linux.git/net/smc, branch v6.9 Linux kernel source tree net/smc: fix neighbour and rtable leak in smc_ib_find_route() 2024-05-09T08:03:43+00:00 Wen Gu guwen@linux.alibaba.com 2024-05-07T12:53:31+00:00 2ddc0dd7fec86ee53b8928a5cca5fbddd4fc7c06 In smc_ib_find_route(), the neighbour found by neigh_lookup() and rtable resolved by ip_route_output_flow() are not released or put before return. It may cause the refcount leak, so fix it. Link: https://lore.kernel.org/r/20240506015439.108739-1-guwen@linux.alibaba.com Fixes: e5c4744cfb59 ("net/smc: add SMC-Rv2 connection establishment") Signed-off-by: Wen Gu <guwen@linux.alibaba.com> Link: https://lore.kernel.org/r/20240507125331.2808-1-guwen@linux.alibaba.com Signed-off-by: Paolo Abeni <pabeni@redhat.com> 
In smc_ib_find_route(), the neighbour found by neigh_lookup() and rtable
resolved by ip_route_output_flow() are not released or put before return.
It may cause the refcount leak, so fix it.

Link: https://lore.kernel.org/r/20240506015439.108739-1-guwen@linux.alibaba.com
Fixes: e5c4744cfb59 ("net/smc: add SMC-Rv2 connection establishment")
Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Link: https://lore.kernel.org/r/20240507125331.2808-1-guwen@linux.alibaba.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
net/smc: reduce rtnl pressure in smc_pnet_create_pnetids_list() 2024-03-05T14:49:35+00:00 Eric Dumazet edumazet@google.com 2024-03-02T10:07:44+00:00 00af2aa93b76b1bade471ad0d0525d4d29ca5cc0 Many syzbot reports show extreme rtnl pressure, and many of them hint that smc acquires rtnl in netns creation for no good reason [1] This patch returns early from smc_pnet_net_init() if there is no netdevice yet. I am not even sure why smc_pnet_create_pnetids_list() even exists, because smc_pnet_netdev_event() is also calling smc_pnet_add_base_pnetid() when handling NETDEV_UP event. [1] extract of typical syzbot reports 2 locks held by syz-executor.3/12252: #0: ffffffff8f369610 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c7/0x7b0 net/core/net_namespace.c:491 #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_create_pnetids_list net/smc/smc_pnet.c:809 [inline] #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_net_init+0x10a/0x1e0 net/smc/smc_pnet.c:878 2 locks held by syz-executor.4/12253: #0: ffffffff8f369610 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c7/0x7b0 net/core/net_namespace.c:491 #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_create_pnetids_list net/smc/smc_pnet.c:809 [inline] #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_net_init+0x10a/0x1e0 net/smc/smc_pnet.c:878 2 locks held by syz-executor.1/12257: #0: ffffffff8f369610 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c7/0x7b0 net/core/net_namespace.c:491 #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_create_pnetids_list net/smc/smc_pnet.c:809 [inline] #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_net_init+0x10a/0x1e0 net/smc/smc_pnet.c:878 2 locks held by syz-executor.2/12261: #0: ffffffff8f369610 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c7/0x7b0 net/core/net_namespace.c:491 #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_create_pnetids_list net/smc/smc_pnet.c:809 [inline] #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_net_init+0x10a/0x1e0 net/smc/smc_pnet.c:878 2 locks held by syz-executor.0/12265: #0: ffffffff8f369610 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c7/0x7b0 net/core/net_namespace.c:491 #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_create_pnetids_list net/smc/smc_pnet.c:809 [inline] #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_net_init+0x10a/0x1e0 net/smc/smc_pnet.c:878 2 locks held by syz-executor.3/12268: #0: ffffffff8f369610 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c7/0x7b0 net/core/net_namespace.c:491 #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_create_pnetids_list net/smc/smc_pnet.c:809 [inline] #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_net_init+0x10a/0x1e0 net/smc/smc_pnet.c:878 2 locks held by syz-executor.4/12271: #0: ffffffff8f369610 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c7/0x7b0 net/core/net_namespace.c:491 #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_create_pnetids_list net/smc/smc_pnet.c:809 [inline] #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_net_init+0x10a/0x1e0 net/smc/smc_pnet.c:878 2 locks held by syz-executor.1/12274: #0: ffffffff8f369610 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c7/0x7b0 net/core/net_namespace.c:491 #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_create_pnetids_list net/smc/smc_pnet.c:809 [inline] #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_net_init+0x10a/0x1e0 net/smc/smc_pnet.c:878 2 locks held by syz-executor.2/12280: #0: ffffffff8f369610 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c7/0x7b0 net/core/net_namespace.c:491 #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_create_pnetids_list net/smc/smc_pnet.c:809 [inline] #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_net_init+0x10a/0x1e0 net/smc/smc_pnet.c:878 Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Wenjia Zhang <wenjia@linux.ibm.com> Cc: Jan Karcher <jaka@linux.ibm.com> Cc: "D. Wythe" <alibuda@linux.alibaba.com> Cc: Tony Lu <tonylu@linux.alibaba.com> Cc: Wen Gu <guwen@linux.alibaba.com> Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com> Link: https://lore.kernel.org/r/20240302100744.3868021-1-edumazet@google.com Signed-off-by: Paolo Abeni <pabeni@redhat.com> 
Many syzbot reports show extreme rtnl pressure, and many of them hint
that smc acquires rtnl in netns creation for no good reason [1]

This patch returns early from smc_pnet_net_init()
if there is no netdevice yet.

I am not even sure why smc_pnet_create_pnetids_list() even exists,
because smc_pnet_netdev_event() is also calling
smc_pnet_add_base_pnetid() when handling NETDEV_UP event.

[1] extract of typical syzbot reports

2 locks held by syz-executor.3/12252:
  #0: ffffffff8f369610 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c7/0x7b0 net/core/net_namespace.c:491
  #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_create_pnetids_list net/smc/smc_pnet.c:809 [inline]
  #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_net_init+0x10a/0x1e0 net/smc/smc_pnet.c:878
2 locks held by syz-executor.4/12253:
  #0: ffffffff8f369610 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c7/0x7b0 net/core/net_namespace.c:491
  #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_create_pnetids_list net/smc/smc_pnet.c:809 [inline]
  #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_net_init+0x10a/0x1e0 net/smc/smc_pnet.c:878
2 locks held by syz-executor.1/12257:
  #0: ffffffff8f369610 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c7/0x7b0 net/core/net_namespace.c:491
  #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_create_pnetids_list net/smc/smc_pnet.c:809 [inline]
  #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_net_init+0x10a/0x1e0 net/smc/smc_pnet.c:878
2 locks held by syz-executor.2/12261:
  #0: ffffffff8f369610 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c7/0x7b0 net/core/net_namespace.c:491
  #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_create_pnetids_list net/smc/smc_pnet.c:809 [inline]
  #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_net_init+0x10a/0x1e0 net/smc/smc_pnet.c:878
2 locks held by syz-executor.0/12265:
  #0: ffffffff8f369610 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c7/0x7b0 net/core/net_namespace.c:491
  #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_create_pnetids_list net/smc/smc_pnet.c:809 [inline]
  #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_net_init+0x10a/0x1e0 net/smc/smc_pnet.c:878
2 locks held by syz-executor.3/12268:
  #0: ffffffff8f369610 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c7/0x7b0 net/core/net_namespace.c:491
  #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_create_pnetids_list net/smc/smc_pnet.c:809 [inline]
  #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_net_init+0x10a/0x1e0 net/smc/smc_pnet.c:878
2 locks held by syz-executor.4/12271:
  #0: ffffffff8f369610 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c7/0x7b0 net/core/net_namespace.c:491
  #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_create_pnetids_list net/smc/smc_pnet.c:809 [inline]
  #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_net_init+0x10a/0x1e0 net/smc/smc_pnet.c:878
2 locks held by syz-executor.1/12274:
  #0: ffffffff8f369610 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c7/0x7b0 net/core/net_namespace.c:491
  #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_create_pnetids_list net/smc/smc_pnet.c:809 [inline]
  #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_net_init+0x10a/0x1e0 net/smc/smc_pnet.c:878
2 locks held by syz-executor.2/12280:
  #0: ffffffff8f369610 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c7/0x7b0 net/core/net_namespace.c:491
  #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_create_pnetids_list net/smc/smc_pnet.c:809 [inline]
  #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_net_init+0x10a/0x1e0 net/smc/smc_pnet.c:878

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Wenjia Zhang <wenjia@linux.ibm.com>
Cc: Jan Karcher <jaka@linux.ibm.com>
Cc: "D. Wythe" <alibuda@linux.alibaba.com>
Cc: Tony Lu <tonylu@linux.alibaba.com>
Cc: Wen Gu <guwen@linux.alibaba.com>
Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com>
Link: https://lore.kernel.org/r/20240302100744.3868021-1-edumazet@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2024-02-16T00:20:04+00:00 Jakub Kicinski kuba@kernel.org 2024-02-15T22:01:43+00:00 73be9a3aabdd976123e7f05dd20dbcf131347e84 Cross-merge networking fixes after downstream PR. No conflicts. Adjacent changes: net/core/dev.c 9f30831390ed ("net: add rcu safety to rtnl_prop_list_size()") 723de3ebef03 ("net: free altname using an RCU callback") net/unix/garbage.c 11498715f266 ("af_unix: Remove io_uring code for GC.") 25236c91b5ab ("af_unix: Fix task hung while purging oob_skb in GC.") drivers/net/ethernet/renesas/ravb_main.c ed4adc07207d ("net: ravb: Count packets instead of descriptors in GbEth RX path" ) c2da9408579d ("ravb: Add Rx checksum offload support for GbEth") net/mptcp/protocol.c bdd70eb68913 ("mptcp: drop the push_pending field") 28e5c1380506 ("mptcp: annotate lockless accesses around read-mostly fields") Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Cross-merge networking fixes after downstream PR.

No conflicts.

Adjacent changes:

net/core/dev.c
  9f30831390ed ("net: add rcu safety to rtnl_prop_list_size()")
  723de3ebef03 ("net: free altname using an RCU callback")

net/unix/garbage.c
  11498715f266 ("af_unix: Remove io_uring code for GC.")
  25236c91b5ab ("af_unix: Fix task hung while purging oob_skb in GC.")

drivers/net/ethernet/renesas/ravb_main.c
  ed4adc07207d ("net: ravb: Count packets instead of descriptors in GbEth RX path"
)
  c2da9408579d ("ravb: Add Rx checksum offload support for GbEth")

net/mptcp/protocol.c
  bdd70eb68913 ("mptcp: drop the push_pending field")
  28e5c1380506 ("mptcp: annotate lockless accesses around read-mostly fields")

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net: smc: fix spurious error message from __sock_release() 2024-02-14T10:56:02+00:00 Dmitry Antipov dmantipov@yandex.ru 2024-02-12T14:34:02+00:00 6cf9ff463317217d95732a6cce6fbdd12508921a Commit 67f562e3e147 ("net/smc: transfer fasync_list in case of fallback") leaves the socket's fasync list pointer within a container socket as well. When the latter is destroyed, '__sock_release()' warns about its non-empty fasync list, which is a dangling pointer to previously freed fasync list of an underlying TCP socket. Fix this spurious warning by nullifying fasync list of a container socket. Fixes: 67f562e3e147 ("net/smc: transfer fasync_list in case of fallback") Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru> Signed-off-by: David S. Miller <davem@davemloft.net> 
Commit 67f562e3e147 ("net/smc: transfer fasync_list in case of fallback")
leaves the socket's fasync list pointer within a container socket as well.
When the latter is destroyed, '__sock_release()' warns about its non-empty
fasync list, which is a dangling pointer to previously freed fasync list
of an underlying TCP socket. Fix this spurious warning by nullifying
fasync list of a container socket.

Fixes: 67f562e3e147 ("net/smc: transfer fasync_list in case of fallback")
Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/smc: change the term virtual ISM to Emulated-ISM 2024-02-08T02:24:19+00:00 Wen Gu guwen@linux.alibaba.com 2024-02-05T03:33:17+00:00 b27696cd8fcc0ace1b2dfd81b7bff824a30b1fd1 According to latest release of SMCv2.1[1], the term 'virtual ISM' has been changed to 'Emulated-ISM' to avoid the ambiguity of the word 'virtual' in different contexts. So the names or comments in the code need be modified accordingly. [1] https://www.ibm.com/support/pages/node/7112343 Signed-off-by: Wen Gu <guwen@linux.alibaba.com> Reviewed-by: Simon Horman <horms@kernel.org> Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com> Link: https://lore.kernel.org/r/20240205033317.127269-1-guwen@linux.alibaba.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
According to latest release of SMCv2.1[1], the term 'virtual ISM' has
been changed to 'Emulated-ISM' to avoid the ambiguity of the word
'virtual' in different contexts. So the names or comments in the code
need be modified accordingly.

[1] https://www.ibm.com/support/pages/node/7112343

Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com>
Link: https://lore.kernel.org/r/20240205033317.127269-1-guwen@linux.alibaba.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2024-02-01T23:12:37+00:00 Jakub Kicinski kuba@kernel.org 2024-02-01T22:33:26+00:00 cf244463a286ea57ea7e63c33614d302f776e62e Cross-merge networking fixes after downstream PR. No conflicts or adjacent changes. Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Cross-merge networking fixes after downstream PR.

No conflicts or adjacent changes.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net/smc: fix incorrect SMC-D link group matching logic 2024-01-26T22:06:05+00:00 Wen Gu guwen@linux.alibaba.com 2024-01-25T12:39:16+00:00 c3dfcdb65ec1a4813ec1e0871c52c671ba9c71ac The logic to determine if SMC-D link group matches is incorrect. The correct logic should be that it only returns true when the GID is the same, and the SMC-D device is the same and the extended GID is the same (in the case of virtual ISM). It can be fixed by adding brackets around the conditional (or ternary) operator expression. But for better readability and maintainability, it has been changed to an if-else statement. Reported-by: Matthew Rosato <mjrosato@linux.ibm.com> Closes: https://lore.kernel.org/r/13579588-eb9d-4626-a063-c0b77ed80f11@linux.ibm.com Fixes: b40584d14570 ("net/smc: compatible with 128-bits extended GID of virtual ISM device") Link: https://lore.kernel.org/r/13579588-eb9d-4626-a063-c0b77ed80f11@linux.ibm.com Signed-off-by: Wen Gu <guwen@linux.alibaba.com> Reviewed-by: Alexandra Winter <wintera@linux.ibm.com> Link: https://lore.kernel.org/r/20240125123916.77928-1-guwen@linux.alibaba.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
The logic to determine if SMC-D link group matches is incorrect. The
correct logic should be that it only returns true when the GID is the
same, and the SMC-D device is the same and the extended GID is the same
(in the case of virtual ISM).

It can be fixed by adding brackets around the conditional (or ternary)
operator expression. But for better readability and maintainability, it
has been changed to an if-else statement.

Reported-by: Matthew Rosato <mjrosato@linux.ibm.com>
Closes: https://lore.kernel.org/r/13579588-eb9d-4626-a063-c0b77ed80f11@linux.ibm.com
Fixes: b40584d14570 ("net/smc: compatible with 128-bits extended GID of virtual ISM device")
Link: https://lore.kernel.org/r/13579588-eb9d-4626-a063-c0b77ed80f11@linux.ibm.com
Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Reviewed-by: Alexandra Winter <wintera@linux.ibm.com>
Link: https://lore.kernel.org/r/20240125123916.77928-1-guwen@linux.alibaba.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2024-01-25T22:20:08+00:00 Jakub Kicinski kuba@kernel.org 2024-01-25T22:00:54+00:00 06f609b3119876b42f19fdb690b10896d3c648e6 Cross-merge networking fixes after downstream PR. No conflicts or adjacent changes. Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Cross-merge networking fixes after downstream PR.

No conflicts or adjacent changes.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
sock_diag: add module pointer to "struct sock_diag_handler" 2024-01-23T14:13:54+00:00 Eric Dumazet edumazet@google.com 2024-01-22T11:25:59+00:00 114b4bb1cc19239b272d52ebbe156053483fe2f8 Following patch is going to use RCU instead of sock_diag_table_mutex acquisition. This patch is a preparation, no change of behavior yet. Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Guillaume Nault <gnault@redhat.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com> 
Following patch is going to use RCU instead of
sock_diag_table_mutex acquisition.

This patch is a preparation, no change of behavior yet.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
net/smc: fix illegal rmb_desc access in SMC-D connection dump 2024-01-19T12:04:17+00:00 Wen Gu guwen@linux.alibaba.com 2024-01-18T04:32:10+00:00 dbc153fd3c142909e564bb256da087e13fbf239c A crash was found when dumping SMC-D connections. It can be reproduced by following steps: - run nginx/wrk test: smc_run nginx smc_run wrk -t 16 -c 1000 -d <duration> -H 'Connection: Close' <URL> - continuously dump SMC-D connections in parallel: watch -n 1 'smcss -D' BUG: kernel NULL pointer dereference, address: 0000000000000030 CPU: 2 PID: 7204 Comm: smcss Kdump: loaded Tainted: G E 6.7.0+ #55 RIP: 0010:__smc_diag_dump.constprop.0+0x5e5/0x620 [smc_diag] Call Trace: <TASK> ? __die+0x24/0x70 ? page_fault_oops+0x66/0x150 ? exc_page_fault+0x69/0x140 ? asm_exc_page_fault+0x26/0x30 ? __smc_diag_dump.constprop.0+0x5e5/0x620 [smc_diag] ? __kmalloc_node_track_caller+0x35d/0x430 ? __alloc_skb+0x77/0x170 smc_diag_dump_proto+0xd0/0xf0 [smc_diag] smc_diag_dump+0x26/0x60 [smc_diag] netlink_dump+0x19f/0x320 __netlink_dump_start+0x1dc/0x300 smc_diag_handler_dump+0x6a/0x80 [smc_diag] ? __pfx_smc_diag_dump+0x10/0x10 [smc_diag] sock_diag_rcv_msg+0x121/0x140 ? __pfx_sock_diag_rcv_msg+0x10/0x10 netlink_rcv_skb+0x5a/0x110 sock_diag_rcv+0x28/0x40 netlink_unicast+0x22a/0x330 netlink_sendmsg+0x1f8/0x420 __sock_sendmsg+0xb0/0xc0 ____sys_sendmsg+0x24e/0x300 ? copy_msghdr_from_user+0x62/0x80 ___sys_sendmsg+0x7c/0xd0 ? __do_fault+0x34/0x160 ? do_read_fault+0x5f/0x100 ? do_fault+0xb0/0x110 ? __handle_mm_fault+0x2b0/0x6c0 __sys_sendmsg+0x4d/0x80 do_syscall_64+0x69/0x180 entry_SYSCALL_64_after_hwframe+0x6e/0x76 It is possible that the connection is in process of being established when we dump it. Assumed that the connection has been registered in a link group by smc_conn_create() but the rmb_desc has not yet been initialized by smc_buf_create(), thus causing the illegal access to conn->rmb_desc. So fix it by checking before dump. Fixes: 4b1b7d3b30a6 ("net/smc: add SMC-D diag support") Signed-off-by: Wen Gu <guwen@linux.alibaba.com> Reviewed-by: Dust Li <dust.li@linux.alibaba.com> Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
A crash was found when dumping SMC-D connections. It can be reproduced
by following steps:

- run nginx/wrk test:
  smc_run nginx
  smc_run wrk -t 16 -c 1000 -d <duration> -H 'Connection: Close' <URL>

- continuously dump SMC-D connections in parallel:
  watch -n 1 'smcss -D'

 BUG: kernel NULL pointer dereference, address: 0000000000000030
 CPU: 2 PID: 7204 Comm: smcss Kdump: loaded Tainted: G	E      6.7.0+ #55
 RIP: 0010:__smc_diag_dump.constprop.0+0x5e5/0x620 [smc_diag]
 Call Trace:
  <TASK>
  ? __die+0x24/0x70
  ? page_fault_oops+0x66/0x150
  ? exc_page_fault+0x69/0x140
  ? asm_exc_page_fault+0x26/0x30
  ? __smc_diag_dump.constprop.0+0x5e5/0x620 [smc_diag]
  ? __kmalloc_node_track_caller+0x35d/0x430
  ? __alloc_skb+0x77/0x170
  smc_diag_dump_proto+0xd0/0xf0 [smc_diag]
  smc_diag_dump+0x26/0x60 [smc_diag]
  netlink_dump+0x19f/0x320
  __netlink_dump_start+0x1dc/0x300
  smc_diag_handler_dump+0x6a/0x80 [smc_diag]
  ? __pfx_smc_diag_dump+0x10/0x10 [smc_diag]
  sock_diag_rcv_msg+0x121/0x140
  ? __pfx_sock_diag_rcv_msg+0x10/0x10
  netlink_rcv_skb+0x5a/0x110
  sock_diag_rcv+0x28/0x40
  netlink_unicast+0x22a/0x330
  netlink_sendmsg+0x1f8/0x420
  __sock_sendmsg+0xb0/0xc0
  ____sys_sendmsg+0x24e/0x300
  ? copy_msghdr_from_user+0x62/0x80
  ___sys_sendmsg+0x7c/0xd0
  ? __do_fault+0x34/0x160
  ? do_read_fault+0x5f/0x100
  ? do_fault+0xb0/0x110
  ? __handle_mm_fault+0x2b0/0x6c0
  __sys_sendmsg+0x4d/0x80
  do_syscall_64+0x69/0x180
  entry_SYSCALL_64_after_hwframe+0x6e/0x76

It is possible that the connection is in process of being established
when we dump it. Assumed that the connection has been registered in a
link group by smc_conn_create() but the rmb_desc has not yet been
initialized by smc_buf_create(), thus causing the illegal access to
conn->rmb_desc. So fix it by checking before dump.

Fixes: 4b1b7d3b30a6 ("net/smc: add SMC-D diag support")
Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Reviewed-by: Dust Li <dust.li@linux.alibaba.com>
Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>