+ mm-vmpressurec-fix-race-in-vmpressure_work_fn.patch added to -mm tree

+ mm-vmpressurec-fix-race-in-vmpressure_work_fn.patch added to -mm tree

[akpm]

The patch titled
     Subject: mm/vmpressure.c: fix race in vmpressure_work_fn()
has been added to the -mm tree.  Its filename is
     mm-vmpressurec-fix-race-in-vmpressure_work_fn.patch

This patch should soon appear at
    http://ozlabs.org/~akpm/mmots/broken-out/mm-vmpressurec-fix-race-in-vmpressure_work_fn.patch
		echo and later at
		echo  http://ozlabs.org/~akpm/mmotm/broken-out/mm-vmpressurec-fix-race-in-vmpressure_work_fn.patch

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------------------------------------------------------
From: Andrew Morton <akpm@linux-foundation.org>
Subject: mm/vmpressure.c: fix race in vmpressure_work_fn()

In some android devices, there will be a "divide by zero" exception. 
vmpr->scanned could be zero before spin_lock(&vmpr->sr_lock).

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=88051

Reported-by: ji_ang <ji_ang@163.com>
Cc: Anton Vorontsov <anton.vorontsov@linaro.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/vmpressure.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff -puN mm/vmpressure.c~mm-vmpressurec-fix-race-in-vmpressure_work_fn mm/vmpressure.c
--- a/mm/vmpressure.c~mm-vmpressurec-fix-race-in-vmpressure_work_fn
+++ a/mm/vmpressure.c
@@ -165,6 +165,7 @@ static void vmpressure_work_fn(struct wo
 	unsigned long scanned;
 	unsigned long reclaimed;
 
+	spin_lock(&vmpr->sr_lock);
 	/*
 	 * Several contexts might be calling vmpressure(), so it is
 	 * possible that the work was rescheduled again before the old
@@ -173,10 +174,11 @@ static void vmpressure_work_fn(struct wo
 	 * here. No need for any locks here since we don't care if
 	 * vmpr->reclaimed is in sync.
 	 */
-	if (!vmpr->scanned)
+	if (!vmpr->scanned) {
+		spin_unlock(&vmpr->sr_lock);
 		return;
+	}
 
-	spin_lock(&vmpr->sr_lock);
 	scanned = vmpr->scanned;
 	reclaimed = vmpr->reclaimed;
 	vmpr->scanned = 0;
_

Patches currently in -mm which might be from akpm@linux-foundation.org are

i-need-old-gcc.patch
arch-alpha-kernel-systblss-remove-debug-check.patch
mm-vmpressurec-fix-race-in-vmpressure_work_fn.patch
input-route-kbd-leds-through-the-generic-leds-layer.patch
o2dlm-fix-null-pointer-dereference-in-o2dlm_blocking_ast_wrapper-checkpatch-fixes.patch
ocfs2-free-inode-when-i_count-becomes-zero.patch
ocfs2-add-functions-to-add-and-remove-inode-in-orphan-dir-fix.patch
mm.patch
slab-improve-checking-for-invalid-gfp_flags.patch
mm-memcontrol-lockless-page-counters-fix.patch
mm-memcontrol-lockless-page-counters-fix-fix.patch
kernel-res_counter-remove-the-unused-api-fix.patch
mm-compaction-simplify-deferred-compaction-fix.patch
mm-compaction-always-update-cached-scanner-positions-fix-checkpatch-fixes.patch
mm-memcontrol-remove-unnecessary-pcg_used-pc-mem_cgroup-valid-flag-fix.patch
mm-memcontrol-fold-mem_cgroup_start_move-mem_cgroup_end_move-fix.patch
mm-page_allocc-__alloc_pages_nodemask-dont-alter-arg-gfp_mask.patch
mm-mincore-add-hwpoison-page-handle-checkpatch-fixes.patch
mm-page_alloc-store-updated-page-migratetype-to-avoid-misusing-stale-value-fix.patch
mm-introduce-do_shared_fault-and-drop-do_fault-fix-fix.patch
zsmalloc-fix-zs_init-cpu-notifier-error-handling-fix-2.patch
zsmalloc-fix-zs_init-cpu-notifier-error-handling-fix.patch
do_shared_fault-check-that-mmap_sem-is-held.patch
fs-proc-use-a-rb-tree-for-the-directory-entries-fix.patch
fs-binfmt_miscc-use-gfp_kernel-instead-of-gfp_user.patch
init-allow-config_init_fallback=n-to-disable-defaults-if-init=-fails-checkpatch-fixes.patch
rtc-omap-add-support-for-pmic_power_en-v3-fix.patch
drivers-rtc-rtc-sirfsocc-add-alarm_irq_enable-support-fix.patch
exit-wait-cleanup-the-ptrace_reparented-checks-fix.patch
sysctl-terminate-strings-also-on-r-fix.patch
ipc-semc-chance-memory-barrier-in-sem_lock-to-smp_rmb-fix.patch
ipc-semc-chance-memory-barrier-in-sem_lock-to-smp_rmb-fix-fix.patch
ipc-msg-increase-msgmni-remove-scaling-checkpatch-fixes.patch
linux-next.patch
linux-next-rejects.patch
drivers-gpio-gpio-zevioc-fix-build.patch
mm-cma-make-kmemleak-ignore-cma-regions.patch
lib-show_mem-this-patch-adds-cma-reserved-infromation-fix.patch
tools-testing-selftests-makefile-alphasort-the-targets-list.patch
mm-replace-remap_file_pages-syscall-with-emulation.patch
debugging-keep-track-of-page-owners.patch
debugging-keep-track-of-page-owners-fix.patch
journal_add_journal_head-debug.patch
journal_add_journal_head-debug-fix.patch
kernel-forkc-export-kernel_thread-to-modules.patch
mutex-subsystem-synchro-test-module.patch
slab-leaks3-default-y.patch