From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-184.mta0.migadu.com (out-184.mta0.migadu.com [91.218.175.184]) (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 895D1303C9E for ; Wed, 26 Nov 2025 14:48:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.184 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764168512; cv=none; b=M6JEDgFiBH4uKVRWKhTZU0UaUQEpo9xYQT2jY5Ocq7+vrgG25r3JSABCRSxrRyMLG0/0w6Vfbgt5es/MxkreznXxGFL+3n/05CH4rXCstlEEHq8gUvUCUVuHIS6qmDctTYp7LJxY/rDgMCKfTtRBRSnA/ipPr8nFbwsdG6dwjIQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764168512; c=relaxed/simple; bh=sPZMoPcrpJ7sfHw5qRw4SulhCS30oyCh8yl+mxi4tb0=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=QBu6egpUMb/ctFBlpBMY+DTnnt7Io6tQfsSkUAIQWu2JvHbVKe+D4cLDQJ/4Bdyn8yCxreyHosE477dUMuaPb2V+aVUrKc0g0dlx1ORjwd1nQmIZ77JqzS3gbPfw7B739CYgvuOHF6ojG+RJ8mShVjLmjIDFqJN4l6aI7VwLn3E= 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=QUK13tyN; arc=none smtp.client-ip=91.218.175.184 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="QUK13tyN" Message-ID: <7fe312bd-24f8-4359-8423-f2d98a0bfce5@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1764168508; 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=hpY9CCPv7Nu2Ao5uOU/REkofxjO7Neu7S1aiJh3aFZQ=; b=QUK13tyNThVtnXYlA0zZJ5Mze/mK1s+LBpbEPEvIt5tSciDxp8NUo+crxS2kZ0Xw+q74EQ p0PKuelcGDbLTtGg/O72/MGc1ErQ7FW7oLMKndSL9YYgr2hSX/3pG3UF8sDisiR59Bc0AY FfazZDC7W3LJdvUAjSB8MljqVZKDNFg= Date: Wed, 26 Nov 2025 15:48:26 +0100 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH] RDMA/siw: reclassify sockets in order to avoid false positives from lockdep To: Stefan Metzmacher , linux-rdma@vger.kernel.org Cc: Jason Gunthorpe , Leon Romanovsky , netdev@vger.kernel.org, linux-cifs@vger.kernel.org References: <20251126104254.1779732-1-metze@samba.org> <25ae6db1-856f-4592-a4fa-8a927426ed72@linux.dev> <73b14f8b-03dc-4ed0-ad07-b33460dc70e7@samba.org> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Bernard Metzler In-Reply-To: <73b14f8b-03dc-4ed0-ad07-b33460dc70e7@samba.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT On 26.11.2025 15:28, Stefan Metzmacher wrote: > Hi Bernard, > >> On 26.11.2025 11:42, Stefan Metzmacher wrote: >>> While developing IPPROTO_SMBDIRECT support for the code >>> under fs/smb/common/smbdirect [1], I noticed false positives like this: >>> >>> [T79] ====================================================== >>> [T79] WARNING: possible circular locking dependency detected >>> [T79] 6.18.0-rc4-metze-kasan-lockdep.01+ #1 Tainted: G           OE >>> [T79] ------------------------------------------------------ >>> [T79] kworker/2:0/79 is trying to acquire lock: >>> [T79] ffff88801f968278 (sk_lock-AF_INET){+.+.}-{0:0}, >>>                          at: sock_set_reuseaddr+0x14/0x70 >>> [T79] >>>          but task is already holding lock: >>> [T79] ffffffffc10f7230 (lock#9){+.+.}-{4:4}, >>>                          at: rdma_listen+0x3d2/0x740 [rdma_cm] >>> [T79] >>>          which lock already depends on the new lock. >>> >>> [T79] >>>          the existing dependency chain (in reverse order) is: >>> [T79] >>>          -> #1 (lock#9){+.+.}-{4:4}: >>> [T79]        __lock_acquire+0x535/0xc30 >>> [T79]        lock_acquire.part.0+0xb3/0x240 >>> [T79]        lock_acquire+0x60/0x140 >>> [T79]        __mutex_lock+0x1af/0x1c10 >>> [T79]        mutex_lock_nested+0x1b/0x30 >>> [T79]        cma_get_port+0xba/0x7d0 [rdma_cm] >>> [T79]        rdma_bind_addr_dst+0x598/0x9a0 [rdma_cm] >>> [T79]        cma_bind_addr+0x107/0x320 [rdma_cm] >>> [T79]        rdma_resolve_addr+0xa3/0x830 [rdma_cm] >>> [T79]        destroy_lease_table+0x12b/0x420 [ksmbd] >>> [T79]        ksmbd_NTtimeToUnix+0x3e/0x80 [ksmbd] >>> [T79]        ndr_encode_posix_acl+0x6e9/0xab0 [ksmbd] >>> [T79]        ndr_encode_v4_ntacl+0x53/0x870 [ksmbd] >>> [T79]        __sys_connect_file+0x131/0x1c0 >>> [T79]        __sys_connect+0x111/0x140 >>> [T79]        __x64_sys_connect+0x72/0xc0 >>> [T79]        x64_sys_call+0xe7d/0x26a0 >>> [T79]        do_syscall_64+0x93/0xff0 >>> [T79]        entry_SYSCALL_64_after_hwframe+0x76/0x7e >>> [T79] >>>          -> #0 (sk_lock-AF_INET){+.+.}-{0:0}: >>> [T79]        check_prev_add+0xf3/0xcd0 >>> [T79]        validate_chain+0x466/0x590 >>> [T79]        __lock_acquire+0x535/0xc30 >>> [T79]        lock_acquire.part.0+0xb3/0x240 >>> [T79]        lock_acquire+0x60/0x140 >>> [T79]        lock_sock_nested+0x3b/0xf0 >>> [T79]        sock_set_reuseaddr+0x14/0x70 >>> [T79]        siw_create_listen+0x145/0x1540 [siw] >>> [T79]        iw_cm_listen+0x313/0x5b0 [iw_cm] >>> [T79]        cma_iw_listen+0x271/0x3c0 [rdma_cm] >>> [T79]        rdma_listen+0x3b1/0x740 [rdma_cm] >>> [T79]        cma_listen_on_dev+0x46a/0x750 [rdma_cm] >>> [T79]        rdma_listen+0x4b0/0x740 [rdma_cm] >>> [T79]        ksmbd_rdma_init+0x12b/0x270 [ksmbd] >>> [T79]        ksmbd_conn_transport_init+0x26/0x70 [ksmbd] >>> [T79]        server_ctrl_handle_work+0x1e5/0x280 [ksmbd] >>> [T79]        process_one_work+0x86c/0x1930 >>> [T79]        worker_thread+0x6f0/0x11f0 >>> [T79]        kthread+0x3ec/0x8b0 >>> [T79]        ret_from_fork+0x314/0x400 >>> [T79]        ret_from_fork_asm+0x1a/0x30 >>> [T79] >>>          other info that might help us debug this: >>> >>> [T79]  Possible unsafe locking scenario: >>> >>> [T79]        CPU0                    CPU1 >>> [T79]        ----                    ---- >>> [T79]   lock(lock#9); >>> [T79]                                lock(sk_lock-AF_INET); >>> [T79]                                lock(lock#9); >>> [T79]   lock(sk_lock-AF_INET); >>> [T79] >>>           *** DEADLOCK *** >>> >>> [T79] 5 locks held by kworker/2:0/79: >>> [T79] #0: ffff88800120b158 ((wq_completion)events_long){+.+.}-{0:0}, >>>                             at: process_one_work+0xfca/0x1930 >>> [T79] #1: ffffc9000474fd00 ((work_completion)(&ctrl->ctrl_work)) >>>                             {+.+.}-{0:0}, >>>                             at: process_one_work+0x804/0x1930 >>> [T79] #2: ffffffffc11307d0 (ctrl_lock){+.+.}-{4:4}, >>>                             at: server_ctrl_handle_work+0x21/0x280 [ksmbd] >>> [T79] #3: ffffffffc11347b0 (init_lock){+.+.}-{4:4}, >>>                             at: ksmbd_conn_transport_init+0x18/0x70 [ksmbd] >>> [T79] #4: ffffffffc10f7230 (lock#9){+.+.}-{4:4}, >>>                              at: rdma_listen+0x3d2/0x740 [rdma_cm] >>> [T79] >>>          stack backtrace: >>> [T79] CPU: 2 UID: 0 PID: 79 Comm: kworker/2:0 Kdump: loaded >>>        Tainted: G           OE >>>        6.18.0-rc4-metze-kasan-lockdep.01+ #1 PREEMPT(voluntary) >>> [T79] Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE >>> [T79] Hardware name: innotek GmbH VirtualBox/VirtualBox, >>>        BIOS VirtualBox 12/01/2006 >>> [T79] Workqueue: events_long server_ctrl_handle_work [ksmbd] >>> ... >>> [T79]  print_circular_bug+0xfd/0x130 >>> [T79]  check_noncircular+0x150/0x170 >>> [T79]  check_prev_add+0xf3/0xcd0 >>> [T79]  validate_chain+0x466/0x590 >>> [T79]  __lock_acquire+0x535/0xc30 >>> [T79]  ? srso_alias_return_thunk+0x5/0xfbef5 >>> [T79]  lock_acquire.part.0+0xb3/0x240 >>> [T79]  ? sock_set_reuseaddr+0x14/0x70 >>> [T79]  ? srso_alias_return_thunk+0x5/0xfbef5 >>> [T79]  ? __kasan_check_write+0x14/0x30 >>> [T79]  ? srso_alias_return_thunk+0x5/0xfbef5 >>> [T79]  ? apparmor_socket_post_create+0x180/0x700 >>> [T79]  lock_acquire+0x60/0x140 >>> [T79]  ? sock_set_reuseaddr+0x14/0x70 >>> [T79]  lock_sock_nested+0x3b/0xf0 >>> [T79]  ? sock_set_reuseaddr+0x14/0x70 >>> [T79]  sock_set_reuseaddr+0x14/0x70 >>> [T79]  siw_create_listen+0x145/0x1540 [siw] >>> [T79]  ? srso_alias_return_thunk+0x5/0xfbef5 >>> [T79]  ? local_clock_noinstr+0xe/0xd0 >>> [T79]  ? __pfx_siw_create_listen+0x10/0x10 [siw] >>> [T79]  ? trace_preempt_on+0x4c/0x130 >>> [T79]  ? __raw_spin_unlock_irqrestore+0x4a/0x90 >>> [T79]  ? srso_alias_return_thunk+0x5/0xfbef5 >>> [T79]  ? preempt_count_sub+0x52/0x80 >>> [T79]  iw_cm_listen+0x313/0x5b0 [iw_cm] >>> [T79]  cma_iw_listen+0x271/0x3c0 [rdma_cm] >>> [T79]  ? srso_alias_return_thunk+0x5/0xfbef5 >>> [T79]  rdma_listen+0x3b1/0x740 [rdma_cm] >>> [T79]  ? _raw_spin_unlock+0x2c/0x60 >>> [T79]  ? __pfx_rdma_listen+0x10/0x10 [rdma_cm] >>> [T79]  ? rdma_restrack_add+0x12c/0x630 [ib_core] >>> [T79]  ? srso_alias_return_thunk+0x5/0xfbef5 >>> [T79]  cma_listen_on_dev+0x46a/0x750 [rdma_cm] >>> [T79]  rdma_listen+0x4b0/0x740 [rdma_cm] >>> [T79]  ? __pfx_rdma_listen+0x10/0x10 [rdma_cm] >>> [T79]  ? cma_get_port+0x30d/0x7d0 [rdma_cm] >>> [T79]  ? srso_alias_return_thunk+0x5/0xfbef5 >>> [T79]  ? rdma_bind_addr_dst+0x598/0x9a0 [rdma_cm] >>> [T79]  ksmbd_rdma_init+0x12b/0x270 [ksmbd] >>> [T79]  ? __pfx_ksmbd_rdma_init+0x10/0x10 [ksmbd] >>> [T79]  ? srso_alias_return_thunk+0x5/0xfbef5 >>> [T79]  ? srso_alias_return_thunk+0x5/0xfbef5 >>> [T79]  ? register_netdevice_notifier+0x1dc/0x240 >>> [T79]  ksmbd_conn_transport_init+0x26/0x70 [ksmbd] >>> [T79]  server_ctrl_handle_work+0x1e5/0x280 [ksmbd] >>> [T79]  process_one_work+0x86c/0x1930 >>> [T79]  ? __pfx_process_one_work+0x10/0x10 >>> [T79]  ? srso_alias_return_thunk+0x5/0xfbef5 >>> [T79]  ? assign_work+0x16f/0x280 >>> [T79]  worker_thread+0x6f0/0x11f0 >>> >>> I was not able to reproduce this as I was testing with various >>> runs switching siw and rxe as well as IPPROTO_SMBDIRECT sockets, >>> while the above stack used siw with the non IPPROTO_SMBDIRECT >>> patches [1]. >>> >>> Even if this patch doesn't solve the above I think it's >>> a good idea to reclassify the sockets used by siw, >>> I also send patches for rxe to reclassify, as well >>> as my IPPROTO_SMBDIRECT socket patches [1] will do it, >>> this should minimize potential false positives. >>> >>> [1] >>> https://git.samba.org/?p=metze/linux/wip.git;a=shortlog;h=refs/heads/master-ipproto-smbdirect >>> >>> Cc: Bernard Metzler >>> Cc: Jason Gunthorpe >>> Cc: Leon Romanovsky >>> Cc: linux-rdma@vger.kernel.org >>> Cc: netdev@vger.kernel.org >>> Cc: linux-cifs@vger.kernel.org >>> Signed-off-by: Stefan Metzmacher >>> --- >>>   drivers/infiniband/sw/siw/siw_cm.c | 18 ++++++++++++++++++ >>>   1 file changed, 18 insertions(+) >>> >>> diff --git a/drivers/infiniband/sw/siw/siw_cm.c b/drivers/infiniband/sw/siw/siw_cm.c >>> index 708b13993fdf..b83abf0ea15e 100644 >>> --- a/drivers/infiniband/sw/siw/siw_cm.c >>> +++ b/drivers/infiniband/sw/siw/siw_cm.c >>> @@ -39,6 +39,22 @@ static void siw_cm_llp_error_report(struct sock *s); >>>   static int siw_cm_upcall(struct siw_cep *cep, enum iw_cm_event_type reason, >>>                int status); >>> + >>> +static struct lock_class_key siw_sk_key; >>> +static struct lock_class_key siw_slock_key; >>> + >>> +static inline void siw_reclassify_socket(struct socket *sock) >>> +{ >>> +    struct sock *sk = sock->sk; >>> + >>> +    if (WARN_ON_ONCE(!sock_allow_reclassification(sk))) >>> +        return; >>> + >>> +    sock_lock_init_class_and_name(sk, >>> +                      "slock-RDMA-SIW", &siw_slock_key, >>> +                      "sk_lock-RDMA-SIW", &siw_sk_key); >>> +} >>> + >>>   static void siw_sk_assign_cm_upcalls(struct sock *sk) >>>   { >>>       struct siw_cep *cep = sk_to_cep(sk); >>> @@ -1394,6 +1410,7 @@ int siw_connect(struct iw_cm_id *id, struct iw_cm_conn_param *params) >>>       rv = sock_create(v4 ? AF_INET : AF_INET6, SOCK_STREAM, IPPROTO_TCP, &s); >>>       if (rv < 0) >>>           goto error; >>> +    siw_reclassify_socket(s); >>>       /* >>>        * NOTE: For simplification, connect() is called in blocking >>> @@ -1770,6 +1787,7 @@ int siw_create_listen(struct iw_cm_id *id, int backlog) >>>       rv = sock_create(addr_family, SOCK_STREAM, IPPROTO_TCP, &s); >>>       if (rv < 0) >>>           return rv; >>> +    siw_reclassify_socket(s); >>>       /* >>>        * Allow binding local port when still in TIME_WAIT from last close. >> >> Thanks very much, makes all sense to me. I stumbled across it a while >> ago as well and quietly ignored it. Your solution is better. >> If I look through the other use cases of sock_lock_init_class_and_name(), >> I found it gated by >> #ifdef CONFIG_DEBUG_LOCK_ALLOC >> (see for example drivers/nvme/host/tcp.c). I think wee need that >> since only then the related sock_lock_xxx objects and functions are >> defined. >> drivers/nvme/host/tcp.c also has a nice comment on why this is >> needed. I think we shall have such comment as well - just to remind us >> later what we did. > > I think it will also compile and work fine without > CONFIG_DEBUG_LOCK_ALLOC, but I'll add it. And a comment. > > I hope you agree that we don't need the AF_INET vs. AF_INET6 > thing. Ooh, good your are pointing at this. I expect we need it the same way as nvme_tcp_reclassify_socket() does it - 2 keys for the two possible socket types since they may exist in parallel for the siw driver... So please add. Thank you! Bernard. > > Thanks! > metze