Messages in this thread | | | From | "Stephen C. Tweedie" <> | Date | Mon, 11 Oct 1999 23:22:42 +0100 (BST) | Subject | Re: locking question: do_mmap(), do_munmap() |
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Hi,
On Mon, 11 Oct 1999 20:02:40 +0200, Manfred Spraul <manfreds@colorfullife.com> said:
> What about something like a rw-semaphore which protects the vma list: > vma-list modifiers [ie merge_segments(), insert_vm_struct() and > do_munmap()] grab it exclusive, swapper grabs it "shared, starve > exclusive".
Deadlock. Process A tries to do an mmap on mm A, gets the exclusive lock, tries to swap out from process B, and grabs mm B's shared lock. Process B in the mean time is doing the same thing and has an exclusive lock on mm B, and is trying to share-lock A. Whoops.
> This should not dead-lock,
Are you sure?!
--Stephen
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