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Message-ID: <20251126104254.1779732-1-metze@samba.org>
Date: Wed, 26 Nov 2025 11:42:54 +0100
From: Stefan Metzmacher <metze@...ba.org>
To: linux-rdma@...r.kernel.org
Cc: metze@...ba.org,
Bernard Metzler <bernard.metzler@...ux.dev>,
Jason Gunthorpe <jgg@...pe.ca>,
Leon Romanovsky <leon@...nel.org>,
netdev@...r.kernel.org,
linux-cifs@...r.kernel.org
Subject: [PATCH] RDMA/siw: reclassify sockets in order to avoid false positives from lockdep
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 <bernard.metzler@...ux.dev>
Cc: Jason Gunthorpe <jgg@...pe.ca>
Cc: Leon Romanovsky <leon@...nel.org>
Cc: linux-rdma@...r.kernel.org
Cc: netdev@...r.kernel.org
Cc: linux-cifs@...r.kernel.org
Signed-off-by: Stefan Metzmacher <metze@...ba.org>
---
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.
--
2.43.0
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