From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-174.mta1.migadu.com (out-174.mta1.migadu.com [95.215.58.174]) (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 611FC18DB35 for ; Sat, 20 Jun 2026 13:25:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.174 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781961919; cv=none; b=OXfqF2AeSvZWCd4YiWyr4By6TQex40COM+T/AIYMlpF6dPUzW+NtBe6ziecaMrCVjk/93CQt4TDjqQwrENN85Fc05aimquu2PHMQpqsjLavX1r/OWUbQ5f/iazyHjFUgDlEZIqRKsvaUcjwqiLb7yjrh/Xd0HyGtDaOffZgIGOA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781961919; c=relaxed/simple; bh=Asuxszf/bAwC9ualoko64JrOS2xrhOR5jGL/gDpMV/c=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=OcNYS0fGp5KyJSUHGH244BLh8mO7Z2aDa38VjtxfB8QX5TMKyULypMRzus0wVMqvAs7zAFtBL3lC3wFsCtSgOI7NoIvs+Z/KfhpeCyzFtkVblbbRtw56EHS78AbGJ70Bn89E/7Gokg8qj0fknIkdz14rz/Nudm50vDbjKxQsXNM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=jHcV0dZI; arc=none smtp.client-ip=95.215.58.174 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="jHcV0dZI" Message-ID: <6f34efb8-c7e7-490c-bef1-c4c7da9a706e@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1781961915; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=afi4i6B2BdOEvMjupBy9U4sefc34AGzac9BLN7m560Q=; b=jHcV0dZIrmogmx86GXkj6i17E67BCMvSa6cyRpNc4KlXMAYX27kdbi6PHog1WPauMz7Rdu UtwvBrU2Dpc2yPJZcmAnxTJJlSu2cQN4jAh3qgdD/J6lTov9gVmYNVgtIBvQGSBpS5Pon1 f+/56RKU3j9aFs3d2/DvXynaIjF54gc= Date: Sat, 20 Jun 2026 21:24:50 +0800 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH bpf v2] bpf, sockmap: disallow update and delete from tc, xdp and flow_dissector To: Sechang Lim , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , John Fastabend , Eduard Zingerman , Kumar Kartikeya Dwivedi , "David S . Miller" , Jakub Kicinski , Jesper Dangaard Brouer Cc: Martin KaFai Lau , Song Liu , Yonghong Song , Jiri Olsa , Stanislav Fomichev , Lorenz Bauer , bpf@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org References: <20260620034632.2308-1-rhkrqnwk98@gmail.com> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Jiayuan Chen In-Reply-To: <20260620034632.2308-1-rhkrqnwk98@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT On 6/20/26 11:46 AM, Sechang Lim wrote: > sock_map_update_common() and __sock_map_delete() hold stab->lock and call > sock_map_unref() -> sock_map_del_link(), which takes sk_callback_lock for > write. That gives the order stab->lock -> sk_callback_lock. > > The reverse order comes from the SK_SKB stream parser. > sk_psock_strp_data_ready() holds sk_callback_lock for read, and after the > verdict tcp_bpf_strp_read_sock() acks the consumed data inline via > __tcp_cleanup_rbuf(). The ACK goes out egress, where a sched_cls program > deletes from the sockmap and takes stab->lock: > > WARNING: possible circular locking dependency detected > 7.1.0-rc6 Not tainted > ------------------------------------------------------ > syz.9.8824 is trying to acquire lock: > (&stab->lock){+.-.}-{3:3}, at: __sock_map_delete net/core/sock_map.c:421 > but task is already holding lock: > (clock-AF_INET){++.-}-{3:3}, at: sk_psock_strp_data_ready net/core/skmsg.c:1173 > > -> #1 (clock-AF_INET){++.-}-{3:3}: > _raw_write_lock_bh > sock_map_del_link net/core/sock_map.c:167 > sock_map_unref net/core/sock_map.c:184 > sock_map_update_common net/core/sock_map.c:509 > sock_map_update_elem_sys net/core/sock_map.c:588 > map_update_elem kernel/bpf/syscall.c:1805 > > -> #0 (&stab->lock){+.-.}-{3:3}: > _raw_spin_lock_bh > __sock_map_delete net/core/sock_map.c:421 > sock_map_delete_elem net/core/sock_map.c:452 > bpf_prog_06044d24140080b6 > tcx_run net/core/dev.c:4451 > sch_handle_egress net/core/dev.c:4541 > __dev_queue_xmit net/core/dev.c:4808 > ... > tcp_bpf_strp_read_sock net/ipv4/tcp_bpf.c:701 > strp_data_ready net/strparser/strparser.c:402 > sk_psock_strp_data_ready net/core/skmsg.c:1174 > tcp_data_queue net/ipv4/tcp_input.c:5661 > > Possible unsafe locking scenario: > > CPU0 CPU1 > ---- ---- > rlock(clock-AF_INET); > lock(&stab->lock); > lock(clock-AF_INET); > lock(&stab->lock); > > *** DEADLOCK *** > > A tc, xdp or flow_dissector program has no reason to update or delete a > sockmap, and redirect does not go through here. Drop them from > may_update_sockmap() so the verifier rejects it. It also closes the > matching sockhash inversion. > > Fixes: 0126240f448d ("bpf: sockmap: Allow update from BPF") > Suggested-by: John Fastabend > Signed-off-by: Sechang Lim > --- > v2: > - reject sockmap update/delete from tc, xdp and flow_dissector (John > Fastabend) > - fix the changelog (Jiayuan Chen) > > v1: > - https://lore.kernel.org/all/20260616091153.2966617-1-rhkrqnwk98@gmail.com/ > > kernel/bpf/verifier.c | 4 ---- > 1 file changed, 4 deletions(-) > > diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c > index 7fb88e1cd7c4..94d225521b5a 100644 > --- a/kernel/bpf/verifier.c > +++ b/kernel/bpf/verifier.c > @@ -8766,11 +8766,7 @@ static bool may_update_sockmap(struct bpf_verifier_env *env, int func_id) > return true; > break; > case BPF_PROG_TYPE_SOCKET_FILTER: > - case BPF_PROG_TYPE_SCHED_CLS: > - case BPF_PROG_TYPE_SCHED_ACT: > - case BPF_PROG_TYPE_XDP: > case BPF_PROG_TYPE_SK_REUSEPORT: > - case BPF_PROG_TYPE_FLOW_DISSECTOR: > case BPF_PROG_TYPE_SK_LOOKUP: > return true; > default: CI failed. https://github.com/kernel-patches/bpf/actions/runs/27859622337/job/82454035306 Please drop or change such trigger. Also, please drop Fixes tag and target to bpf-next for the same reason in you another thread. Nit: You can also manually fork and create pull request against https://github.com/kernel-patches/bpf/ to run full test to run the full test and make sure all tests pass before you send patch.