From patchwork Thu Apr 20 12:03:06 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Westphal X-Patchwork-Id: 13218627 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 A5663C77B73 for ; Thu, 20 Apr 2023 12:03:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233808AbjDTMDS (ORCPT ); Thu, 20 Apr 2023 08:03:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57050 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232922AbjDTMDR (ORCPT ); Thu, 20 Apr 2023 08:03:17 -0400 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [IPv6:2a0a:51c0:0:237:300::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8DC3049FA for ; Thu, 20 Apr 2023 05:03:09 -0700 (PDT) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1ppT0E-0002J0-3Y; Thu, 20 Apr 2023 14:03:06 +0200 Date: Thu, 20 Apr 2023 14:03:06 +0200 From: Florian Westphal To: bpf@vger.kernel.org Cc: Eduard Zingerman , Dave Marchevsky Subject: bpf-next hang+kasan uaf refcount acquire splat when running test_progs Message-ID: MIME-Version: 1.0 Content-Disposition: inline Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Hello, while working on bpf-netfilter test cases i found that test_progs never invokes bpf_test_run(). After applying following small patch it gets called as expected. ... but then output just hangs. With KASAN enabled I see following splat, followed by a refcount saturation warning: BUG: KASAN: slab-out-of-bounds in bpf_refcount_acquire_impl+0x63/0xd0 Write of size 4 at addr ffff8881072b34e8 by task new_name/12847 CPU: 1 PID: 12847 Comm: new_name Not tainted 6.3.0-rc6+ #129 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-20220807_005459-localhost 04/01/2014 Call Trace: dump_stack_lvl+0x32/0x40 print_address_description.constprop.0+0x2b/0x3d0 ? bpf_refcount_acquire_impl+0x63/0xd0 print_report+0xb0/0x260 ? bpf_refcount_acquire_impl+0x63/0xd0 ? kasan_addr_to_slab+0x9/0x70 ? bpf_refcount_acquire_impl+0x63/0xd0 kasan_report+0xad/0xd0 ? bpf_refcount_acquire_impl+0x63/0xd0 kasan_check_range+0x13b/0x190 bpf_refcount_acquire_impl+0x63/0xd0 bpf_prog_affcc6c9d58016ca___insert_in_tree_and_list+0x54/0x131 bpf_prog_795203cdef4805f4_insert_and_remove_tree_true_list_true+0x15/0x11b bpf_test_run+0x2a0/0x5f0 ? bpf_test_timer_continue+0x430/0x430 ? kmem_cache_alloc+0xe5/0x260 ? kasan_set_track+0x21/0x30 ? krealloc+0x9e/0xe0 bpf_prog_test_run_skb+0x890/0x1270 ? __kmem_cache_free+0x9f/0x170 ? bpf_prog_test_run_raw_tp+0x570/0x570 ? __fget_light+0x52/0x4d0 ? map_update_elem+0x680/0x680 __sys_bpf+0x75e/0xd10 ? bpf_link_by_id+0xa0/0xa0 ? rseq_get_rseq_cs+0x67/0x650 ? __blkcg_punt_bio_submit+0x1b0/0x1b0 __x64_sys_bpf+0x6f/0xb0 do_syscall_64+0x3a/0x80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f2f6a8b392d Code: 5d c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d d3 e4 0c 00 f7 d8 64 89 01 48 RSP: 002b:00007ffe46938328 EFLAGS: 00000206 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 0000000007150690 RCX: 00007f2f6a8b392d RDX: 0000000000000050 RSI: 00007ffe46938360 RDI: 000000000000000a RBP: 00007ffe46938340 R08: 0000000000000064 R09: 00007ffe46938360 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007ffe46938b78 R14: 0000000000e09db0 R15: 00007f2f6a9ff000 I can also reproduce this on bpf-next/780c69830ec6b27e0224586ce26bc89552fcf163. Is this a known bug? If you can't reproduce this I can make .config available. Thanks. diff --git a/tools/testing/selftests/bpf/test_loader.c b/tools/testing/selftests/bpf/test_loader.c index 47e9e076bc8f..e2a1bdc5a570 100644 --- a/tools/testing/selftests/bpf/test_loader.c +++ b/tools/testing/selftests/bpf/test_loader.c @@ -587,7 +587,7 @@ void run_subtest(struct test_loader *tester, /* For some reason test_verifier executes programs * with all capabilities restored. Do the same here. */ - if (!restore_capabilities(&caps)) + if (restore_capabilities(&caps)) goto tobj_cleanup; do_prog_test_run(bpf_program__fd(tprog), &retval);