From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ph.de-nserver.de ([85.158.179.214]:31929 "EHLO mail-ph.de-nserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753443AbbHVR36 (ORCPT ); Sat, 22 Aug 2015 13:29:58 -0400 To: "linux-btrfs@vger.kernel.org" , linux-fsdevel@vger.kernel.org From: Stefan Priebe Subject: btrfs regression since 4.X kernel NULL pointer dereference Cc: Christoph Hellwig Message-ID: <55D8B193.8010906@profihost.ag> Date: Sat, 22 Aug 2015 19:29:55 +0200 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: Hello, today i experienced the following btrfs bug: Aug 20 11:59:18 debian-build kernel: [ 325.170036] BUG: unable to handle kernel NULL pointer dereference at 0000000000000330 Aug 20 11:59:18 debian-build kernel: [ 325.170144] IP: [] blk_get_backing_dev_info+0x10/0x20 Aug 20 11:59:18 debian-build kernel: [ 325.170216] PGD 74f57067 PUD 74f51067 PMD 0 Aug 20 11:59:18 debian-build kernel: [ 325.170282] Oops: 0000 [#1] SMP Aug 20 11:59:18 debian-build kernel: [ 325.170330] Modules linked in: dm_mod netconsole xt_multiport iptable_filter ip_tables x_tab les cpufreq_userspace cpufreq_stats cpufreq_powersave cpufreq_conservative ext2 loop shpchp i2c_piix4 i2c_core virtio_balloon acpi_c pufreq button btrfs xor lzo_compress usbhid raid6_pq ata_generic sg sd_mod virtio_net virtio_scsi floppy uhci_hcd ehci_hcd ata_piix usbcore usb_common virtio_pci Aug 20 11:59:18 debian-build kernel: [ 325.170783] CPU: 4 PID: 13323 Comm: btrfs Not tainted 4.1.6+17-ph #1 Aug 20 11:59:18 debian-build kernel: [ 325.170842] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.8.1-0-g4adadbd-20150316_085822-nilsson.home.kraxel.org 04/01/2014 Aug 20 11:59:18 debian-build kernel: [ 325.170952] task: ffff88022d6bbae0 ti: ffff8800748e0000 task.ti: ffff8800748e0000 Aug 20 11:59:18 debian-build kernel: [ 325.171017] RIP: 0010:[] [] blk_get_backing_dev_info+0x10/0x20 Aug 20 11:59:18 debian-build kernel: [ 325.171096] RSP: 0018:ffff8800748e39a8 EFLAGS: 00010202 Aug 20 11:59:18 debian-build kernel: [ 325.171148] RAX: 0000000000000000 RBX: ffff880234680770 RCX: 0000000000000001 Aug 20 11:59:18 debian-build kernel: [ 325.171210] RDX: 7fffffffffffffff RSI: 0000000000000000 RDI: ffff880234680680 Aug 20 11:59:18 debian-build kernel: [ 325.171271] RBP: ffff8800748e39a8 R08: 7fffffffffffffff R09: 0000000000000246 Aug 20 11:59:18 debian-build kernel: [ 325.171333] R10: ffffffffa0158bdc R11: 0000000000000000 R12: ffff880237019000 Aug 20 11:59:18 debian-build kernel: [ 325.171393] R13: 7fffffffffffffff R14: ffff880092df07fc R15: 7fffffffffffffff Aug 20 11:59:18 debian-build kernel: [ 325.171455] FS: 00007fb05f0ba880(0000) GS:ffff88023fd00000(0000) knlGS:0000000000000000 Aug 20 11:59:18 debian-build kernel: [ 325.171522] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 Aug 20 11:59:18 debian-build kernel: [ 325.171577] CR2: 0000000000000330 CR3: 0000000074ce4000 CR4: 00000000000006e0 Aug 20 11:59:18 debian-build kernel: [ 325.171669] Stack: Aug 20 11:59:18 debian-build kernel: [ 325.171706] ffff8800748e39c8 ffffffff811e6d60 ffff8802346808c0 0000000000000000 Aug 20 11:59:18 debian-build kernel: [ 325.171811] ffff8800748e3a18 ffffffff8114e232 ffff880212f93910 7fffffffffffffff Aug 20 11:59:18 debian-build kernel: [ 325.171923] 0000000000000000 0000000000000000 7fffffffffffffff 0000000000000001 Aug 20 11:59:18 debian-build kernel: [ 325.172078] Call Trace: Aug 20 11:59:18 debian-build kernel: [ 325.172132] [] inode_to_bdi+0x60/0x70 Aug 20 11:59:18 debian-build kernel: [ 325.172221] [] __filemap_fdatawrite_range+0x42/0x70 Aug 20 11:59:18 debian-build kernel: [ 325.172319] [] filemap_fdatawrite_range+0x13/0x20 Aug 20 11:59:18 debian-build kernel: [ 325.172418] [] btrfs_fdatawrite_range+0x2b/0x70 [btrfs] Aug 20 11:59:18 debian-build kernel: [ 325.172493] [] btrfs_wait_ordered_range+0x4c/0x130 [btrfs] Aug 20 11:59:18 debian-build kernel: [ 325.174258] [] ? btrfs_drop_extent_cache+0x355/0x420 [btrfs] Aug 20 11:59:18 debian-build kernel: [ 325.175688] [] btrfs_evict_inode+0x226/0x550 [btrfs] Aug 20 11:59:18 debian-build kernel: [ 325.177252] [] ? __inode_wait_for_writeback+0x6d/0xc0 Aug 20 11:59:18 debian-build kernel: [ 325.179214] [] evict+0xb8/0x190 Aug 20 11:59:18 debian-build kernel: [ 325.180619] [] iput+0x18b/0x1f0 Aug 20 11:59:18 debian-build kernel: [ 325.182034] [] __dentry_kill+0x198/0x200 Aug 20 11:59:18 debian-build kernel: [ 325.183559] [] shrink_dentry_list+0x11d/0x2b0 Aug 20 11:59:18 debian-build kernel: [ 325.184981] [] d_invalidate+0xd8/0x100 Aug 20 11:59:18 debian-build kernel: [ 325.186394] [] btrfs_ioctl_snap_destroy+0x50b/0x6e0 [btrfs] Aug 20 11:59:18 debian-build kernel: [ 325.187832] [] btrfs_ioctl+0x131a/0x2a30 [btrfs] Aug 20 11:59:18 debian-build kernel: [ 325.189239] [] ? lru_cache_add_active_or_unevictable+0x2b/0xa0 Aug 20 11:59:18 debian-build kernel: [ 325.190668] [] ? handle_mm_fault+0x2ba/0x1860 Aug 20 11:59:18 debian-build kernel: [ 325.192062] [] ? mmap_region+0x316/0x630 Aug 20 11:59:18 debian-build kernel: [ 325.193453] [] ? acct_account_cputime+0x1c/0x20 Aug 20 11:59:18 debian-build kernel: [ 325.194851] [] ? account_user_time+0x99/0xb0 Aug 20 11:59:18 debian-build kernel: [ 325.196241] [] do_vfs_ioctl+0x83/0x550 Aug 20 11:59:18 debian-build kernel: [ 325.197584] [] ? context_tracking_user_exit+0x13/0x20 Aug 20 11:59:18 debian-build kernel: [ 325.198913] [] ? syscall_trace_enter_phase1+0xf8/0x160 Aug 20 11:59:18 debian-build kernel: [ 325.200229] [] SyS_ioctl+0x4c/0x90 Aug 20 11:59:18 debian-build kernel: [ 325.201548] [] system_call_fastpath+0x12/0x71 Aug 20 11:59:18 debian-build kernel: [ 325.202836] Code: e9 23 ff ff ff b8 01 00 00 00 45 31 e4 eb d5 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 44 00 00 48 8b 87 98 00 00 00 55 48 89 e5 <48> 8b 80 30 03 00 00 5d 48 05 98 01 00 00 c3 90 0f 1f 44 00 00 Aug 20 11:59:18 debian-build kernel: [ 325.205694] RIP [] blk_get_backing_dev_info+0x10/0x20 Aug 20 11:59:18 debian-build kernel: [ 325.206983] RSP Aug 20 11:59:18 debian-build kernel: [ 325.208233] CR2: 0000000000000330 Aug 20 11:59:18 debian-build kernel: [ 325.209467] ---[ end trace 9dd28134a31aacc4 ]--- It was introduced by: | commit de1414a654e66b81b5348dbc5259ecf2fb61655e | Author: Christoph Hellwig | Date: Wed Jan 14 10:42:36 2015 +0100 | | fs: export inode_to_bdi and use it in favor of mapping->backing_dev_info More details and a reproducer from a 3rd person can be found here: https://bugzilla.kernel.org/show_bug.cgi?id=100911 Greets, Stefan