Johannes Weiner 28ccddf795 mm: memcg: remove incorrect VM_BUG_ON for swap cache pages in uncharge ... Commit 0c59b89c81 ("mm: memcg: push down PageSwapCache check into uncharge entry functions") added a VM_BUG_ON() on PageSwapCache in the uncharge path after checking that page flag once, assuming that the state is stable in all paths, but this is not the case and the condition triggers in user environments. An uncharge after the last page table reference to the page goes away can race with reclaim adding the page to swap cache. Swap cache pages are usually uncharged when they are freed after swapout, from a path that also handles swap usage accounting and memcg lifetime management. However, since the last page table reference is gone and thus no references to the swap slot left, the swap slot will be freed shortly when reclaim attempts to write the page to disk. The whole swap accounting is not even necessary. So while the race condition for which this VM_BUG_ON was added is real and actually existed all along, there are no negative effects. Remove the VM_BUG_ON again. Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com> Reported-by: Lingzhu Xiang <lxiang@redhat.com> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2013-05-24 16:22:51 -07:00
..
backing-dev.c	writeback: expose the bdi_wq workqueue	2013-04-01 19:08:06 -07:00
balloon_compaction.c	mm: introduce a common interface for balloon pages mobility	2012-12-11 17:22:26 -08:00
bootmem.c	mm: Add alloc_bootmem_low_pages_nopanic()	2013-01-29 19:32:59 -08:00
bounce.c	Merge branch 'for-3.10/core' of git://git.kernel.dk/linux-block	2013-05-08 10:13:35 -07:00
cleancache.c	mm: cleancache: clean up cleancache_enabled	2013-04-30 17:04:01 -07:00
compaction.c	mm: add & use zone_end_pfn() and zone_spans_pfn()	2013-02-23 17:50:20 -08:00
debug-pagealloc.c	mm, x86: Remove debug_pagealloc_enabled	2011-12-06 09:24:07 +01:00
dmapool.c	dmapool: make DMAPOOL_DEBUG detect corruption of free marker	2012-12-11 17:22:24 -08:00
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	switch debugfs to umode_t	2012-01-03 22:54:56 -05:00
filemap_xip.c	lift sb_start_write() out of ->write()	2013-04-09 14:12:56 -04:00
filemap.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2013-05-01 17:51:54 -07:00
fremap.c	Revert "mm: introduce VM_POPULATE flag to better deal with racy userspace programs"	2013-03-28 17:45:51 -07:00
frontswap.c	frontswap: get rid of swap_lock dependency	2013-04-30 17:04:00 -07:00
highmem.c	Some nice cleanups, and even a patch my wife did as a "live" demo for	2012-12-20 08:37:05 -08:00
huge_memory.c	thp: fix huge zero page logic for page with pfn == 0	2013-04-29 15:54:39 -07:00
hugetlb_cgroup.c	mm/hugetlb: create hugetlb cgroup file in hugetlb_init	2012-12-18 15:02:15 -08:00
hugetlb.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2013-04-30 09:36:50 -07:00
hwpoison-inject.c	memcg: rename config variables	2012-07-31 18:42:43 -07:00
init-mm.c	atomic: use <linux/atomic.h>	2011-07-26 16:49:47 -07:00
internal.h	mm: accelerate munlock() treatment of THP pages	2013-02-27 19:10:09 -08:00
interval_tree.c	mm: add CONFIG_DEBUG_VM_RB build option	2012-10-09 16:22:42 +09:00
Kconfig	mmKconfig: add an option to disable bounce	2013-04-29 15:54:40 -07:00
Kconfig.debug	mm: more intensive memory corruption debugging	2012-01-10 16:30:42 -08:00
kmemcheck.c
kmemleak-test.c	kmemleak: remove memset by using kzalloc	2011-01-27 18:31:51 +00:00
kmemleak.c	hlist: drop the node parameter from iterators	2013-02-27 19:10:24 -08:00
ksm.c	ksm: fix m68k build: only NUMA needs pfn_to_nid	2013-03-08 15:05:34 -08:00
maccess.c	mm: Map most files to use export.h instead of module.h	2011-10-31 09:20:12 -04:00
madvise.c	mm: madvise: complete input validation before taking lock	2013-04-29 15:54:37 -07:00
Makefile	memcg: add memory.pressure_level events	2013-04-29 15:54:38 -07:00
memblock.c	memblock: fix missing comment of memblock_insert_region()	2013-04-29 15:54:38 -07:00
memcontrol.c	mm: memcg: remove incorrect VM_BUG_ON for swap cache pages in uncharge	2013-05-24 16:22:51 -07:00
memory_hotplug.c	mm: fix memory_hotplug.c printk format warning	2013-04-29 15:54:39 -07:00
memory-failure.c	HWPOISON: check dirty flag to match against clean page	2013-04-29 15:54:28 -07:00
memory.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2013-04-30 09:36:50 -07:00
mempolicy.c	mm/mempolicy.c: fix sp_node_init() argument ordering	2013-03-08 15:05:34 -08:00
mempool.c	mempool: add @gfp_mask to mempool_create_node()	2012-06-25 11:53:47 +02:00
migrate.c	mm: rewrite the comment over migrate_pages() more comprehensibly	2013-04-29 15:54:37 -07:00
mincore.c	swap: make each swap partition have one address_space	2013-02-23 17:50:17 -08:00
mlock.c	Revert "mm: introduce VM_POPULATE flag to better deal with racy userspace programs"	2013-03-28 17:45:51 -07:00
mm_init.c	mm: init: report on last-nid information stored in page->flags	2013-02-23 17:50:18 -08:00
mmap.c	shm: fix null pointer deref when userspace specifies invalid hugepage size	2013-05-09 14:22:47 -07:00
mmu_context.c	mm: remove old aio use_mm() comment	2013-05-07 18:38:27 -07:00
mmu_notifier.c	mm: mmu_notifier: re-fix freed page still mapped in secondary MMU	2013-05-24 16:22:51 -07:00
mmzone.c	mm: rename page struct field helpers	2013-02-23 17:50:18 -08:00
mprotect.c	mm/mprotect.c: coding-style cleanups	2012-12-18 15:02:15 -08:00
mremap.c	mm/rmap: rename anon_vma_unlock() => anon_vma_unlock_write()	2013-02-23 17:50:17 -08:00
msync.c
nobootmem.c	mm, nobootmem: do memset() after memblock_reserve()	2013-04-29 15:54:39 -07:00
nommu.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal	2013-05-01 07:21:43 -07:00
oom_kill.c	memcg, oom: provide more precise dump info while memcg oom happening	2013-02-23 17:50:08 -08:00
page_alloc.c	mm: Fix virt_to_page() warning	2013-05-22 08:05:16 -07:00
page_cgroup.c	memcontrol: use N_MEMORY instead N_HIGH_MEMORY	2012-12-12 17:38:32 -08:00
page_io.c	Merge branch 'for-3.10/core' of git://git.kernel.dk/linux-block	2013-05-08 10:13:35 -07:00
page_isolation.c	mm: fix zone_watermark_ok_safe() accounting of isolated pages	2013-01-04 16:11:46 -08:00
page-writeback.c	mm: make snapshotting pages for stable writes a per-bio operation	2013-04-29 15:54:33 -07:00
pagewalk.c	thp: change split_huge_page_pmd() interface	2012-12-12 17:38:31 -08:00
percpu-km.c
percpu-vm.c	mm: fix kernel-doc warnings	2012-06-20 14:39:36 -07:00
percpu.c	mm, percpu: Make sure percpu_alloc early parameter has an argument	2012-12-02 06:23:04 -08:00
pgtable-generic.c	mm: Only flush the TLB when clearing an accessible pte	2012-12-11 14:28:34 +00:00
process_vm_access.c	Fix: compat_rw_copy_check_uvector() misuse in aio, readv, writev, and security keys	2013-03-12 11:05:45 -07:00
quicklist.c	mm: delete various needless include <linux/module.h>	2011-10-31 09:20:11 -04:00
readahead.c	teach SYSCALL_DEFINE<n> how to deal with long long/unsigned long long	2013-03-03 22:46:22 -05:00
rmap.c	rmap: recompute pgoff for unmapping huge page	2013-04-29 15:54:28 -07:00
shmem.c	aio: don't include aio.h in sched.h	2013-05-07 20:16:25 -07:00
slab_common.c	mm/slab: Fix crash during slab init	2013-05-08 15:02:33 -07:00
slab.c	Merge branch 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux	2013-05-07 08:42:20 -07:00
slab.h	slab: Common definition for kmem_cache_node	2013-02-01 12:32:09 +02:00
slob.c	mm: rename page struct field helpers	2013-02-23 17:50:18 -08:00
slub.c	Merge branch 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux	2013-05-07 08:42:20 -07:00
sparse-vmemmap.c	sparse-vmemmap: specify vmemmap population range in bytes	2013-04-29 15:54:35 -07:00
sparse.c	mm, hotplug: avoid compiling memory hotremove functions when disabled	2013-04-29 15:54:37 -07:00
swap_state.c	mm: thp: add split tail pages to shrink page list in page reclaim	2013-04-29 15:54:38 -07:00
swap.c	aio: don't include aio.h in sched.h	2013-05-07 20:16:25 -07:00
swapfile.c	frontswap: get rid of swap_lock dependency	2013-04-30 17:04:00 -07:00
truncate.c	mm: drop vmtruncate	2012-12-20 18:46:29 -05:00
util.c	swap: make each swap partition have one address_space	2013-02-23 17:50:17 -08:00
vmalloc.c	mm/vmalloc.c: add vfree comment	2013-05-07 18:38:27 -07:00
vmpressure.c	memcg: add memory.pressure_level events	2013-04-29 15:54:38 -07:00
vmscan.c	mm: thp: add split tail pages to shrink page list in page reclaim	2013-04-29 15:54:38 -07:00
vmstat.c	mm/vmstat: add note on safety of drain_zonestat	2013-04-29 15:54:38 -07:00