Re: [libvirt] [PATCH 3/3] Remove wrong check for uml monitor response size

On 08/16/2010 03:54 AM, Soren Hansen wrote: > On Mon, Aug 16, 2010 at 11:37:07AM +0200, Soren Hansen wrote: >> I'm running this on another kernel right now and I'm not seeing the >> problem. I'll try again with the kernel I used a couple of days ago. > > Ok, found the other kernel. Same diff as in my previous e-mail, same > action. These are my results: > 09:41:01.134: debug : umlMonitorCommand:698 : Run command 'config con0' > 09:41:01.134: debug : umlMonitorCommand:733 : res.error: 6, res.extra: 0, res.length: 4096, res.data: > 09:41:01.134: debug : umlMonitorCommand:736 : nbytes: 0 > 09:41:01.134: debug : umlMonitorCommand:738 : res.error: 0, res.extra: 0, res.length: 4, res.data: pts > > This one's a 2.6.34.1 kernel. The one where I didn't see the problem is > a 2.6.32.something-or-the-other kernel. Mindboggling. Oh my. This really does look like a kernel bug. Can you confirm it with an strace? Have you reported this regression to the right kernel folks? I guess it would help if we could write a simpler test program to isolate whether this recvfrom bug exists in a bare minimum number of syscalls. Meanwhile, I have no idea how to work around a buggy recvfrom that doesn't return the correct number of bytes.