https://github.com/torvalds/linux
Revision aa9bca05a467c61dcea4142b2877d5392de5bdce authored by Weijie Yang on 16 October 2013, 20:46:54 UTC, committed by Linus Torvalds on 17 October 2013, 04:35:52 UTC
zswap_tree is not freed when swapoff, and it got re-kmalloced in swapon,
so a memory leak occurs.

Free the memory of zswap_tree in zswap_frontswap_invalidate_area().

Signed-off-by: Weijie Yang <weijie.yang@samsung.com>
Reviewed-by: Bob Liu <bob.liu@oracle.com>
Cc: Minchan Kim <minchan@kernel.org>
Reviewed-by: Minchan Kim <minchan@kernel.org>
Cc: <stable@vger.kernel.org>
From: Weijie Yang <weijie.yang@samsung.com>
Subject: mm/zswap: bugfix: memory leak when invalidate and reclaim occur concurrently

Consider the following scenario:
thread 0: reclaim entry x (get refcount, but not call zswap_get_swap_cache_page)
thread 1: call zswap_frontswap_invalidate_page to invalidate entry x.
	finished, entry x and its zbud is not freed as its refcount != 0
	now, the swap_map[x] = 0
thread 0: now call zswap_get_swap_cache_page
	swapcache_prepare return -ENOENT because entry x is not used any more
	zswap_get_swap_cache_page return ZSWAP_SWAPCACHE_NOMEM
	zswap_writeback_entry do nothing except put refcount
Now, the memory of zswap_entry x and its zpage leak.

Modify:
 - check the refcount in fail path, free memory if it is not referenced.

 - use ZSWAP_SWAPCACHE_FAIL instead of ZSWAP_SWAPCACHE_NOMEM as the fail path
   can be not only caused by nomem but also by invalidate.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Weijie Yang <weijie.yang@samsung.com>
Reviewed-by: Bob Liu <bob.liu@oracle.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: <stable@vger.kernel.org>
Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com>

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent e9cdd6e
History
Tip revision: aa9bca05a467c61dcea4142b2877d5392de5bdce authored by Weijie Yang on 16 October 2013, 20:46:54 UTC
mm/zswap: bugfix: memory leak when re-swapon
Tip revision: aa9bca0
File Mode Size
Kconfig -rw-r--r-- 18.7 KB
Kconfig.debug -rw-r--r-- 1015 bytes
Makefile -rw-r--r-- 2.0 KB
backing-dev.c -rw-r--r-- 16.5 KB
balloon_compaction.c -rw-r--r-- 9.6 KB
bootmem.c -rw-r--r-- 20.8 KB
bounce.c -rw-r--r-- 6.4 KB
cleancache.c -rw-r--r-- 12.7 KB
compaction.c -rw-r--r-- 32.5 KB
debug-pagealloc.c -rw-r--r-- 2.1 KB
dmapool.c -rw-r--r-- 13.1 KB
fadvise.c -rw-r--r-- 3.6 KB
failslab.c -rw-r--r-- 1.3 KB
filemap.c -rw-r--r-- 68.1 KB
filemap_xip.c -rw-r--r-- 11.3 KB
fremap.c -rw-r--r-- 6.7 KB
frontswap.c -rw-r--r-- 13.5 KB
highmem.c -rw-r--r-- 9.9 KB
huge_memory.c -rw-r--r-- 73.4 KB
hugetlb.c -rw-r--r-- 91.7 KB
hugetlb_cgroup.c -rw-r--r-- 10.4 KB
hwpoison-inject.c -rw-r--r-- 3.3 KB
init-mm.c -rw-r--r-- 619 bytes
internal.h -rw-r--r-- 11.2 KB
interval_tree.c -rw-r--r-- 3.2 KB
kmemcheck.c -rw-r--r-- 2.8 KB
kmemleak-test.c -rw-r--r-- 3.3 KB
kmemleak.c -rw-r--r-- 52.4 KB
ksm.c -rw-r--r-- 65.8 KB
list_lru.c -rw-r--r-- 3.1 KB
maccess.c -rw-r--r-- 1.6 KB
madvise.c -rw-r--r-- 14.2 KB
memblock.c -rw-r--r-- 30.1 KB
memcontrol.c -rw-r--r-- 187.7 KB
memory-failure.c -rw-r--r-- 45.8 KB
memory.c -rw-r--r-- 116.8 KB
memory_hotplug.c -rw-r--r-- 47.1 KB
mempolicy.c -rw-r--r-- 72.9 KB
mempool.c -rw-r--r-- 10.5 KB
migrate.c -rw-r--r-- 44.7 KB
mincore.c -rw-r--r-- 7.8 KB
mlock.c -rw-r--r-- 21.4 KB
mm_init.c -rw-r--r-- 5.0 KB
mmap.c -rw-r--r-- 85.9 KB
mmu_context.c -rw-r--r-- 1.2 KB
mmu_notifier.c -rw-r--r-- 9.5 KB
mmzone.c -rw-r--r-- 2.4 KB
mprotect.c -rw-r--r-- 10.3 KB
mremap.c -rw-r--r-- 14.9 KB
msync.c -rw-r--r-- 2.4 KB
nobootmem.c -rw-r--r-- 10.9 KB
nommu.c -rw-r--r-- 53.2 KB
oom_kill.c -rw-r--r-- 19.5 KB
page-writeback.c -rw-r--r-- 75.4 KB
page_alloc.c -rw-r--r-- 179.2 KB
page_cgroup.c -rw-r--r-- 11.9 KB
page_io.c -rw-r--r-- 8.9 KB
page_isolation.c -rw-r--r-- 7.5 KB
pagewalk.c -rw-r--r-- 5.9 KB
percpu-km.c -rw-r--r-- 2.8 KB
percpu-vm.c -rw-r--r-- 12.9 KB
percpu.c -rw-r--r-- 57.1 KB
pgtable-generic.c -rw-r--r-- 5.0 KB
process_vm_access.c -rw-r--r-- 13.2 KB
quicklist.c -rw-r--r-- 2.4 KB
readahead.c -rw-r--r-- 15.9 KB
rmap.c -rw-r--r-- 50.7 KB
shmem.c -rw-r--r-- 77.7 KB
slab.c -rw-r--r-- 114.2 KB
slab.h -rw-r--r-- 7.4 KB
slab_common.c -rw-r--r-- 15.4 KB
slob.c -rw-r--r-- 15.7 KB
slub.c -rw-r--r-- 125.4 KB
sparse-vmemmap.c -rw-r--r-- 5.9 KB
sparse.c -rw-r--r-- 21.0 KB
swap.c -rw-r--r-- 25.4 KB
swap_state.c -rw-r--r-- 11.4 KB
swapfile.c -rw-r--r-- 76.4 KB
truncate.c -rw-r--r-- 19.5 KB
util.c -rw-r--r-- 9.5 KB
vmalloc.c -rw-r--r-- 67.8 KB
vmpressure.c -rw-r--r-- 11.7 KB
vmscan.c -rw-r--r-- 106.8 KB
vmstat.c -rw-r--r-- 34.6 KB
zbud.c -rw-r--r-- 15.9 KB
zswap.c -rw-r--r-- 23.9 KB

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