Messages in this thread | | | Date | Fri, 29 Mar 2013 16:16:01 -0700 | Subject | Re: ipc,sem: sysv semaphore scalability | From | Linus Torvalds <> |
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On Fri, Mar 29, 2013 at 2:12 PM, Linus Torvalds <torvalds@linux-foundation.org> wrote: > > I dunno. I'm still not sure this is triggerable, but it looks bad. But > both the semaphore case and the msg cases seem to be solvable by > moving the unlock down, and shm seem to have no getref/putref users to > race with, so this (whitespace-damaged) patch *may* be sufficient:
Well, the patch doesn't seem to cause any problems, at least neither lockdep nor spinlock sleep debugging complains. I have no idea whether it actually fixes any problems, though.
I do wonder if this might explain the problem Emmanuel saw. A double free of a RCU-freeable object would possibly result in exactly the kind of mess that Emmanuel reported with the semaphore scalability patches.
Emmanuel, can you try the attached patch? I think it applies cleanly on top of the scalability series too without any changes, but I didn't check if the patches perhaps changed some of the naming or something.
Linus [unhandled content-type:application/octet-stream] | |