Messages in this thread | | | From | yodaiken@chelm ... | Date | Thu, 2 Apr 1998 11:47:26 -0700 | Subject | mmap oddness |
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mmap does not map /dev/mem or /dev/kmem correctly or I don't understand what it is supposed to do.
1. insmod a module that kmallocs a page and writes an identifier on the page and then printks the virt_to_phys and address. 2. a user task opens /dev/mem or /dev/kmem and reads every page looking for the identifier -- the identifier is found at exactly the expected position. 3. a user task opens /dev/mem or /dev/kmem and mmaps the page with the identifier -- no identifier found. 4. the task in (3) is modified to try every page in mem or kmem -- no identifier found. 5. If the kernel buffer is allocated statically, everything works as expected.
This is on 2.1.89, but is the same on a couple of other versions.
Explanations?
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