* [PATCH v2] RDMA/siw: reclassify sockets in order to avoid false positives from lockdep
@ 2025-11-26 15:08 Stefan Metzmacher
2025-11-26 15:46 ` Bernard Metzler
2025-11-27 12:10 ` Leon Romanovsky
0 siblings, 2 replies; 3+ messages in thread
From: Stefan Metzmacher @ 2025-11-26 15:08 UTC (permalink / raw)
To: linux-rdma
Cc: metze, Bernard Metzler, Jason Gunthorpe, Leon Romanovsky, netdev,
linux-cifs
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@linux.dev>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: linux-rdma@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: linux-cifs@vger.kernel.org
Signed-off-by: Stefan Metzmacher <metze@samba.org>
---
v2: - use CONFIG_DEBUG_LOCK_ALLOC (Bernard)
- add a comment (Bernard)
- AF_INET vs. AF_INET6 (Bernard)
---
drivers/infiniband/sw/siw/siw_cm.c | 51 ++++++++++++++++++++++++++++++
1 file changed, 51 insertions(+)
diff --git a/drivers/infiniband/sw/siw/siw_cm.c b/drivers/infiniband/sw/siw/siw_cm.c
index 708b13993fdf..79dd44cd6bc3 100644
--- a/drivers/infiniband/sw/siw/siw_cm.c
+++ b/drivers/infiniband/sw/siw/siw_cm.c
@@ -39,6 +39,55 @@ 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);
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+/*
+ * lockdep can detect false positive circular dependencies
+ * when there are user-space socket API users or in kernel
+ * users switching between a tcp and rdma transport.
+ * Maybe also switching between siw and rxe may cause
+ * problems as per default sockets are only classified
+ * by family and not by ip protocol. And there might
+ * be different locks used between the application
+ * and the low level sockets.
+ *
+ * Problems were seen with ksmbd.ko and cifs.ko,
+ * switching transports, use git blame to find
+ * more details.
+ */
+static struct lock_class_key siw_sk_key[2];
+static struct lock_class_key siw_slock_key[2];
+#endif /* CONFIG_DEBUG_LOCK_ALLOC */
+
+static inline void siw_reclassify_socket(struct socket *sock)
+{
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ struct sock *sk = sock->sk;
+
+ if (WARN_ON_ONCE(!sock_allow_reclassification(sk)))
+ return;
+
+ switch (sk->sk_family) {
+ case AF_INET:
+ sock_lock_init_class_and_name(sk,
+ "slock-AF_INET-RDMA-SIW",
+ &siw_slock_key[0],
+ "sk_lock-AF_INET-RDMA-SIW",
+ &siw_sk_key[0]);
+ break;
+ case AF_INET6:
+ sock_lock_init_class_and_name(sk,
+ "slock-AF_INET6-RDMA-SIW",
+ &siw_slock_key[1],
+ "sk_lock-AF_INET6-RDMA-SIW",
+ &siw_sk_key[1]);
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ }
+#endif /* CONFIG_DEBUG_LOCK_ALLOC */
+}
+
static void siw_sk_assign_cm_upcalls(struct sock *sk)
{
struct siw_cep *cep = sk_to_cep(sk);
@@ -1394,6 +1443,7 @@ 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 +1820,7 @@ 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
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v2] RDMA/siw: reclassify sockets in order to avoid false positives from lockdep
2025-11-26 15:08 [PATCH v2] RDMA/siw: reclassify sockets in order to avoid false positives from lockdep Stefan Metzmacher
@ 2025-11-26 15:46 ` Bernard Metzler
2025-11-27 12:10 ` Leon Romanovsky
1 sibling, 0 replies; 3+ messages in thread
From: Bernard Metzler @ 2025-11-26 15:46 UTC (permalink / raw)
To: Stefan Metzmacher, linux-rdma
Cc: Jason Gunthorpe, Leon Romanovsky, netdev, linux-cifs
On 26.11.2025 16:08, 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 <bernard.metzler@linux.dev>
> Cc: Jason Gunthorpe <jgg@ziepe.ca>
> Cc: Leon Romanovsky <leon@kernel.org>
> Cc: linux-rdma@vger.kernel.org
> Cc: netdev@vger.kernel.org
> Cc: linux-cifs@vger.kernel.org
> Signed-off-by: Stefan Metzmacher <metze@samba.org>
>
> ---
>
> v2: - use CONFIG_DEBUG_LOCK_ALLOC (Bernard)
> - add a comment (Bernard)
> - AF_INET vs. AF_INET6 (Bernard)
> ---
> drivers/infiniband/sw/siw/siw_cm.c | 51 ++++++++++++++++++++++++++++++
> 1 file changed, 51 insertions(+)
>
> diff --git a/drivers/infiniband/sw/siw/siw_cm.c b/drivers/infiniband/sw/siw/siw_cm.c
> index 708b13993fdf..79dd44cd6bc3 100644
> --- a/drivers/infiniband/sw/siw/siw_cm.c
> +++ b/drivers/infiniband/sw/siw/siw_cm.c
> @@ -39,6 +39,55 @@ 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);
>
> +
> +#ifdef CONFIG_DEBUG_LOCK_ALLOC
> +/*
> + * lockdep can detect false positive circular dependencies
> + * when there are user-space socket API users or in kernel
> + * users switching between a tcp and rdma transport.
> + * Maybe also switching between siw and rxe may cause
> + * problems as per default sockets are only classified
> + * by family and not by ip protocol. And there might
> + * be different locks used between the application
> + * and the low level sockets.
> + *
> + * Problems were seen with ksmbd.ko and cifs.ko,
> + * switching transports, use git blame to find
> + * more details.
> + */
> +static struct lock_class_key siw_sk_key[2];
> +static struct lock_class_key siw_slock_key[2];
> +#endif /* CONFIG_DEBUG_LOCK_ALLOC */
> +
> +static inline void siw_reclassify_socket(struct socket *sock)
> +{
> +#ifdef CONFIG_DEBUG_LOCK_ALLOC
> + struct sock *sk = sock->sk;
> +
> + if (WARN_ON_ONCE(!sock_allow_reclassification(sk)))
> + return;
> +
> + switch (sk->sk_family) {
> + case AF_INET:
> + sock_lock_init_class_and_name(sk,
> + "slock-AF_INET-RDMA-SIW",
> + &siw_slock_key[0],
> + "sk_lock-AF_INET-RDMA-SIW",
> + &siw_sk_key[0]);
> + break;
> + case AF_INET6:
> + sock_lock_init_class_and_name(sk,
> + "slock-AF_INET6-RDMA-SIW",
> + &siw_slock_key[1],
> + "sk_lock-AF_INET6-RDMA-SIW",
> + &siw_sk_key[1]);
> + break;
> + default:
> + WARN_ON_ONCE(1);
> + }
> +#endif /* CONFIG_DEBUG_LOCK_ALLOC */
> +}
> +
> static void siw_sk_assign_cm_upcalls(struct sock *sk)
> {
> struct siw_cep *cep = sk_to_cep(sk);
> @@ -1394,6 +1443,7 @@ 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 +1820,7 @@ 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.
Thank you, looks good.
Acked-by: Bernard Metzler <bernard.metzler@linux.dev>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v2] RDMA/siw: reclassify sockets in order to avoid false positives from lockdep
2025-11-26 15:08 [PATCH v2] RDMA/siw: reclassify sockets in order to avoid false positives from lockdep Stefan Metzmacher
2025-11-26 15:46 ` Bernard Metzler
@ 2025-11-27 12:10 ` Leon Romanovsky
1 sibling, 0 replies; 3+ messages in thread
From: Leon Romanovsky @ 2025-11-27 12:10 UTC (permalink / raw)
To: linux-rdma, Stefan Metzmacher
Cc: Bernard Metzler, Jason Gunthorpe, netdev, linux-cifs
On Wed, 26 Nov 2025 16:08:42 +0100, 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.
>
> [...]
Applied, thanks!
[1/1] RDMA/siw: reclassify sockets in order to avoid false positives from lockdep
https://git.kernel.org/rdma/rdma/c/3a2c32d357db8d
Best regards,
--
Leon Romanovsky <leon@kernel.org>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2025-11-26 15:08 [PATCH v2] RDMA/siw: reclassify sockets in order to avoid false positives from lockdep Stefan Metzmacher
2025-11-26 15:46 ` Bernard Metzler
2025-11-27 12:10 ` Leon Romanovsky
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