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 19BF615C82 for ; Mon, 5 Dec 2022 19:14:18 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9155EC433C1; Mon, 5 Dec 2022 19:14:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1670267657; bh=3yQsfh6+Oj9ny6imetoWkcKFmnGIguwoWR5t4eQ0hM4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UCk9oZDBo62xaARunjeeqj+B/s3mhH3oagtmXwvlDtdjPbxtvFbeoKjip+Ym36myV Q9znVJ461ZQeZvGgvtVG43tNp2GCMG7RozY3IyZrXCVE3JUk2GuTkQoPhVsfoHVD2J RTl+Ben+jN37AkDKWuDBw47IhcbZSq2vH7MxtwKo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, ZhangPeng , Ryusuke Konishi , syzbot+ebe05ee8e98f755f61d0@syzkaller.appspotmail.com, Andrew Morton Subject: [PATCH 4.9 49/62] nilfs2: fix NULL pointer dereference in nilfs_palloc_commit_free_entry() Date: Mon, 5 Dec 2022 20:09:46 +0100 Message-Id: <20221205190759.950057541@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221205190758.073114639@linuxfoundation.org> References: <20221205190758.073114639@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: ZhangPeng commit f0a0ccda18d6fd826d7c7e7ad48a6ed61c20f8b4 upstream. Syzbot reported a null-ptr-deref bug: NILFS (loop0): segctord starting. Construction interval = 5 seconds, CP frequency < 30 seconds general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017] CPU: 1 PID: 3603 Comm: segctord Not tainted 6.1.0-rc2-syzkaller-00105-gb229b6ca5abb #0 Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022 RIP: 0010:nilfs_palloc_commit_free_entry+0xe5/0x6b0 fs/nilfs2/alloc.c:608 Code: 00 00 00 00 fc ff df 80 3c 02 00 0f 85 cd 05 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b 73 08 49 8d 7e 10 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 26 05 00 00 49 8b 46 10 be a6 00 00 00 48 c7 c7 RSP: 0018:ffffc90003dff830 EFLAGS: 00010212 RAX: dffffc0000000000 RBX: ffff88802594e218 RCX: 000000000000000d RDX: 0000000000000002 RSI: 0000000000002000 RDI: 0000000000000010 RBP: ffff888071880222 R08: 0000000000000005 R09: 000000000000003f R10: 000000000000000d R11: 0000000000000000 R12: ffff888071880158 R13: ffff88802594e220 R14: 0000000000000000 R15: 0000000000000004 FS: 0000000000000000(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb1c08316a8 CR3: 0000000018560000 CR4: 0000000000350ee0 Call Trace: nilfs_dat_commit_free fs/nilfs2/dat.c:114 [inline] nilfs_dat_commit_end+0x464/0x5f0 fs/nilfs2/dat.c:193 nilfs_dat_commit_update+0x26/0x40 fs/nilfs2/dat.c:236 nilfs_btree_commit_update_v+0x87/0x4a0 fs/nilfs2/btree.c:1940 nilfs_btree_commit_propagate_v fs/nilfs2/btree.c:2016 [inline] nilfs_btree_propagate_v fs/nilfs2/btree.c:2046 [inline] nilfs_btree_propagate+0xa00/0xd60 fs/nilfs2/btree.c:2088 nilfs_bmap_propagate+0x73/0x170 fs/nilfs2/bmap.c:337 nilfs_collect_file_data+0x45/0xd0 fs/nilfs2/segment.c:568 nilfs_segctor_apply_buffers+0x14a/0x470 fs/nilfs2/segment.c:1018 nilfs_segctor_scan_file+0x3f4/0x6f0 fs/nilfs2/segment.c:1067 nilfs_segctor_collect_blocks fs/nilfs2/segment.c:1197 [inline] nilfs_segctor_collect fs/nilfs2/segment.c:1503 [inline] nilfs_segctor_do_construct+0x12fc/0x6af0 fs/nilfs2/segment.c:2045 nilfs_segctor_construct+0x8e3/0xb30 fs/nilfs2/segment.c:2379 nilfs_segctor_thread_construct fs/nilfs2/segment.c:2487 [inline] nilfs_segctor_thread+0x3c3/0xf30 fs/nilfs2/segment.c:2570 kthread+0x2e4/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 ... If DAT metadata file is corrupted on disk, there is a case where req->pr_desc_bh is NULL and blocknr is 0 at nilfs_dat_commit_end() during a b-tree operation that cascadingly updates ancestor nodes of the b-tree, because nilfs_dat_commit_alloc() for a lower level block can initialize the blocknr on the same DAT entry between nilfs_dat_prepare_end() and nilfs_dat_commit_end(). If this happens, nilfs_dat_commit_end() calls nilfs_dat_commit_free() without valid buffer heads in req->pr_desc_bh and req->pr_bitmap_bh, and causes the NULL pointer dereference above in nilfs_palloc_commit_free_entry() function, which leads to a crash. Fix this by adding a NULL check on req->pr_desc_bh and req->pr_bitmap_bh before nilfs_palloc_commit_free_entry() in nilfs_dat_commit_free(). This also calls nilfs_error() in that case to notify that there is a fatal flaw in the filesystem metadata and prevent further operations. Link: https://lkml.kernel.org/r/00000000000097c20205ebaea3d6@google.com Link: https://lkml.kernel.org/r/20221114040441.1649940-1-zhangpeng362@huawei.com Link: https://lkml.kernel.org/r/20221119120542.17204-1-konishi.ryusuke@gmail.com Signed-off-by: ZhangPeng Signed-off-by: Ryusuke Konishi Reported-by: syzbot+ebe05ee8e98f755f61d0@syzkaller.appspotmail.com Tested-by: Ryusuke Konishi Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- fs/nilfs2/dat.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/fs/nilfs2/dat.c +++ b/fs/nilfs2/dat.c @@ -120,6 +120,13 @@ static void nilfs_dat_commit_free(struct kunmap_atomic(kaddr); nilfs_dat_commit_entry(dat, req); + + if (unlikely(req->pr_desc_bh == NULL || req->pr_bitmap_bh == NULL)) { + nilfs_error(dat->i_sb, + "state inconsistency probably due to duplicate use of vblocknr = %llu", + (unsigned long long)req->pr_entry_nr); + return; + } nilfs_palloc_commit_free_entry(dat, req); }