linux/arch/powerpc/mm
Hugh Dickins 68589bc353 [PATCH] hugetlb: prepare_hugepage_range check offset too
(David:)

If hugetlbfs_file_mmap() returns a failure to do_mmap_pgoff() - for example,
because the given file offset is not hugepage aligned - then do_mmap_pgoff
will go to the unmap_and_free_vma backout path.

But at this stage the vma hasn't been marked as hugepage, and the backout path
will call unmap_region() on it.  That will eventually call down to the
non-hugepage version of unmap_page_range().  On ppc64, at least, that will
cause serious problems if there are any existing hugepage pagetable entries in
the vicinity - for example if there are any other hugepage mappings under the
same PUD.  unmap_page_range() will trigger a bad_pud() on the hugepage pud
entries.  I suspect this will also cause bad problems on ia64, though I don't
have a machine to test it on.

(Hugh:)

prepare_hugepage_range() should check file offset alignment when it checks
virtual address and length, to stop MAP_FIXED with a bad huge offset from
unmapping before it fails further down.  PowerPC should apply the same
prepare_hugepage_range alignment checks as ia64 and all the others do.

Then none of the alignment checks in hugetlbfs_file_mmap are required (nor
is the check for too small a mapping); but even so, move up setting of
VM_HUGETLB and add a comment to warn of what David Gibson discovered - if
hugetlbfs_file_mmap fails before setting it, do_mmap_pgoff's unmap_region
when unwinding from error will go the non-huge way, which may cause bad
behaviour on architectures (powerpc and ia64) which segregate their huge
mappings into a separate region of the address space.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Acked-by: Adam Litke <agl@us.ibm.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-11-14 09:09:27 -08:00
..
4xx_mmu.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
44x_mmu.c [POWERPC] Fix powerpc 44x_mmu build 2006-08-25 13:41:41 +10:00
Makefile [PATCH] powerpc: Some more fixes to allow building for a Book-E processor 2005-10-20 09:43:32 +10:00
fault.c [PATCH] pidspace: is_init() 2006-09-29 09:18:12 -07:00
fsl_booke_mmu.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
hash_low_32.S Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
hash_low_64.S Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
hash_native_64.c [POWERPC] powerpc: Initialise ppc_md htab pointers earlier 2006-06-28 11:59:47 +10:00
hash_utils_64.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
hugetlbpage.c [PATCH] hugetlb: prepare_hugepage_range check offset too 2006-11-14 09:09:27 -08:00
imalloc.c [PATCH] sem2mutex: misc static one-file mutexes 2006-03-26 08:56:55 -08:00
init_32.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
init_64.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
lmb.c [POWERPC] Fix mem= handling when the memory limit is > RMO size 2006-07-26 01:28:24 +10:00
mem.c [PATCH] mm: use symbolic names instead of indices for zone initialisation 2006-10-11 11:14:14 -07:00
mmap.c [PATCH] powerpc: trivial: modify comments to refer to new location of files 2006-02-10 16:53:51 +11:00
mmu_context_32.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
mmu_context_64.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
mmu_decl.h [PATCH] powerpc: Remove imalloc.h 2005-11-19 14:46:02 +11:00
numa.c [PATCH] mm: use symbolic names instead of indices for zone initialisation 2006-10-11 11:14:14 -07:00
pgtable_32.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
pgtable_64.c [POWERPC] fix ioremap for a combined kernel 2006-09-25 13:36:31 +10:00
ppc_mmu_32.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
slb.c [POWERPC] Implement SLB shadow buffer 2006-08-08 17:08:56 +10:00
slb_low.S [POWERPC] implement BEGIN/END_FW_FTR_SECTION 2006-10-03 16:50:21 +10:00
stab.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
tlb_32.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
tlb_64.c [POWERPC] Fix a compiler warning in mm/tlb_64.c 2006-07-13 18:43:25 +10:00