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zsmalloc: fix races between modifications of fullness and isolated

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[ Upstream commit 4b5d1e47b6 ]

We encountered many kernel exceptions of VM_BUG_ON(zspage->isolated ==
0) in dec_zspage_isolation() and BUG_ON(!pages[1]) in zs_unmap_object()
lately.  This issue only occurs when migration and reclamation occur at
the same time.

With our memory stress test, we can reproduce this issue several times
a day.  We have no idea why no one else encountered this issue.  BTW,
we switched to the new kernel version with this defect a few months
ago.

Since fullness and isolated share the same unsigned int, modifications of
them should be protected by the same lock.

[andrew.yang@mediatek.com: move comment]
  Link: https://lkml.kernel.org/r/20230727062910.6337-1-andrew.yang@mediatek.com
Link: https://lkml.kernel.org/r/20230721063705.11455-1-andrew.yang@mediatek.com
Fixes: c4549b8711 ("zsmalloc: remove zspage isolation for migration")
Signed-off-by: Andrew Yang <andrew.yang@mediatek.com>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Andrew Yang
2023-07-21 14:37:01 +08:00
committed by Greg Kroah-Hartman
parent 802b34e992
commit f872672edd
1 changed files with 9 additions and 5 deletions
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14
mm/zsmalloc.c
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@@ -1816,6 +1816,7 @@ static void replace_sub_page(struct size_class *class, struct zspage *zspage,
static bool zs_page_isolate(struct page *page, isolate_mode_t mode) static bool zs_page_isolate(struct page *page, isolate_mode_t mode)
{ {
struct zs_pool *pool;
struct zspage *zspage; struct zspage *zspage;
/* /*
@@ -1826,9 +1827,10 @@ static bool zs_page_isolate(struct page *page, isolate_mode_t mode)
VM_BUG_ON_PAGE(PageIsolated(page), page); VM_BUG_ON_PAGE(PageIsolated(page), page);
zspage = get_zspage(page); zspage = get_zspage(page);
migrate_write_lock(zspage); pool = zspage->pool;
spin_lock(&pool->lock);
inc_zspage_isolation(zspage); inc_zspage_isolation(zspage);
migrate_write_unlock(zspage); spin_unlock(&pool->lock);
return true; return true;
} }
@@ -1895,12 +1897,12 @@ static int zs_page_migrate(struct page *newpage, struct page *page,
kunmap_atomic(s_addr); kunmap_atomic(s_addr);
replace_sub_page(class, zspage, newpage, page); replace_sub_page(class, zspage, newpage, page);
dec_zspage_isolation(zspage);
/* /*
* Since we complete the data copy and set up new zspage structure, * Since we complete the data copy and set up new zspage structure,
* it's okay to release the pool's lock. * it's okay to release the pool's lock.
*/ */
spin_unlock(&pool->lock); spin_unlock(&pool->lock);
dec_zspage_isolation(zspage);
migrate_write_unlock(zspage); migrate_write_unlock(zspage);
get_page(newpage); get_page(newpage);
@@ -1917,15 +1919,17 @@ static int zs_page_migrate(struct page *newpage, struct page *page,
static void zs_page_putback(struct page *page) static void zs_page_putback(struct page *page)
{ {
struct zs_pool *pool;
struct zspage *zspage; struct zspage *zspage;
VM_BUG_ON_PAGE(!PageMovable(page), page); VM_BUG_ON_PAGE(!PageMovable(page), page);
VM_BUG_ON_PAGE(!PageIsolated(page), page); VM_BUG_ON_PAGE(!PageIsolated(page), page);
zspage = get_zspage(page); zspage = get_zspage(page);
migrate_write_lock(zspage); pool = zspage->pool;
spin_lock(&pool->lock);
dec_zspage_isolation(zspage); dec_zspage_isolation(zspage);
migrate_write_unlock(zspage); spin_unlock(&pool->lock);
} }
static const struct movable_operations zsmalloc_mops = { static const struct movable_operations zsmalloc_mops = {