[Btrfs-devel] soft lockup during postmark

[Chris Mason]

On Monday 03 March 2008, Dongjun Shin wrote:
> Hello,
>
> I've found a soft lockup problem when running postmark on btrfs v0.13,
> kernel 2.6.24. The block size of btrfs is 4k.
>
> BUG: soft lockup - CPU#0 stuck for 11s! [postmark:3176]

Ouch, 11s isn't good  at all.
>
> Pid: 3176, comm: postmark Not tainted (2.6.24 #6)
> EIP: 0060:[<f8ced2a4>] EFLAGS: 00000287 CPU: 0
> EIP is at __alloc_extent_buffer+0x1a/0x87 [btrfs]
> EAX: f75e2980 EBX: f75e2a50 ECX: 00000001 EDX: c30d2098
> ESI: 005d4000 EDI: 00000000 EBP: c30d2078 ESP: f6692b44
>  DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
> CR0: 8005003b CR2: b7787004 CR3: 379c6000 CR4: 000006d0
> DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
> DR6: ffff0ff0 DR7: 00000400
>  [<f8cf1d47>] alloc_extent_buffer+0x72/0x2c7 [btrfs]

Fould you please look send me the disassembled output of alloc_extent_buffer 
for your kernel?  My guess is that you're actually in extent_io.c/find_lru, 
which would mean the lru list was corrupt.

Or, you're trying to get the spin lock.

>  [<f8cdc3a8>] btrfs_find_create_tree_block+0x2f/0x34 [btrfs]
>  [<f8cd9812>] __btrfs_alloc_free_block+0xec/0x2d8 [btrfs]
>  [<f8cd1d77>] split_leaf+0x1c5/0x7e8 [btrfs]
>  [<f8ccec74>] btrfs_leaf_free_space+0x36/0x77 [btrfs]
>  [<f8cd3baa>] btrfs_search_slot+0xe6c/0xeb7 [btrfs]
>  [<f8ce7eac>] btrfs_file_extent_num_bytes+0xb1/0xc1 [btrfs]
>  [<f8ce5c10>] btrfs_drop_extents+0xd1c/0xd38 [btrfs]
>  [<f8cd3c64>] btrfs_insert_empty_items+0x6f/0x3c6 [btrfs]
>  [<f8cede2e>] set_extent_bit+0x371/0x3c6 [btrfs]
>  [<f8cede2e>] set_extent_bit+0x371/0x3c6 [btrfs]
>  [<f8cdb1f6>] btrfs_insert_file_extent+0x6d/0x12d [btrfs]
>  [<f8ce64a1>] dirty_and_release_pages+0x2f9/0x5e6 [btrfs]
>  [<f8ce6e08>] btrfs_file_write+0x67a/0x806 [btrfs]
>  [<f8ce678e>] btrfs_file_write+0x0/0x806 [btrfs]
>  [<c046cce5>] vfs_write+0x8a/0x136
>  [<c046d2ee>] sys_write+0x41/0x67
>  [<c0404e52>] sysenter_past_esp+0x5f/0x91
>  =======================
>
> Is it better to post this kind of bug report to bugzilla at oss.oracle.com?

The list is best right now, thanks.

-chris