Return-Path: Received: from linuxhacker.ru ([217.76.32.60]:59034 "EHLO fiona.linuxhacker.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750889AbcFDQWR (ORCPT ); Sat, 4 Jun 2016 12:22:17 -0400 From: green@linuxhacker.ru To: Trond Myklebust , Anna Schumaker Cc: Olga Kornievskaia , linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org, Oleg Drokin Subject: [PATCH] nfs4: Fix potential use after free of state in nfs4_do_reclaim. Date: Sat, 4 Jun 2016 12:21:53 -0400 Message-Id: <1465057313-2582381-1-git-send-email-green@linuxhacker.ru> In-Reply-To: References: Sender: linux-nfs-owner@vger.kernel.org List-ID: From: Oleg Drokin Commit e8d975e73e5f ("fixing infinite OPEN loop in 4.0 stateid recovery") introduced access to state after it was just potentially freed by nfs4_put_open_state leading to a random data corruption somewhere. BUG: unable to handle kernel paging request at ffff88004941ee40 IP: [] nfs4_do_reclaim+0x461/0x740 PGD 3501067 PUD 3504067 PMD 6ff37067 PTE 800000004941e060 Oops: 0002 [#1] SMP DEBUG_PAGEALLOC Modules linked in: loop rpcsec_gss_krb5 acpi_cpufreq tpm_tis joydev i2c_piix4 pcspkr tpm virtio_console nfsd ttm drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops floppy serio_raw virtio_blk drm CPU: 6 PID: 2161 Comm: 192.168.10.253- Not tainted 4.7.0-rc1-vm-nfs+ #112 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 task: ffff8800463dcd00 ti: ffff88003ff48000 task.ti: ffff88003ff48000 RIP: 0010:[] [] nfs4_do_reclaim+0x461/0x740 RSP: 0018:ffff88003ff4bd68 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffffffff81a49900 RCX: 00000000000000e8 RDX: 00000000000000e8 RSI: ffff8800418b9930 RDI: ffff880040c96c88 RBP: ffff88003ff4bdf8 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff880040c96c98 R13: ffff88004941ee20 R14: ffff88004941ee40 R15: ffff88004941ee00 FS: 0000000000000000(0000) GS:ffff88006d000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff88004941ee40 CR3: 0000000060b0b000 CR4: 00000000000006e0 Stack: ffffffff813baad5 ffff8800463dcd00 ffff880000000001 ffffffff810e6b68 ffff880043ddbc88 ffff8800418b9800 ffff8800418b98c8 ffff88004941ee48 ffff880040c96c90 ffff880040c96c00 ffff880040c96c20 ffff880040c96c40 Call Trace: [] ? nfs4_do_reclaim+0x35/0x740 [] ? trace_hardirqs_on_caller+0x128/0x1b0 [] nfs4_run_state_manager+0x5ed/0xa40 [] ? nfs4_do_reclaim+0x740/0x740 [] ? nfs4_do_reclaim+0x740/0x740 [] kthread+0x101/0x120 [] ? trace_hardirqs_on_caller+0x128/0x1b0 [] ret_from_fork+0x1f/0x40 [] ? kthread_create_on_node+0x250/0x250 Code: 65 80 4c 8b b5 78 ff ff ff e8 fc 88 4c 00 48 8b 7d 88 e8 13 67 d2 ff 49 8b 47 40 a8 02 0f 84 d3 01 00 00 4c 89 ff e8 7f f9 ff ff 41 80 26 7f 48 8b 7d c8 e8 b1 84 4c 00 e9 39 fd ff ff 3d e6 RIP [] nfs4_do_reclaim+0x461/0x740 RSP CR2: ffff88004941ee40 Signed-off-by: Oleg Drokin --- fs/nfs/nfs4state.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c index 9679f47..834b875 100644 --- a/fs/nfs/nfs4state.c +++ b/fs/nfs/nfs4state.c @@ -1488,9 +1488,9 @@ restart: } spin_unlock(&state->state_lock); } - nfs4_put_open_state(state); clear_bit(NFS_STATE_RECLAIM_NOGRACE, &state->flags); + nfs4_put_open_state(state); spin_lock(&sp->so_lock); goto restart; } -- 2.5.5