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878b63ac88
linux/mm
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Hugh Dickins 878b63ac88 mm: gup persist for write permission 
do_wp_page()'s VM_FAULT_WRITE return value tells __get_user_pages() that
COW has been done if necessary, though it may be leaving the pte without
write permission - for the odd case of forced writing to a readonly vma
for ptrace.  At present GUP then retries the follow_page() without asking
for write permission, to escape an endless loop when forced.

But an application may be relying on GUP to guarantee a writable page
which won't be COWed again when written from userspace, whereas a race
here might leave a readonly pte in place?  Change the VM_FAULT_WRITE
handling to ask follow_page() for write permission again, except in that
odd case of forced writing to a readonly vma.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Robin Holt <holt@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-06 15:59:03 -08:00
..
allocpercpu.c mm/allocpercpu.c: make 4 functions static 2008-07-26 12:00:12 -07:00
backing-dev.c mm: change dirty limit type specifiers to unsigned long 2009-01-06 15:59:02 -08:00
bootmem.c misc: replace __FUNCTION__ with __func__ 2008-10-16 11:21:30 -07:00
bounce.c bounce: don't rely on a zeroed bio_vec list 2008-12-29 08:29:52 +01:00
dmapool.c
fadvise.c Remove Andrew Morton's old email accounts 2008-10-16 11:21:32 -07:00
failslab.c SLUB: failslab support 2008-12-29 11:27:46 +02:00
filemap_xip.c mm: xip/ext2 fix block allocation race 2008-08-20 15:40:32 -07:00
filemap.c mm: write_cache_pages integrity fix 2009-01-06 15:58:59 -08:00
fremap.c mmap: handle mlocked pages during map, remap, unmap 2008-10-20 08:52:31 -07:00
highmem.c x86, pat: avoid highmem cache attribute aliasing 2008-08-15 17:22:57 +02:00
hugetlb.c mm: report the MMU pagesize in /proc/pid/smaps 2009-01-06 15:58:58 -08:00
internal.h hugetlb: pull gigantic page initialisation out of the default path 2008-11-06 15:41:18 -08:00
Kconfig Unevictable LRU Infrastructure 2008-10-20 08:50:26 -07:00
maccess.c
madvise.c madvise: update function comment of madvise_dontneed 2008-07-30 09:41:45 -07:00
Makefile SLUB: failslab support 2008-12-29 11:27:46 +02:00
memcontrol.c memcg: fix page_cgroup allocation 2008-10-23 08:55:02 -07:00
memory_hotplug.c mm: remove GFP_HIGHUSER_PAGECACHE 2009-01-06 15:59:01 -08:00
memory.c mm: gup persist for write permission 2009-01-06 15:59:03 -08:00
mempolicy.c Merge branch 'master' into next 2008-11-14 11:29:12 +11:00
mempool.c
migrate.c mm: add Set,ClearPageSwapCache stubs 2009-01-06 15:59:02 -08:00
mincore.c
mlock.c x86, bts: memory accounting 2008-12-20 09:15:47 +01:00
mm_init.c mm: mminit_loglevel cannot be __meminitdata anymore 2008-08-20 15:40:30 -07:00
mmap.c mm: update my address 2009-01-05 17:44:42 -08:00
mmu_notifier.c mmu-notifiers: core 2008-07-28 16:30:21 -07:00
mmzone.c mm: mark the correct zone as full when scanning zonelists 2008-09-13 14:41:52 -07:00
mprotect.c mm: cleanup: remove #ifdef CONFIG_MIGRATION 2009-01-06 15:59:00 -08:00
mremap.c mm: update my address 2009-01-05 17:44:42 -08:00
msync.c add a vfs_fsync helper 2009-01-05 11:54:28 -05:00
nommu.c inode->i_op is never NULL 2009-01-05 11:54:28 -05:00
oom_kill.c oom: print triggering task's cpuset and mems allowed 2009-01-06 15:58:59 -08:00
page_alloc.c mm/page_alloc.c: eliminate NULL test and memset after alloc_bootmem 2009-01-06 15:59:02 -08:00
page_cgroup.c page_cgroup should ignore empty nodes 2008-12-10 08:01:53 -08:00
page_io.c mm: replace some BUG_ONs by VM_BUG_ONs 2009-01-06 15:59:02 -08:00
page_isolation.c memory hotplug: fix page_zone() calculation in test_pages_isolated() 2008-11-06 15:41:19 -08:00
page-writeback.c mm: add dirty_background_bytes and dirty_bytes sysctls 2009-01-06 15:59:03 -08:00
pagewalk.c
pdflush.c cpumask: convert mm/ 2009-01-01 10:12:29 +10:30
prio_tree.c
quicklist.c mm: size of quicklists shouldn't be proportional to the number of CPUs 2008-09-02 19:21:38 -07:00
readahead.c vmscan: split LRU lists into anon & file sets 2008-10-20 08:50:25 -07:00
rmap.c mm: further cleanup page_add_new_anon_rmap 2009-01-06 15:59:02 -08:00
shmem_acl.c [PATCH] sanitize ->permission() prototype 2008-07-26 20:53:14 -04:00
shmem.c mm: don't mark_page_accessed in shmem_fault 2009-01-06 15:58:58 -08:00
slab.c cpumask: convert mm/ 2009-01-01 10:12:29 +10:30
slob.c slob: do not pass the SLAB flags as GFP in kmem_cache_create() 2008-12-15 16:27:06 -08:00
slub.c cpumask: convert mm/ 2009-01-01 10:12:29 +10:30
sparse-vmemmap.c vmemmap: warn about page_structs with remote distance 2008-11-06 15:41:19 -08:00
sparse.c meminit section warnings 2008-11-30 10:03:35 -08:00
swap_state.c mm: replace some BUG_ONs by VM_BUG_ONs 2009-01-06 15:59:02 -08:00
swap.c mm: add_active_or_unevictable into rmap 2009-01-06 15:59:02 -08:00
swapfile.c mm: replace some BUG_ONs by VM_BUG_ONs 2009-01-06 15:59:02 -08:00
thrash.c
tiny-shmem.c Export tiny shmem_file_setup for DRM-GEM 2008-10-20 16:17:42 -07:00
truncate.c mmap: handle mlocked pages during map, remap, unmap 2008-10-20 08:52:31 -07:00
util.c mm: Make generic weak get_user_pages_fast and EXPORT_GPL it 2008-08-12 17:52:53 +10:00
vmalloc.c mm: vmalloc make lazy unmapping configurable 2009-01-06 15:59:01 -08:00
vmscan.c cpumask: convert mm/ 2009-01-01 10:12:29 +10:30
vmstat.c cpumask: convert mm/ 2009-01-01 10:12:29 +10:30