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[209.85.220.65]) by mx.google.com with SMTPS id q130sor7093220ljb.16.2019.07.02.02.54.04 for (Google Transport Security); Tue, 02 Jul 2019 02:54:04 -0700 (PDT) Received-SPF: pass (google.com: domain of vitalywool@gmail.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=KDkySTJN; spf=pass (google.com: domain of vitalywool@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=vitalywool@gmail.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=hjyKVTfGLIvonwBnPeklb1p3eTYs2YkOVqXlW7TXq5I=; b=KDkySTJNPi9xp2C9AbgqC60PF/XlLQ5EkZL2DorhyaDXAZWlT23yYIPfStjb1pELpb mCt6Dw0DoiVH9E0SF4LlIrX0Qg/iIO4boobYYGgAwfSUTcsn0iXNwkW0tj6VYZOQyIxJ /4JMcJsCj17lggg5m+gtFf24FOocdJjTtV1WH/HxcaH675SYrW59q555fZDLlfk5v1xz X/OxWEagVMcjk6FONjuM7VNPBOhVAULnNjBwbn6W7429kkDrpbgwYOw0LUYxZwLDEYen UqnqI9mCajyZkBl0t7/k3WXjxkERDDuwlXPAGc6Dp44e4YV59PKX2b9rkuqatb8B1oYO dQ4A== X-Google-Smtp-Source: APXvYqzwuDK5paYci+EjBub1RottsQW8Z3v6j5P39yYdQ08dZkdClJyhBoe5GwYmEBPA5Rl/qWZ8LnknbwME5uslAZ4= X-Received: by 2002:a2e:8ed2:: with SMTP id e18mr16909326ljl.235.1562061244143; Tue, 02 Jul 2019 02:54:04 -0700 (PDT) MIME-Version: 1.0 References: <20190702005122.41036-1-henryburns@google.com> In-Reply-To: <20190702005122.41036-1-henryburns@google.com> From: Vitaly Wool Date: Tue, 2 Jul 2019 12:53:51 +0300 Message-ID: Subject: Re: [PATCH v2] mm/z3fold.c: Lock z3fold page before __SetPageMovable() To: Henry Burns Cc: Andrew Morton , Vitaly Vul , Mike Rapoport , Xidong Wang , Shakeel Butt , Jonathan Adams , Linux-MM , LKML Content-Type: text/plain; charset="UTF-8" X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Jul 2, 2019 at 3:51 AM Henry Burns wrote: > > __SetPageMovable() expects it's page to be locked, but z3fold.c doesn't > lock the page. Following zsmalloc.c's example we call trylock_page() and > unlock_page(). Also makes z3fold_page_migrate() assert that newpage is > passed in locked, as documentation. > > Signed-off-by: Henry Burns > Suggested-by: Vitaly Wool Acked-by: Vitaly Wool Thanks! > --- > Changelog since v1: > - Added an if statement around WARN_ON(trylock_page(page)) to avoid > unlocking a page locked by a someone else. > > mm/z3fold.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/mm/z3fold.c b/mm/z3fold.c > index e174d1549734..6341435b9610 100644 > --- a/mm/z3fold.c > +++ b/mm/z3fold.c > @@ -918,7 +918,10 @@ static int z3fold_alloc(struct z3fold_pool *pool, size_t size, gfp_t gfp, > set_bit(PAGE_HEADLESS, &page->private); > goto headless; > } > - __SetPageMovable(page, pool->inode->i_mapping); > + if (!WARN_ON(!trylock_page(page))) { > + __SetPageMovable(page, pool->inode->i_mapping); > + unlock_page(page); > + } > z3fold_page_lock(zhdr); > > found: > @@ -1325,6 +1328,7 @@ static int z3fold_page_migrate(struct address_space *mapping, struct page *newpa > > 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); > -- > 2.22.0.410.gd8fdbe21b5-goog >