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Commit 0576da2c authored by Helge Deller's avatar Helge Deller
Browse files

parisc: fix mmap(MAP_FIXED|MAP_SHARED) to already mmapped address 



locale-gen on Debian showed a strange problem on parisc:
mmap2(NULL, 536870912, PROT_NONE, MAP_SHARED, 3, 0) = 0x42a54000
mmap2(0x42a54000, 103860, PROT_READ|PROT_WRITE, MAP_SHARED|MAP_FIXED, 3, 0) = -1 EINVAL (Invalid argument)

Basically it was just trying to re-mmap() a file at the same address
which it was given by a previous mmap() call. But this remapping failed
with EINVAL.

The problem is, that when MAP_FIXED and MAP_SHARED flags were used, we didn't
included the mapping-based offset when we verified the alignment of the given
fixed address against the offset which we calculated it in the previous call.

Signed-off-by: default avatarHelge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org> # 3.10+
parent dc1ccc48

arch/parisc/kernel/sys_parisc.c

+15 −10
Original line number Diff line number Diff line
@@ -61,8 +61,15 @@ static int get_offset(struct address_space *mapping) 
	return (unsigned long) mapping >> 8;

}



static unsigned long get_shared_area(struct address_space *mapping,

		unsigned long addr, unsigned long len, unsigned long pgoff)

static unsigned long shared_align_offset(struct file *filp, unsigned long pgoff)

{

	struct address_space *mapping = filp ? filp->f_mapping : NULL;



	return (get_offset(mapping) + pgoff) << PAGE_SHIFT;

}



static unsigned long get_shared_area(struct file *filp, unsigned long addr,

		unsigned long len, unsigned long pgoff)

{

	struct vm_unmapped_area_info info;
@@ -71,7 +78,7 @@ static unsigned long get_shared_area(struct address_space *mapping, 
	info.low_limit = PAGE_ALIGN(addr);

	info.high_limit = TASK_SIZE;

	info.align_mask = PAGE_MASK & (SHMLBA - 1);

	info.align_offset = (get_offset(mapping) + pgoff) << PAGE_SHIFT;

	info.align_offset = shared_align_offset(filp, pgoff);

	return vm_unmapped_area(&info);

}
@@ -82,20 +89,18 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, 
		return -ENOMEM;

	if (flags & MAP_FIXED) {

		if ((flags & MAP_SHARED) &&

		    (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))

		    (addr - shared_align_offset(filp, pgoff)) & (SHMLBA - 1))

			return -EINVAL;

		return addr;

	}

	if (!addr)

		addr = TASK_UNMAPPED_BASE;



	if (filp) {

		addr = get_shared_area(filp->f_mapping, addr, len, pgoff);

	} else if(flags & MAP_SHARED) {

		addr = get_shared_area(NULL, addr, len, pgoff);

	} else {

	if (filp || (flags & MAP_SHARED))

		addr = get_shared_area(filp, addr, len, pgoff);

	else

		addr = get_unshared_area(addr, len);

	}



	return addr;

}