linux/mm
Hugh Dickins 5fcf7bb73f [PATCH] read_zero_pagealigned() locking fix
Ramiro Voicu hits the BUG_ON(!pte_none(*pte)) in zeromap_pte_range: kernel
bugzilla 7645.  Right: read_zero_pagealigned uses down_read of mmap_sem,
but another thread's racing read of /dev/zero, or a normal fault, can
easily set that pte again, in between zap_page_range and zeromap_page_range
getting there.  It's been wrong ever since 2.4.3.

The simple fix is to use down_write instead, but that would serialize reads
of /dev/zero more than at present: perhaps some app would be badly
affected.  So instead let zeromap_page_range return the error instead of
BUG_ON, and read_zero_pagealigned break to the slower clear_user loop in
that case - there's no need to optimize for it.

Use -EEXIST for when a pte is found: BUG_ON in mmap_zero (the other user of
zeromap_page_range), though it really isn't interesting there.  And since
mmap_zero wants -EAGAIN for out-of-memory, the zeromaps better return that
than -ENOMEM.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: Ramiro Voicu: <Ramiro.Voicu@cern.ch>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-10 09:55:39 -08:00
..
allocpercpu.c [PATCH] Allow NULL pointers in percpu_free 2006-12-07 08:39:22 -08:00
backing-dev.c [PATCH] separate bdi congestion functions from queue congestion functions 2006-10-20 10:26:35 -07:00
bootmem.c [PATCH] remove EXPORT_UNUSED_SYMBOL'ed symbols 2006-12-07 08:39:44 -08:00
bounce.c [PATCH] BLOCK: Separate the bounce buffering code from the highmem code [try #6] 2006-09-30 20:32:11 +02:00
fadvise.c [PATCH] mm: change uses of f_{dentry,vfsmnt} to use f_path 2006-12-08 08:28:43 -08:00
filemap_xip.c [PATCH] mm: change uses of f_{dentry,vfsmnt} to use f_path 2006-12-08 08:28:43 -08:00
filemap.c [PATCH] mm: change uses of f_{dentry,vfsmnt} to use f_path 2006-12-08 08:28:43 -08:00
filemap.h Remove all inclusions of <linux/config.h> 2006-10-04 03:38:54 -04:00
fremap.c [PATCH] kill install_file_pte's pte_val 2006-12-07 08:39:23 -08:00
highmem.c [PATCH] BLOCK: Separate the bounce buffering code from the highmem code [try #6] 2006-09-30 20:32:11 +02:00
hugetlb.c [PATCH] mm: make compound page destructor handling explicit 2006-12-07 08:39:25 -08:00
internal.h [PATCH] mm: VM_BUG_ON 2006-09-26 08:48:44 -07:00
Kconfig Fix "can not" in Documentation and Kconfig 2006-10-03 22:53:09 +02:00
madvise.c [PATCH] Fix MADV_REMOVE protection checking 2006-04-17 18:22:18 -07:00
Makefile [PATCH] separate bdi congestion functions from queue congestion functions 2006-10-20 10:26:35 -07:00
memory_hotplug.c [PATCH] Get rid of zone_table[] 2006-12-07 08:39:20 -08:00
memory.c [PATCH] read_zero_pagealigned() locking fix 2006-12-10 09:55:39 -08:00
mempolicy.c [PATCH] struct path: convert mm 2006-12-08 08:28:47 -08:00
mempool.c [PATCH] dm: work around mempool_alloc, bio_alloc_bioset deadlocks 2006-09-01 11:39:09 -07:00
migrate.c [PATCH] radix-tree: RCU lockless readside 2006-12-07 08:39:25 -08:00
mincore.c [PATCH] freepgt: sys_mincore ignore FIRST_USER_PGD_NR 2005-04-19 13:29:20 -07:00
mlock.c [PATCH] mlock cleanup 2006-12-07 08:39:22 -08:00
mmap.c [PATCH] mm: change uses of f_{dentry,vfsmnt} to use f_path 2006-12-08 08:28:43 -08:00
mmzone.c [PATCH] remove EXPORT_UNUSED_SYMBOL'ed symbols 2006-12-07 08:39:44 -08:00
mprotect.c [PATCH] paravirt: lazy mmu mode hooks.patch 2006-10-01 00:39:33 -07:00
mremap.c [PATCH] paravirt: lazy mmu mode hooks.patch 2006-10-01 00:39:33 -07:00
msync.c [PATCH] mm: msync() cleanup 2006-09-26 08:48:45 -07:00
nommu.c [PATCH] struct path: convert mm 2006-12-08 08:28:47 -08:00
oom_kill.c [PATCH] oom: less memdie 2006-12-07 08:39:20 -08:00
page_alloc.c [PATCH] fault-injection: defaults likely to please a new user 2006-12-08 08:29:03 -08:00
page_io.c [PATCH] swsusp: use block device offsets to identify swap locations 2006-12-07 08:39:27 -08:00
page-writeback.c [PATCH] separate bdi congestion functions from queue congestion functions 2006-10-20 10:26:35 -07:00
pdflush.c [PATCH] Add include/linux/freezer.h and move definitions from sched.h 2006-12-07 08:39:27 -08:00
prio_tree.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
readahead.c [PATCH] struct path: convert mm 2006-12-08 08:28:47 -08:00
rmap.c [PATCH] mm: more commenting on lock ordering 2006-10-20 10:26:44 -07:00
shmem_acl.c [PATCH] Fix typos in mm/shmem_acl.c 2006-10-11 11:14:23 -07:00
shmem.c [PATCH] mm: change uses of f_{dentry,vfsmnt} to use f_path 2006-12-08 08:28:43 -08:00
slab.c [PATCH] fault-injection: defaults likely to please a new user 2006-12-08 08:29:03 -08:00
slob.c [PATCH] Make kmem_cache_destroy() return void 2006-09-27 08:26:11 -07:00
sparse.c [PATCH] numa node ids are int, page_to_nid and zone_to_nid should return int 2006-12-07 08:39:23 -08:00
swap_state.c [PATCH] lockdep: locking init debugging improvement 2006-07-03 15:27:02 -07:00
swap.c [PATCH] hotplug CPU: clean up hotcpu_notifier() use 2006-12-07 08:39:39 -08:00
swapfile.c [PATCH] mm: change uses of f_{dentry,vfsmnt} to use f_path 2006-12-08 08:28:43 -08:00
thrash.c [PATCH] make mm/thrash.c:global_faults static 2006-12-07 08:39:22 -08:00
tiny-shmem.c [PATCH] struct path: convert mm 2006-12-08 08:28:47 -08:00
truncate.c [PATCH] invalidate: remove_mapping() fix 2006-10-17 08:18:43 -07:00
util.c [PATCH] slab: clean up leak tracking ifdefs a little bit 2006-10-04 07:55:13 -07:00
vmalloc.c [PATCH] Fix strange size check in __get_vm_area_node() 2006-11-16 11:43:38 -08:00
vmscan.c [PATCH] hotplug CPU: clean up hotcpu_notifier() use 2006-12-07 08:39:39 -08:00
vmstat.c [PATCH] struct seq_operations and struct file_operations constification 2006-12-07 08:39:46 -08:00