shinys000114/linux
1
0
Fork 0
mirror of https://github.com/hardkernel/linux.git synced 2026-06-05 02:21:52 +09:00
Code Issues Packages Projects Releases Wiki Activity

BACKPORT: zsmalloc: fix races between modifications of fullness and isolated

Browse Source 
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")
Change-Id: I4aeda0715d65f828bb88ad6fbf36b9927c7a5c4b
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>
(cherry picked from commit 4b5d1e47b6)
Bug: 297093100
[ Kalesh Singh - Fix trivial conflicts in zs_page_putback()]
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
This commit is contained in:
Andrew Yang
2023-07-21 14:37:01 +08:00
committed by Kalesh Singh
parent c0e84be923
commit cb440cecb2
1 changed files with 9 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

14
mm/zsmalloc.c
View File

@@ -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)
{
struct zs_pool *pool;
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);
zspage = get_zspage(page);
migrate_write_lock(zspage);
pool = zspage->pool;
spin_lock(&pool->lock);
inc_zspage_isolation(zspage);
migrate_write_unlock(zspage);
spin_unlock(&pool->lock);
return true;
}
@@ -1895,12 +1897,12 @@ static int zs_page_migrate(struct page *newpage, struct page *page,
kunmap_atomic(s_addr);
replace_sub_page(class, zspage, newpage, page);
dec_zspage_isolation(zspage);
/*
* Since we complete the data copy and set up new zspage structure,
* it's okay to release the pool's lock.
*/
spin_unlock(&pool->lock);
dec_zspage_isolation(zspage);
migrate_write_unlock(zspage);
get_page(newpage);
@@ -1918,14 +1920,16 @@ static int zs_page_migrate(struct page *newpage, struct page *page,
static void zs_page_putback(struct page *page)
{
struct zspage *zspage;
struct zs_pool *pool;
VM_BUG_ON_PAGE(!PageMovable(page), page);
VM_BUG_ON_PAGE(!PageIsolated(page), page);
zspage = get_zspage(page);
migrate_write_lock(zspage);
pool = zspage->pool;
spin_lock(&pool->lock);
dec_zspage_isolation(zspage);
migrate_write_unlock(zspage);
spin_unlock(&pool->lock);
}
static const struct movable_operations zsmalloc_mops = {