr) >> PAGE_SHIFT; + if (end_pgoff - start_pgoff > pmd_end) + end_pgoff = start_pgoff + pmd_end; + folio_type = mm_counter_file(folio); do { unsigned long end; --