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SubjectRe: Sound driver security hole?
On Fri, 30 Jan 1998, Itai Nahshon wrote:

> Tom, I tried it and I would say it is not just a bug in the
> sound driver. Device close should be called only for the *last*
> close on the device. If a device or file is memory mapped
> it should still be open internally.

> IMHO this is a bug which is *not* related to the sound driver.

Not quite - you have to remember that mmap() is an operation applying to
the inode pointed to by the file descriptor, hence its existance well
after the fd is closed. If a device driver needs to hold onto resources
for the duration of an mmap()ing, then it should lock/unlock by providing
its own open and close functions in the vm_ops for the vma. Changing the
sound driver to obey the semantics of the mm layer might be a bit of a
pain, but it's the Right Thing(tm) to do.

-ben


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