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[PATCH] uclinux: fix mmap() of directory for nommu case

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I was playing with blackfin when i hit a neat bug ... doing an open() on a
directory and then passing that fd to mmap() would cause the kernel to hang

after poking into the code a bit more, i found that
mm/nommu.c:validate_mmap_request() checks the length and if it is 0, just
returns the address ... this is in stark contrast to mmu's
mm/mmap.c:do_mmap_pgoff() where it returns -EINVAL for 0 length requests ...
i then noticed that some other parts of the logic is out of date between the
two funcs, so perhaps that's the easy fix ?

Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Mike Frysinger 2006-12-06 12:02:59 +10:00 committed by Linus Torvalds
parent 3363c9b0ed
commit f81cff0d40
1 changed files with 7 additions and 5 deletions
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12
mm/nommu.c
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@ -497,15 +497,17 @@ static int validate_mmap_request(struct file *file,
(flags & MAP_TYPE) != MAP_SHARED)
return -EINVAL;
if (PAGE_ALIGN(len) == 0)
return addr;
if (len > TASK_SIZE)
if (!len)
return -EINVAL;
/* Careful about overflows.. */
len = PAGE_ALIGN(len);
if (!len || len > TASK_SIZE)
return -ENOMEM;
/* offset overflow? */
if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
return -EINVAL;
return -EOVERFLOW;
if (file) {
/* validate file mapping requests */