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Re: Request for testers - socket locking diff

On Apr 13, 2008, at 10:17 AM, Andrew Doran wrote:
On Sat, Apr 12, 2008 at 10:41:18PM +0100, Andrew Doran wrote:

Here's an updated patch.

- Rudimentary tests on inet6 show it working.
- The bluetooth patch is merged in.
- More bugfixes, and assertions.
- The sbcheck change is bogus (sbcheck appears to be bogus, anyway)
- I think that I would prefer to move acquire of kernel_lock into the
  individual protocols, instead of always having the wrappers which
  will be unneeded baggage in the future.

One problem I know of: I think there is a race when sending SCM_RIGHTS
messages through a Unix socket. The symptom I see is gnome-terminal hanging due to a corrupted sockbuf. I think that the loop around unp_externalize in soreceive needs to be atomic. I'm surprised we never got bitten by this
before since it could block, but whatever.

Aside from the below I think the patch is nearly ready:

- Make protosw::pr_lock mandatory.

You mean pr_getlock?

- Make protocol methods take kernel_lock directly, and remove wrappers.
- Profiling and further testing.
- In netisrs, always lock in the socket -> kernel_lock direction, instead of letting the softint code take kernel_lock. This is just for efficiency.

Any comments on it?

In sys/unpcb.h, shouldn't unp_streamlock be kmutex_t * instead of void *?

sonewconn should have an extra param which is the kmutex_t * for the new
socket. Actually, I want two new params, the kmutex_t * and a void * for
initializing so_pcb but that's in the future.

pr_getlock() just seems wrong to me.  How hard is it going to be change
the so_lock of a socket?  (which would happen in PRU_ATTACH)?

I guess I think PRU_ATTACH should be called with so_lock NULL by default
and unlocked.

I don't you handle the case where head_so != so in the soq* routines.

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