From patchwork Tue Aug 22 13:38:04 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hou Tao X-Patchwork-Id: 13360614 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (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 264937F for ; Tue, 22 Aug 2023 13:06:16 +0000 (UTC) Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 37C97CD8 for ; Tue, 22 Aug 2023 06:06:12 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.30.67.169]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4RVV3408dYz4f3m8d for ; Tue, 22 Aug 2023 21:06:08 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.124.27]) by APP4 (Coremail) with SMTP id gCh0CgBH16m+suRk0ldIBQ--.4082S4; Tue, 22 Aug 2023 21:06:08 +0800 (CST) From: Hou Tao To: bpf@vger.kernel.org Cc: Martin KaFai Lau , Alexei Starovoitov , Andrii Nakryiko , Song Liu , Hao Luo , Yonghong Song , Daniel Borkmann , KP Singh , Stanislav Fomichev , Jiri Olsa , John Fastabend , houtao1@huawei.com Subject: [PATCH bpf-next 0/3] bpf: Enable preemption after irq_work_raise() completes Date: Tue, 22 Aug 2023 21:38:04 +0800 Message-Id: <20230822133807.3198625-1-houtao@huaweicloud.com> X-Mailer: git-send-email 2.29.2 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-CM-TRANSID: gCh0CgBH16m+suRk0ldIBQ--.4082S4 X-Coremail-Antispam: 1UD129KBjvJXoW7tF4rAr4DWFWfKr1UuFykXwb_yoW8JFy7pF 4fKryFya1kAFy7Jrya93Z2yryrGa1rXr48Kr1fXFyUZ395JrykJr1xKr15Wr93JrWjqFWr Zr4vkF4kCw18Zw7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUk2b4IE77IF4wAFF20E14v26r4j6ryUM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28lY4IEw2IIxxk0rwA2F7IY1VAKz4 vEj48ve4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Xr0_Ar1l84ACjcxK6xIIjxv20xvEc7Cj xVAFwI0_Gr1j6F4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x 0267AKxVW0oVCq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG 6I80ewAv7VC0I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFV Cjc4AY6r1j6r4UM4x0Y48IcxkI7VAKI48JM4IIrI8v6xkF7I0E8cxan2IY04v7MxAIw28I cxkI7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2 IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVWUtVW8ZwCIc40Y0x0EwIxGrwCI 42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AKxVW8JVWxJwCI42 IY6xAIw20EY4v20xvaj40_WFyUJVCq3wCI42IY6I8E87Iv67AKxVWUJVW8JwCI42IY6I8E 87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjxUrR6zUUUUU X-CM-SenderInfo: xkrx3t3r6k3tpzhluzxrxghudrp/ X-CFilter-Loop: Reflected X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,SPF_HELO_NONE, SPF_NONE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: bpf@iogearbox.net From: Hou Tao Hi, The patchset aims to fix the problem that bpf_mem_alloc() may return NULL unexpectedly when multiple bpf_mem_alloc() are invoked concurrently under process context and there is still free memory available. The problem was found when doing stress test for qp-trie but the same problem also exists for bpf_obj_new() as demonstrated in patch #3. Patch #1 fixes the race between unit_alloc() and unit_alloc(). Patch #2 fixes the race between unit_alloc() and unit_free(). And patch #3 adds a selftest for the problem. Please see individual patches for more details. And comments are always welcome. Hou Tao (3): bpf: Enable preemption after irq_work_raise() in unit_alloc() bpf: Enable preemption after irq_work_raise() in unit_free{_rcu}() selftests/bpf: Test preemption between bpf_obj_new() and bpf_obj_drop() kernel/bpf/memalloc.c | 12 ++ .../bpf/prog_tests/preempted_bpf_ma_op.c | 89 +++++++++++++++ .../selftests/bpf/progs/preempted_bpf_ma_op.c | 106 ++++++++++++++++++ 3 files changed, 207 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/preempted_bpf_ma_op.c create mode 100644 tools/testing/selftests/bpf/progs/preempted_bpf_ma_op.c