From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BA7A950C2B2 for ; Fri, 4 Sep 2026 18:35:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788546926; cv=none; b=PLiJgJEL79gN/zAYKSO5aFofVDgioaAMoCbvA8JkJsHxMM+M9RuEUny27qOcGouBeBgTLuDa2nSBmt6PkJkPDk7k/exS8RW5YtJhg1t0+6ftr+zbOa+q+U2j6yse4PpDfQaSuVILHbZHwr4VFPsTkuNAT1Hyt2CkViDnXFEPCwM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788546926; c=relaxed/simple; bh=FTrU9uzrsTkKuT1LtyzCHXRtwTiHxqguNP+SHH6ihaM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Wj1BPyALnqE8XdwUqjPcAbLkKsGZvZ20ae2am7yEHSkziduht3FeUBSqYp/HFfvcey1dkqAmTIsJ/PNtN6FdSZcFEHPnLhBYC/VF/VWOOZQeKAEn20+sBwwyUGiLbOSoFvPOcZLyuIKFbSfkxeBMK/VQNZygOpfhVPxTUfQU2O0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=B8lNqKZb; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="B8lNqKZb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D7D011F00ADF; Fri, 4 Sep 2026 18:35:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788546919; bh=sFkeiC1d3NLCVwN0ItX6nVexXWKQ/M3u5RpZr0JziQQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=B8lNqKZbPRnmYDs0wgDYBcODmDjaAY9YqfXcyDWih0x3q6gTQchHxYvYB54qqaKIl qfM6gATsmOc7cvINlaC67zvuN/+VE2UMEilcKkmzn55sBlSoPV6VFRLlLrQp76eQlM DhWj8yTJ82FlqR8srrIKdmePJfLE0w4QS5bQm+b6lr8kQpVMYhCubiZrHonggDBrFs SzZuRL7fp31B6cmuQh9GuIoriJz5sTAjLIYeku4eM73Jlpdd1IBYaEw1knbwhQQ+GU 0feQNKVL4GpDG5ul1SEY2iodGshkneKq3tFKzLUOVmG3O71oyt4+LYkQXYZmw2VIwT ZTYpKtm77sJQg== From: Sasha Levin To: stable@vger.kernel.org Cc: Sergey Senozhatsky , Minchan Kim , Andrew Morton , Sasha Levin Subject: [PATCH 6.12.y 2/3] zram: use zram_read_from_zspool() in writeback Date: Fri, 4 Sep 2026 14:35:15 -0400 Message-ID: <20260904183516.1323937-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260904183516.1323937-1-sashal@kernel.org> References: <2026090305-desolate-sports-060e@gregkh> <20260904183516.1323937-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Sergey Senozhatsky [ Upstream commit b8d3ff7bb5111c6a88d5672469de445d9b46cf22 ] We only can read pages from zspool in writeback, zram_read_page() is not really right in that context not only because it's a more generic function that handles ZRAM_WB pages, but also because it requires us to unlock slot between slot flag check and actual page read. Use zram_read_from_zspool() instead and do slot flags check and page read under the same slot lock. Link: https://lkml.kernel.org/r/20241218063513.297475-7-senozhatsky@chromium.org Signed-off-by: Sergey Senozhatsky Cc: Minchan Kim Signed-off-by: Andrew Morton Stable-dep-of: 894913e2d35c ("zram: fix out-of-bounds access in writeback_store()") Signed-off-by: Sasha Levin --- drivers/block/zram/zram_drv.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index afd1eb7a8fffb..28b4ce88cf145 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -55,8 +55,8 @@ static size_t huge_class_size; static const struct block_device_operations zram_devops; static void zram_free_page(struct zram *zram, size_t index); -static int zram_read_page(struct zram *zram, struct page *page, u32 index, - struct bio *parent); +static int zram_read_from_zspool(struct zram *zram, struct page *page, + u32 index); static int zram_slot_trylock(struct zram *zram, u32 index) { @@ -694,14 +694,12 @@ static ssize_t writeback_store(struct device *dev, zram_set_flag(zram, index, ZRAM_UNDER_WB); /* Need for hugepage writeback racing */ zram_set_flag(zram, index, ZRAM_IDLE); - zram_slot_unlock(zram, index); - if (zram_read_page(zram, page, index, NULL)) { - zram_slot_lock(zram, index); + if (zram_read_from_zspool(zram, page, index)) { zram_clear_flag(zram, index, ZRAM_UNDER_WB); zram_clear_flag(zram, index, ZRAM_IDLE); - zram_slot_unlock(zram, index); - continue; + goto next; } + zram_slot_unlock(zram, index); bio_init(&bio, zram->bdev, &bio_vec, 1, REQ_OP_WRITE | REQ_SYNC); -- 2.53.0