Pavel Emelyanov e4a0d3e720 aio: Make it possible to remap aio ring ... There are actually two issues this patch addresses. Let me start with the one I tried to solve in the beginning. So, in the checkpoint-restore project (criu) we try to dump tasks' state and restore one back exactly as it was. One of the tasks' state bits is rings set up with io_setup() call. There's (almost) no problems in dumping them, there's a problem restoring them -- if I dump a task with aio ring originally mapped at address A, I want to restore one back at exactly the same address A. Unfortunately, the io_setup() does not allow for that -- it mmaps the ring at whatever place mm finds appropriate (it calls do_mmap_pgoff() with zero address and without the MAP_FIXED flag). To make restore possible I'm going to mremap() the freshly created ring into the address A (under which it was seen before dump). The problem is that the ring's virtual address is passed back to the user-space as the context ID and this ID is then used as search key by all the other io_foo() calls. Reworking this ID to be just some integer doesn't seem to work, as this value is already used by libaio as a pointer using which this library accesses memory for aio meta-data. So, to make restore work we need to make sure that a) ring is mapped at desired virtual address b) kioctx->user_id matches this value Having said that, the patch makes mremap() on aio region update the kioctx's user_id and mmap_base values. Here appears the 2nd issue I mentioned in the beginning of this mail. If (regardless of the C/R dances I do) someone creates an io context with io_setup(), then mremap()-s the ring and then destroys the context, the kill_ioctx() routine will call munmap() on wrong (old) address. This will result in a) aio ring remaining in memory and b) some other vma get unexpectedly unmapped. What do you think? Signed-off-by: Pavel Emelyanov <xemul@parallels.com> Acked-by: Dmitry Monakhov <dmonakhov@openvz.org> Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>		2014-12-13 17:49:50 -05:00
..
backing-dev.c	Merge branch 'for-3.18/core' of git://git.kernel.dk/linux-block	2014-10-18 11:53:51 -07:00
balloon_compaction.c	mm/balloon_compaction: fix deflation when compaction is disabled	2014-10-29 16:33:15 -07:00
bootmem.c	mem-hotplug: reset node managed pages when hot-adding a new pgdat	2014-11-13 16:17:06 -08:00
cleancache.c	mm: dump page when hitting a VM_BUG_ON using VM_BUG_ON_PAGE	2014-01-23 16:36:50 -08:00
cma.c	mm: cma: Use %pa to print physical addresses	2014-10-27 13:00:55 +01:00
compaction.c	mm, compaction: prevent infinite loop in compact_zone	2014-11-13 16:17:06 -08:00
debug-pagealloc.c
debug.c	mm/debug.c: use pr_emerg()	2014-10-09 22:25:59 -04:00
dmapool.c	mm/dmapool.c: fixed a brace coding style issue	2014-10-09 22:26:00 -04:00
early_ioremap.c	mm: create generic early_ioremap() support	2014-04-07 16:36:15 -07:00
fadvise.c	teach SYSCALL_DEFINE<n> how to deal with long long/unsigned long long	2013-03-03 22:46:22 -05:00
failslab.c
filemap_xip.c	seqcount: Add lockdep functionality to seqcount/seqlock structures	2013-11-06 12:40:26 +01:00
filemap.c	mm/filemap.c: remove trailing whitespace	2014-10-09 22:26:00 -04:00
fremap.c	mm: mark remap_file_pages() syscall as deprecated	2014-06-06 16:08:17 -07:00
frontswap.c	mm: frontswap: invalidate expired data on a dup-store failure	2014-12-02 17:32:07 -08:00
gup.c	mm: introduce a general RCU get_user_pages_fast()	2014-10-09 22:26:00 -04:00
highmem.c	mm/highmem: make kmap cache coloring aware	2014-08-06 18:01:22 -07:00
huge_memory.c	mm, thp: fix collapsing of hugepages on madvise	2014-10-29 16:33:14 -07:00
hugetlb_cgroup.c	hugetlb_cgroup: use lockdep_assert_held rather than spin_is_locked	2014-08-29 16:28:16 -07:00
hugetlb.c	mm: convert a few VM_BUG_ON callers to VM_BUG_ON_VMA	2014-10-09 22:25:57 -04:00
hwpoison-inject.c	mm/hwpoison-inject.c: remove unnecessary null test before debugfs_remove_recursive	2014-08-06 18:01:19 -07:00
init-mm.c
internal.h	mm/page_alloc: restrict max order of merging on isolated pageblock	2014-11-13 16:17:05 -08:00
interval_tree.c	mm: convert a few VM_BUG_ON callers to VM_BUG_ON_VMA	2014-10-09 22:25:57 -04:00
iov_iter.c	Fix thinko in iov_iter_single_seg_count	2014-11-13 13:28:55 -05:00
Kconfig	mm/balloon_compaction: add vmstat counters and kpageflags bit	2014-10-09 22:26:01 -04:00
Kconfig.debug	mm: more intensive memory corruption debugging	2012-01-10 16:30:42 -08:00
kmemcheck.c	mm/slab_common: move kmem_cache definition to internal header	2014-10-09 22:25:50 -04:00
kmemleak-test.c	mm/kmemleak-test.c: use pr_fmt for logging	2014-06-06 16:08:18 -07:00
kmemleak.c	mm: introduce kmemleak_update_trace()	2014-06-06 16:08:17 -07:00
ksm.c	mm: ksm use pr_err instead of printk	2014-10-09 22:26:00 -04:00
list_lru.c	mm: keep page cache radix tree nodes in check	2014-04-03 16:21:01 -07:00
maccess.c
madvise.c	mm: update the description for madvise_remove	2014-08-06 18:01:18 -07:00
Makefile	Fixup for 3.18: use PATCHv2 of "mm: Support compiling out madvise and fadvise"	2014-10-12 09:21:57 -04:00
memblock.c	mem-hotplug: let memblock skip the hotpluggable memory regions in __next_mem_range()	2014-09-10 15:42:12 -07:00
memcontrol.c	mm: memcontrol: fix missed end-writeback page accounting	2014-10-29 16:33:15 -07:00
memory_hotplug.c	mem-hotplug: reset node present pages when hot-adding a new pgdat	2014-11-13 16:17:06 -08:00
memory-failure.c	cgroup: remove redundant check in cgroup_ino()	2014-09-19 09:16:23 -04:00
memory.c	mm: fix swapoff hang after page migration and fork	2014-12-03 09:36:03 -08:00
mempolicy.c	mm: mempolicy: skip inaccessible VMAs when setting MPOL_MF_LAZY	2014-10-09 22:26:02 -04:00
mempool.c	mm/mempool.c: update the kmemleak stack trace for mempool allocations	2014-06-06 16:08:17 -07:00
migrate.c	mm/balloon_compaction: redesign ballooned pages management	2014-10-09 22:26:01 -04:00
mincore.c	mm + fs: prepare for non-page entries in page cache radix trees	2014-04-03 16:21:00 -07:00
mlock.c	Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2014-10-13 15:44:12 +02:00
mm_init.c	mm: bring back /sys/kernel/mm	2014-01-27 21:02:39 -08:00
mmap.c	mm: fix anon_vma_clone() error treatment	2014-12-03 09:36:04 -08:00
mmu_context.c	sched/mm: call finish_arch_post_lock_switch in idle_task_exit and use_mm	2014-02-21 08:50:17 +01:00
mmu_notifier.c	kvm: Fix page ageing bugs	2014-09-24 14:07:58 +02:00
mmzone.c	mm: numa: Change page last {nid,pid} into {cpu,pid}	2013-10-09 14:47:45 +02:00
mprotect.c	mm: softdirty: enable write notifications on VMAs after VM_SOFTDIRTY cleared	2014-10-14 02:18:28 +02:00
mremap.c	aio: Make it possible to remap aio ring	2014-12-13 17:49:50 -05:00
msync.c	msync: fix incorrect fstart calculation	2014-07-03 09:21:53 -07:00
nobootmem.c	mem-hotplug: reset node managed pages when hot-adding a new pgdat	2014-11-13 16:17:06 -08:00
nommu.c	percpu_counter: add @gfp to percpu_counter_init()	2014-09-08 09:51:29 +09:00
oom_kill.c	OOM, PM: OOM killed task shouldn't escape PM suspend	2014-10-21 23:44:21 +02:00
page_alloc.c	mm/debug-pagealloc: correct freepage accounting and order resetting	2014-11-13 16:17:06 -08:00
page_cgroup.c	cgroup/kmemleak: add kmemleak_free() for cgroup deallocations.	2014-10-29 16:33:13 -07:00
page_io.c	fix __swap_writepage() compile failure on old gcc versions	2014-06-14 19:30:48 -05:00
page_isolation.c	mm/page_alloc: restrict max order of merging on isolated pageblock	2014-11-13 16:17:05 -08:00
page-writeback.c	mm: memcontrol: fix missed end-writeback page accounting	2014-10-29 16:33:15 -07:00
pagewalk.c	mm: use VM_BUG_ON_MM where possible	2014-10-09 22:25:58 -04:00
percpu-km.c	percpu: implmeent pcpu_nr_empty_pop_pages and chunk->nr_populated	2014-09-02 14:46:05 -04:00
percpu-vm.c	percpu: move region iterations out of pcpu_[de]populate_chunk()	2014-09-02 14:46:02 -04:00
percpu.c	percpu: fix how @gfp is interpreted by the percpu allocator	2014-10-08 12:01:52 -04:00
pgtable-generic.c	mm: actually clear pmd_numa before invalidating	2014-08-29 16:28:15 -07:00
process_vm_access.c	start adding the tag to iov_iter	2014-05-06 17:32:49 -04:00
quicklist.c
readahead.c	mm/readahead.c: remove unused file_ra_state from count_history_pages	2014-08-06 18:01:15 -07:00
rmap.c	mm: fix anon_vma_clone() error treatment	2014-12-03 09:36:04 -08:00
shmem.c	shmem: support RENAME_WHITEOUT	2014-10-24 00:14:37 +02:00
slab_common.c	mm/slab: fix unalignment problem on Malta with EVA due to slab merge	2014-11-13 16:17:05 -08:00
slab.c	slab: fix nodeid bounds check for non-contiguous node IDs	2014-12-03 09:36:04 -08:00
slab.h	mm/slab: use percpu allocator for cpu cache	2014-10-09 22:25:51 -04:00
slob.c	mm/sl[ao]b: always track caller in kmalloc_(node_)track_caller()	2014-10-09 22:25:50 -04:00
slub.c	mm/slab_common: commonize slab merge logic	2014-10-09 22:25:51 -04:00
sparse-vmemmap.c	mm/sparse: use memblock apis for early memory allocations	2014-01-21 16:19:47 -08:00
sparse.c	mm: use macros from compiler.h instead of __attribute__((...))	2014-04-07 16:35:54 -07:00
swap_state.c	mm: memcontrol: do not kill uncharge batching in free_pages_and_swap_cache	2014-10-09 22:25:59 -04:00
swap.c	mm: memcontrol: do not kill uncharge batching in free_pages_and_swap_cache	2014-10-09 22:25:59 -04:00
swapfile.c	mm: memcontrol: rewrite uncharge API	2014-08-08 15:57:17 -07:00
truncate.c	mm: Fix comment before truncate_setsize()	2014-11-07 08:29:25 +11:00
util.c	proc/maps: make vm_is_stack() logic namespace-friendly	2014-10-09 22:25:50 -04:00
vmacache.c	mm,vmacache: optimize overflow system-wide flushing	2014-06-04 16:53:57 -07:00
vmalloc.c	mm/vmalloc.c: use seq_open_private() instead of seq_open()	2014-10-09 22:25:56 -04:00
vmpressure.c	mm/vmpressure.c: fix race in vmpressure_work_fn()	2014-12-02 17:32:07 -08:00
vmscan.c	mm: memcontrol: fix transparent huge page allocations under pressure	2014-10-09 22:25:59 -04:00
vmstat.c	vmstat: on-demand vmstat workers V8	2014-10-09 22:26:02 -04:00
workingset.c	mm: keep page cache radix tree nodes in check	2014-04-03 16:21:01 -07:00
zbud.c	zbud: avoid accessing last unused freelist	2014-10-09 22:26:03 -04:00
zpool.c	mm/zpool: use prefixed module loading	2014-08-29 16:28:16 -07:00
zsmalloc.c	zsmalloc: simplify init_zspage free obj linking	2014-10-09 22:26:03 -04:00
zswap.c	mm/zswap.c: add __init to zswap_entry_cache_destroy()	2014-08-08 15:57:18 -07:00