Re: kernel crashes with btrfs and busy database IO - how to debug?

[Tomasz Chmielewski <tch@virtall.com>]

On 2015-06-14 09:30, Tomasz Chmielewski wrote:
> On 2015-06-13 08:23, Tomasz Chmielewski wrote:
> 
>> I did get it from /var/crash/ though - is it more useful? I don't have
>> vmlinux for this kernel though, but have just built 4.1-rc7 with the
>> same config, can try to get the crash there.
> 
> I've uploaded a crash dump and vmlinux here:
> 
> http://www.virtall.com/files/temp/201506132321/
> 
> Let me know if it's anything useful or if you need more info.

I've tried running it the same procedure to get one more crash, but it 
didn't crash this time.

Instead, btrfs is hanged on any writes - any processes trying to write 
get into D state and never return; there is no write activity when 
checking for example with iostat. "sync" command does not return.

Reads from this btrfs filesystem are OK.

I've uploaded the output of "echo w > /proc/sysrq-trigger" here:

http://www.virtall.com/files/temp/dmesg.txt


Tomasz Chmielewski