The patch titled
Subject: mm: fix build warning for uninitialized value
has been added to the -mm tree. Its filename is
mm-fix-build-warning-for-uninitialized-value.patch
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------------------------------------------------------
From: David Rientjes <rientjes@xxxxxxxxxx>
Subject: mm: fix build warning for uninitialized value
do_wp_page() sets mmun_called if mmun_start and mmun_end were initialized
and, if so, may call mmu_notifier_invalidate_range_end() with these
values. This doesn't prevent gcc from emitting a build warning though:
mm/memory.c: In function `do_wp_page':
mm/memory.c:2530: warning: `mmun_start' may be used uninitialized in this function
mm/memory.c:2531: warning: `mmun_end' may be used uninitialized in this function
It's much easier to initialize the variables to impossible values and do a
simple comparison to determine if they were initialized to remove the bool
entirely.
Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
diff -puN mm/memory.c~mm-fix-build-warning-for-uninitialized-value mm/memory.c
--- a/mm/memory.c~mm-fix-build-warning-for-uninitialized-value
+++ a/mm/memory.c
@@ -2572,9 +2572,8 @@ static int do_wp_page(struct mm_struct *
int ret = 0;
int page_mkwrite = 0;
struct page *dirty_page = NULL;
- unsigned long mmun_start; /* For mmu_notifiers */
- unsigned long mmun_end; /* For mmu_notifiers */
- bool mmun_called = false; /* For mmu_notifiers */
+ unsigned long mmun_start = 0; /* For mmu_notifiers */
+ unsigned long mmun_end = 0; /* For mmu_notifiers */
old_page = vm_normal_page(vma, address, orig_pte);
if (!old_page) {
@@ -2753,8 +2752,7 @@ gotten:
goto oom_free_new;
mmun_start = address & PAGE_MASK;
- mmun_end = (address & PAGE_MASK) + PAGE_SIZE;
- mmun_called = true;
+ mmun_end = mmun_start + PAGE_SIZE;
mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
/*
@@ -2823,7 +2821,7 @@ gotten:
page_cache_release(new_page);
unlock:
pte_unmap_unlock(page_table, ptl);
- if (mmun_called)
+ if (mmun_end > mmun_start)
mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
if (old_page) {
/*
_
Patches currently in -mm which might be from rientjes@xxxxxxxxxx are
mm-bugfix-set-current-reclaim_state-to-null-while-returning-from-kswapd.patch
linux-next.patch
mm-fix-build-warning-for-uninitialized-value.patch
mm-memcg-make-mem_cgroup_out_of_memory-static.patch
mm-use-is_enabledconfig_numa-instead-of-numa_build.patch
mm-use-is_enabledconfig_compaction-instead-of-compaction_build.patch
thp-clean-up-__collapse_huge_page_isolate.patch
memory-hotplug-suppress-device-memoryx-does-not-have-a-release-function-warning.patch
memory-hotplug-skip-hwpoisoned-page-when-offlining-pages.patch
memory-hotplug-update-mce_bad_pages-when-removing-the-memory.patch
memory-hotplug-update-mce_bad_pages-when-removing-the-memory-fix.patch
memory-hotplug-auto-offline-page_cgroup-when-onlining-memory-block-failed.patch
memory-hotplug-fix-nr_free_pages-mismatch.patch
numa-convert-static-memory-to-dynamically-allocated-memory-for-per-node-device.patch
memory-hotplug-suppress-device-nodex-does-not-have-a-release-function-warning.patch
memory-hotplug-mm-sparsec-clear-the-memory-to-store-struct-page.patch
memory-hotplug-allocate-zones-pcp-before-onlining-pages.patch
memory-hotplug-allocate-zones-pcp-before-onlining-pages-fix.patch
memory-hotplug-allocate-zones-pcp-before-onlining-pages-fix-2.patch
memory_hotplug-fix-possible-incorrect-node_states.patch
slub-hotplug-ignore-unrelated-nodes-hot-adding-and-hot-removing.patch
mm-oom-allow-exiting-threads-to-have-access-to-memory-reserves.patch
memcg-make-it-possible-to-use-the-stock-for-more-than-one-page.patch
memcg-reclaim-when-more-than-one-page-needed.patch
memcg-change-defines-to-an-enum.patch
memcg-kmem-accounting-basic-infrastructure.patch
mm-add-a-__gfp_kmemcg-flag.patch
memcg-kmem-controller-infrastructure.patch
mm-allocate-kernel-pages-to-the-right-memcg.patch
res_counter-return-amount-of-charges-after-res_counter_uncharge.patch
memcg-kmem-accounting-lifecycle-management.patch
memcg-use-static-branches-when-code-not-in-use.patch
memcg-allow-a-memcg-with-kmem-charges-to-be-destructed.patch
memcg-execute-the-whole-memcg-freeing-in-free_worker.patch
fork-protect-architectures-where-thread_size-=-page_size-against-fork-bombs.patch
memcg-add-documentation-about-the-kmem-controller.patch
slab-slub-struct-memcg_params.patch
slab-annotate-on-slab-caches-nodelist-locks.patch
slab-slub-consider-a-memcg-parameter-in-kmem_create_cache.patch
memcg-allocate-memory-for-memcg-caches-whenever-a-new-memcg-appears.patch
memcg-infrastructure-to-match-an-allocation-to-the-right-cache.patch
memcg-skip-memcg-kmem-allocations-in-specified-code-regions.patch
slb-always-get-the-cache-from-its-page-in-kmem_cache_free.patch
slb-allocate-objects-from-memcg-cache.patch
memcg-destroy-memcg-caches.patch
memcg-slb-track-all-the-memcg-children-of-a-kmem_cache.patch
memcg-slb-shrink-dead-caches.patch
memcg-aggregate-memcg-cache-values-in-slabinfo.patch
slab-propagate-tunable-values.patch
slub-slub-specific-propagation-changes.patch
slub-slub-specific-propagation-changes-fix.patch
kmem-add-slab-specific-documentation-about-the-kmem-controller.patch
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