Re: mmap() bug in 2.1.106

Andreas Schwab (schwab@issan.informatik.uni-dortmund.de)
24 Jun 1998 11:34:45 +0200


torvalds@transmeta.com (Linus Torvalds) writes:

|> In article <vyz1zslrbcq.fsf@issan.informatik.uni-dortmund.de>,
|> Andreas Schwab <schwab@issan.informatik.uni-dortmund.de> wrote:
|> >
|> >Here is a patch. The problem is that it faults in copy_from_user on the
|> >null pointer reference, and the fault handler wants to grap the mmap
|> >semaphore again -> deadlock.
|>
|> Don't apply this one. It changes one deadlock for another.
|>
|> We need to get the mm semaphore before we get the kernel lock. So you
|> have to move down both the "down()" _and_ the "lock_kernel()".

What about the down() in the fault handler? It will usually be executed
while the kernel lock is held. Or do i miss something?

Andreas.

-- 
Andreas Schwab                                      "And now for something
schwab@issan.informatik.uni-dortmund.de              completely different"
schwab@gnu.org

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