From: Henry Burns <henryburns@xxxxxxxxxx> Subject: mm/z3fold.c: lock z3fold page before __SetPageMovable() Following zsmalloc.c's example we call trylock_page() and unlock_page(). Also make z3fold_page_migrate() assert that newpage is passed in locked, as per the documentation. [akpm@xxxxxxxxxxxxxxxxxxxx: fix trylock_page return value test, per Shakeel] Link: http://lkml.kernel.org/r/20190702005122.41036-1-henryburns@xxxxxxxxxx Link: http://lkml.kernel.org/r/20190702233538.52793-1-henryburns@xxxxxxxxxx Signed-off-by: Henry Burns <henryburns@xxxxxxxxxx> Suggested-by: Vitaly Wool <vitalywool@xxxxxxxxx> Acked-by: Vitaly Wool <vitalywool@xxxxxxxxx> Acked-by: David Rientjes <rientjes@xxxxxxxxxx> Reviewed-by: Shakeel Butt <shakeelb@xxxxxxxxxx> Cc: Vitaly Vul <vitaly.vul@xxxxxxxx> Cc: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx> Cc: Xidong Wang <wangxidong_97@xxxxxxx> Cc: Jonathan Adams <jwadams@xxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/z3fold.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) --- a/mm/z3fold.c~mm-z3foldc-lock-z3fold-page-before-__setpagemovable +++ a/mm/z3fold.c @@ -924,7 +924,16 @@ retry: set_bit(PAGE_HEADLESS, &page->private); goto headless; } - __SetPageMovable(page, pool->inode->i_mapping); + if (can_sleep) { + lock_page(page); + __SetPageMovable(page, pool->inode->i_mapping); + unlock_page(page); + } else { + if (trylock_page(page)) { + __SetPageMovable(page, pool->inode->i_mapping); + unlock_page(page); + } + } z3fold_page_lock(zhdr); found: @@ -1331,6 +1340,7 @@ static int z3fold_page_migrate(struct ad VM_BUG_ON_PAGE(!PageMovable(page), page); VM_BUG_ON_PAGE(!PageIsolated(page), page); + VM_BUG_ON_PAGE(!PageLocked(newpage), newpage); zhdr = page_address(page); pool = zhdr_to_pool(zhdr); _
