[Btrfs-devel] Oops

[Christian Hesse]

Hello everybody,

I've my Gentoo's /usr/portage on a loopback btrfs. Just wanted to sync and got 
an oops. I've a rsync and a ls process in status D now. The system has been 
in suspend (tuxonice 3.0-rc3) with mounted btrfs, perhaps that is related?

Dec  7 19:18:38 revo BUG: unable to handle kernel NULL pointer dereference at 
virtual address 0000000c
Dec  7 19:18:38 revo printing eip: b01dcd24 *pde = 00000000
Dec  7 19:18:38 revo Oops: 0000 [#1] SMP
Dec  7 19:18:38 revo Modules linked in: iwl3945 vboxdrv
Dec  7 19:18:38 revo
Dec  7 19:18:38 revo Pid: 9464, comm: rsync Not tainted (2.6.24-rc4 #1)
Dec  7 19:18:38 revo EIP: 0060:[<b01dcd24>] EFLAGS: 00210282 CPU: 0
Dec  7 19:18:38 revo EIP is at btrfs_set_key_blockptr+0x14/0x100
Dec  7 19:18:38 revo EAX: 00000000 EBX: 00000060 ECX: 10006000 EDX: 0000004f
Dec  7 19:18:38 revo ESI: 00000000 EDI: eb1293e4 EBP: eec7cbd4 ESP: c4d99c34
Dec  7 19:18:38 revo dhcpcd[8448]: wlan0: renewing lease of 192.168.182.74
Dec  7 19:18:38 revo DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
Dec  7 19:18:38 revo Process rsync (pid: 9464, ti=c4d98000 task=e0544ab0 
task.ti=c4d98000)
Dec  7 19:18:38 revo Stack: 00000000 eb1293e4 eec7c6f4 06040048 00000000 
20000000 000000dd 00000000
Dec  7 19:18:38 revo 00000000 00000000 00000000 eb1293e4 b01bf3e7 10006000 
00000000 00000000
Dec  7 19:18:38 revo 00000000 da25be70 ee8e1400 eec7c6f4 00000000 000001df 
00000000 eb1293e4
Dec  7 19:18:38 revo Call Trace:
Dec  7 19:18:38 revo [<b01bf3e7>] __btrfs_cow_block+0x1c7/0x390
Dec  7 19:18:38 revo [<b01bf726>] btrfs_cow_block+0x176/0x1a0
Dec  7 19:18:38 revo [<b01c1303>] btrfs_search_slot+0x103/0xe70
Dec  7 19:18:38 revo [<b02c5965>] dma_pool_alloc+0x155/0x1f0
Dec  7 19:18:38 revo [<b0121d7b>] enqueue_entity+0x2b/0x60
Dec  7 19:18:38 revo [<b0121dd7>] enqueue_task_fair+0x27/0x30
Dec  7 19:18:38 revo [<b0120b72>] enqueue_task+0x12/0x30
Dec  7 19:18:38 revo [<b0122d6e>] try_to_wake_up+0x4e/0x2b0
Dec  7 19:18:38 revo [<b01c9168>] btrfs_lookup_inode+0x38/0xc0
Dec  7 19:18:38 revo [<b01cd4c5>] btrfs_update_inode+0x45/0xc0
Dec  7 19:18:38 revo [<b01cf329>] btrfs_dirty_inode+0x49/0x80
Dec  7 19:18:38 revo [<b019e950>] __mark_inode_dirty+0x30/0x180
Dec  7 19:18:38 revo [<b0196197>] inode_setattr+0xb7/0x180
Dec  7 19:18:38 revo [<b01cee9e>] btrfs_setattr+0x3e/0x2a0
Dec  7 19:18:38 revo [<b01712e2>] handle_mm_fault+0xf2/0x570
Dec  7 19:18:38 revo [<b019633c>] notify_change+0xdc/0x2c0
Dec  7 19:18:38 revo [<b01a1611>] do_utimes+0x161/0x250
Dec  7 19:18:38 revo [<b01712e2>] handle_mm_fault+0xf2/0x570
Dec  7 19:18:38 revo [<b01a1721>] sys_futimesat+0x21/0xa0
Dec  7 19:18:38 revo [<b01a17bf>] sys_utimes+0x1f/0x30
Dec  7 19:18:38 revo [<b0104256>] sysenter_past_esp+0x5f/0x85
Dec  7 19:18:38 revo =======================
Dec  7 19:18:38 revo Code: 28 8b 74 24 2c 8b 7c 24 30 83 c4 34 c3 8d 76 00 8d 
bc 27 00 00 00 00 83 ec 30 89 5c 24 24 8d 5a 11 89 74 24 28 8
9 c6 89 7c 24 2c <8b> 78 0c 85 ff 74 45 8b 48 14 39 cb 72 3e 89 c8 83 c2 19 03 
46
Dec  7 19:18:38 revo EIP: [<b01dcd24>] btrfs_set_key_blockptr+0x14/0x100 
SS:ESP 0068:c4d99c34

Just wondering, is it safe to mount a btrfs root when a subvolume is already 
mounted?
-- 
Regards,
Chris