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:
[<ffffffff813204c0>] 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:[<ffffffff813204c0>] [<ffffffff813204c0>]
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]
[<ffffffff811e6d60>] inode_to_bdi+0x60/0x70
Aug 20 11:59:18 debian-build kernel: [ 325.172221]
[<ffffffff8114e232>] __filemap_fdatawrite_range+0x42/0x70
Aug 20 11:59:18 debian-build kernel: [ 325.172319]
[<ffffffff8114eea3>] filemap_fdatawrite_range+0x13/0x20
Aug 20 11:59:18 debian-build kernel: [ 325.172418]
[<ffffffffa0157c2b>] btrfs_fdatawrite_range+0x2b/0x70 [btrfs]
Aug 20 11:59:18 debian-build kernel: [ 325.172493]
[<ffffffffa015d57c>] btrfs_wait_ordered_range+0x4c/0x130 [btrfs]
Aug 20 11:59:18 debian-build kernel: [ 325.174258]
[<ffffffffa0155075>] ? btrfs_drop_extent_cache+0x355/0x420 [btrfs]
Aug 20 11:59:18 debian-build kernel: [ 325.175688]
[<ffffffffa014dde6>] btrfs_evict_inode+0x226/0x550 [btrfs]
Aug 20 11:59:18 debian-build kernel: [ 325.177252]
[<ffffffff811e726d>] ? __inode_wait_for_writeback+0x6d/0xc0
Aug 20 11:59:18 debian-build kernel: [ 325.179214]
[<ffffffff811d9058>] evict+0xb8/0x190
Aug 20 11:59:18 debian-build kernel: [ 325.180619]
[<ffffffff811d986b>] iput+0x18b/0x1f0
Aug 20 11:59:18 debian-build kernel: [ 325.182034]
[<ffffffff811d4f28>] __dentry_kill+0x198/0x200
Aug 20 11:59:18 debian-build kernel: [ 325.183559]
[<ffffffff811d50ad>] shrink_dentry_list+0x11d/0x2b0
Aug 20 11:59:18 debian-build kernel: [ 325.184981]
[<ffffffff811d56c8>] d_invalidate+0xd8/0x100
Aug 20 11:59:18 debian-build kernel: [ 325.186394]
[<ffffffffa017757b>] btrfs_ioctl_snap_destroy+0x50b/0x6e0 [btrfs]
Aug 20 11:59:18 debian-build kernel: [ 325.187832]
[<ffffffffa017abca>] btrfs_ioctl+0x131a/0x2a30 [btrfs]
Aug 20 11:59:18 debian-build kernel: [ 325.189239]
[<ffffffff8115ab2b>] ? lru_cache_add_active_or_unevictable+0x2b/0xa0
Aug 20 11:59:18 debian-build kernel: [ 325.190668]
[<ffffffff8117970a>] ? handle_mm_fault+0x2ba/0x1860
Aug 20 11:59:18 debian-build kernel: [ 325.192062]
[<ffffffff81181566>] ? mmap_region+0x316/0x630
Aug 20 11:59:18 debian-build kernel: [ 325.193453]
[<ffffffff81116ecc>] ? acct_account_cputime+0x1c/0x20
Aug 20 11:59:18 debian-build kernel: [ 325.194851]
[<ffffffff810ae3f9>] ? account_user_time+0x99/0xb0
Aug 20 11:59:18 debian-build kernel: [ 325.196241]
[<ffffffff811d0bd3>] do_vfs_ioctl+0x83/0x550
Aug 20 11:59:18 debian-build kernel: [ 325.197584]
[<ffffffff8114be23>] ? context_tracking_user_exit+0x13/0x20
Aug 20 11:59:18 debian-build kernel: [ 325.198913]
[<ffffffff81012558>] ? syscall_trace_enter_phase1+0xf8/0x160
Aug 20 11:59:18 debian-build kernel: [ 325.200229]
[<ffffffff811d10ec>] SyS_ioctl+0x4c/0x90
Aug 20 11:59:18 debian-build kernel: [ 325.201548]
[<ffffffff8163442e>] 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
[<ffffffff813204c0>] blk_get_backing_dev_info+0x10/0x20
Aug 20 11:59:18 debian-build kernel: [ 325.206983] RSP <ffff8800748e39a8>
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 <hch@xxxxxx>
| 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
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