Re: Data Corruption bug with Samba's vfs_iouring and Linux 5.6.7/5.7rc3

Jens Axboe
2020-05-05T15:44:40Z

On 5/5/20 8:41 AM, Jens Axboe wrote:
> On 5/5/20 4:04 AM, Stefan Metzmacher wrote:
>> Hi Jens,
>>
>> we currently have a bug report [1][2] regarding a data corruption with
>> Samba's vfs_io_uring.c [3].
>>
>> Is there're a know problem in newer kernels? It seems the 5.3 Kernel
>> doesn't have the problem (at least Jeremy wasn't able to reproduce it
>> on the Ubuntu 5.3 kernel).
>>
>> Do you have any hints how to track that down?
>
> I'll take a look at this! Any chance Jeremy can try 5.4 and 5.5 as well,
> just to see where we're at, roughly? That might be very helpful.

Trying to setup samba in a vm here to attempt to reproduce. I'm a major
samba noob, running with the smb.conf from the reporters email, I get:

[2020/05/05 15:43:07.126674, 0] ../../source4/smbd/server.c:629(binary_smbd_main)
samba version 4.12.2 started.
Copyright Andrew Tridgell and the Samba Team 1992-2020
[2020/05/05 15:43:07.152828, 0] ../../source4/smbd/server.c:826(binary_smbd_main)
At this time the 'samba' binary should only be used for either:
'server role = active directory domain controller' or to access the ntvfs file server with 'server services = +smb' or the rpc proxy with 'dcerpc endpoint servers = remote'
You should start smbd/nmbd/winbindd instead for domain member and standalone file server tasks
[2020/05/05 15:43:07.152937, 0] ../../lib/util/become_daemon.c:121(exit_daemon)
exit_daemon: daemon failed to start: Samba detected misconfigured 'server role' and exited. Check logs for details, error code 22

Clue bat appreciated.

--
Jens Axboe