From patchwork Wed Aug 10 08:05:31 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hou Tao X-Patchwork-Id: 12940297 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 27FF8C282E7 for ; Wed, 10 Aug 2022 07:48:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231376AbiHJHsD (ORCPT ); Wed, 10 Aug 2022 03:48:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40996 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231368AbiHJHrf (ORCPT ); Wed, 10 Aug 2022 03:47:35 -0400 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 293226E8A2 for ; Wed, 10 Aug 2022 00:47:33 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.30.67.143]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4M2hnq4N6xzKPxD for ; Wed, 10 Aug 2022 15:46:07 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.124.27]) by APP2 (Coremail) with SMTP id Syh0CgDHsb2NYvNiIKmmAA--.61804S6; Wed, 10 Aug 2022 15:47:30 +0800 (CST) From: Hou Tao To: bpf@vger.kernel.org, Yonghong Song Cc: Andrii Nakryiko , Alexei Starovoitov , Daniel Borkmann , Martin KaFai Lau , Song Liu , KP Singh , "David S . Miller" , Jakub Kicinski , Stanislav Fomichev , Hao Luo , Jiri Olsa , John Fastabend , Lorenz Bauer , houtao1@huawei.com Subject: [PATCH bpf v2 2/9] bpf: Acquire map uref in .init_seq_private for hash map iterator Date: Wed, 10 Aug 2022 16:05:31 +0800 Message-Id: <20220810080538.1845898-3-houtao@huaweicloud.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20220810080538.1845898-1-houtao@huaweicloud.com> References: <20220810080538.1845898-1-houtao@huaweicloud.com> MIME-Version: 1.0 X-CM-TRANSID: Syh0CgDHsb2NYvNiIKmmAA--.61804S6 X-Coremail-Antispam: 1UD129KBjvJXoW7ZryDAF1DGw4rZF4DZw4UCFg_yoW8Gr4UpF Z5KrWUCw48XF4kuan5JanruFWrAr15u34ftF4kt34F9rWUWr1DWr1rGFySvFy5urW0yr4S v3429a18Ca4UXrDanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUB0b4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6r1S6rWUM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUXw A2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxS w2x7M28EF7xvwVC0I7IYx2IY67AKxVWDJVCq3wA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxV W8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E14v2 6rxl6s0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMc Ij6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_ Jr0_Gr1lF7xvr2IYc2Ij64vIr41lFIxGxcIEc7CjxVA2Y2ka0xkIwI1l42xK82IYc2Ij64 vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8G jcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r4a6rW5MIIYrxkI7VAKI48JMIIF0xvE2I x0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r4j6F4UMIIF0xvE42xK 8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWUJVW8JwCI42IY6I8E87Iv6xkF7I 0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjxUFa9-UUUUU X-CM-SenderInfo: xkrx3t3r6k3tpzhluzxrxghudrp/ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net From: Hou Tao bpf_iter_attach_map() acquires a map uref, and the uref may be released before or in the middle of iterating map elements. For example, the uref could be released in bpf_iter_detach_map() as part of bpf_link_release(), or could be released in bpf_map_put_with_uref() as part of bpf_map_release(). So acquiring an extra map uref in bpf_iter_init_hash_map() and releasing it in bpf_iter_fini_hash_map(). Fixes: d6c4503cc296 ("bpf: Implement bpf iterator for hash maps") Signed-off-by: Hou Tao Acked-by: Yonghong Song --- kernel/bpf/hashtab.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c index da7578426a46..da8c0177f773 100644 --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -2064,6 +2064,7 @@ static int bpf_iter_init_hash_map(void *priv_data, seq_info->percpu_value_buf = value_buf; } + bpf_map_inc_with_uref(map); seq_info->map = map; seq_info->htab = container_of(map, struct bpf_htab, map); return 0; @@ -2073,6 +2074,7 @@ static void bpf_iter_fini_hash_map(void *priv_data) { struct bpf_iter_seq_hash_map_info *seq_info = priv_data; + bpf_map_put_with_uref(seq_info->map); kfree(seq_info->percpu_value_buf); }