kernel_optimize_test/mm
Rafael Aquini cbab0e4eec swap: avoid read_swap_cache_async() race to deadlock while waiting on discard I/O completion
read_swap_cache_async() can race against get_swap_page(), and stumble
across a SWAP_HAS_CACHE entry in the swap map whose page wasn't brought
into the swapcache yet.

This transient swap_map state is expected to be transitory, but the
actual placement of discard at scan_swap_map() inserts a wait for I/O
completion thus making the thread at read_swap_cache_async() to loop
around its -EEXIST case, while the other end at get_swap_page() is
scheduled away at scan_swap_map().  This can leave the system deadlocked
if the I/O completion happens to be waiting on the CPU waitqueue where
read_swap_cache_async() is busy looping and !CONFIG_PREEMPT.

This patch introduces a cond_resched() call to make the aforementioned
read_swap_cache_async() busy loop condition to bail out when necessary,
thus avoiding the subtle race window.

Signed-off-by: Rafael Aquini <aquini@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-06-12 16:29:45 -07:00
..
backing-dev.c writeback: expose the bdi_wq workqueue 2013-04-01 19:08:06 -07:00
balloon_compaction.c
bootmem.c
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
debug-pagealloc.c
dmapool.c
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 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
huge_memory.c mm/THP: use pmd_populate() to update the pmd with pgtable_t pointer 2013-05-24 16:22:51 -07:00
hugetlb_cgroup.c
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
init-mm.c
internal.h mm: accelerate munlock() treatment of THP pages 2013-02-27 19:10:09 -08:00
interval_tree.c
Kconfig mmKconfig: add an option to disable bounce 2013-04-29 15:54:40 -07:00
Kconfig.debug
kmemcheck.c
kmemleak-test.c
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
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 memcg: don't initialize kmem-cache destroying work for root caches 2013-06-12 16:29:45 -07:00
memory_hotplug.c mm/memory_hotplug.c: fix printk format warnings 2013-05-24 16:22:52 -07:00
memory-failure.c HWPOISON: check dirty flag to match against clean page 2013-04-29 15:54:28 -07:00
memory.c arch, mm: Remove tlb_fast_mode() 2013-06-06 10:07:26 +09:00
mempolicy.c mm/mempolicy.c: fix sp_node_init() argument ordering 2013-03-08 15:05:34 -08:00
mempool.c
migrate.c mm compaction: fix of improper cache flush in migration code 2013-05-24 16:22:51 -07:00
mincore.c
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
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
mprotect.c
mremap.c
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
page_alloc.c mm: Fix virt_to_page() warning 2013-05-22 08:05:16 -07:00
page_cgroup.c
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
page-writeback.c mm: make snapshotting pages for stable writes a per-bio operation 2013-04-29 15:54:33 -07:00
pagewalk.c mm/pagewalk.c: walk_page_range should avoid VM_PFNMAP areas 2013-05-24 16:22:53 -07:00
percpu-km.c
percpu-vm.c
percpu.c
pgtable-generic.c
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
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
slob.c
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 swap: avoid read_swap_cache_async() race to deadlock while waiting on discard I/O completion 2013-06-12 16:29:45 -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
util.c
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