Alfred Perlstein <[EMAIL PROTECTED]> wrote:
> * Brian F. Feldman <[EMAIL PROTECTED]> [010424 05:07] wrote:
> > In some way, using Linux LinuxThreads programs that use shared memory, I've
> > ended up with dozens of shared memory segments that reportedly still have 1
> > attachment (which I'm really darn certain is impossible since I've killed
> > _everything_ in sight). I think something must have happened that for some
> > reason shmexit() was not called on process exit, vm_shm refcnt was increased
> > too many times, vm_shm refcnt was not decreased enough times... whatever the
> > case, there may be an old vmspace just floating around stranded, or just a
> > simple bug with vm_shm...
> >
> > Does anyone have any clues about races or weird issues in this area? It's
> > pretty exasperating to not be able to figure this one out. I don't
> > immediately see any obvious races after half an hour of searching (since it
> > appears all calls that can modify vmspace directly require Giant being held).
>
> sysv_shm registers atexit and atfork handlers, perhaps you can stick
> some debugging code in there?
BTW, it's easy enough to determine by a simple "cat /proc/*/map | grep
[addr]" on the %p address from shmsegs[].shm_internal->'s object reference
whether the segment is truly abandoned or not. I have a ton of these, which
are absolutely certainly abandoned:
m 15335469 0 --rwarwarwa green operator green operator 1 391168
37123 7674121:47:32 21:48:33 21:47:32
m 8060974 0 --rwarwarwa green operator green operator 1 483840
53214 7674122:16:44 22:17:46 22:16:44
m 4390959 0 --rwarwarwa green operator green operator 1 483840
53214 7674122:16:44 22:17:46 22:16:44
m 1441840 0 --rwarwarwa green operator green operator 1 483840
53214 7674122:16:44 22:17:46 22:16:44
etc.
Has anyone else at least experienced this? I'm happy it's not a memory
leak, but something definitely isn't calling shmexit() when it should be or
calling shmfork() when it shouldn't be.
--
Brian Fundakowski Feldman \ FreeBSD: The Power to Serve! /
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