linux-stable/net/smc
Eric Dumazet 00af2aa93b net/smc: reduce rtnl pressure in smc_pnet_create_pnetids_list()
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>
2024-03-05 15:49:35 +01:00
..
af_smc.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2024-02-15 16:20:04 -08:00
Kconfig net/smc: Fix dependency of SMC on ISM 2023-10-10 11:51:41 +02:00
Makefile net/smc: fix compile warning for smc_sysctl 2022-03-07 11:59:17 +00:00
smc.h net/smc: change the term virtual ISM to Emulated-ISM 2024-02-07 18:24:19 -08:00
smc_cdc.c net/smc: allow cdc msg send rather than drop it with NULL sndbuf_desc 2023-11-06 10:01:07 +00:00
smc_cdc.h net/smc: fix kernel panic caused by race of smc_sock 2021-12-28 12:42:45 +00:00
smc_clc.c net/smc: change the term virtual ISM to Emulated-ISM 2024-02-07 18:24:19 -08:00
smc_clc.h net/smc: change the term virtual ISM to Emulated-ISM 2024-02-07 18:24:19 -08:00
smc_close.c net/smc: put sk reference if close work was canceled 2023-11-06 10:01:07 +00:00
smc_close.h
smc_core.c net/smc: change the term virtual ISM to Emulated-ISM 2024-02-07 18:24:19 -08:00
smc_core.h net/smc: compatible with 128-bits extended GID of virtual ISM device 2023-12-26 20:24:33 +00:00
smc_diag.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2024-01-25 14:20:08 -08:00
smc_ib.c mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER 2024-01-08 15:27:15 -08:00
smc_ib.h net/smc: fix smc clc failed issue when netdevice not in init_net 2023-10-13 16:52:02 -07:00
smc_ism.c net/smc: manage system EID in SMC stack instead of ISM driver 2023-12-26 20:24:33 +00:00
smc_ism.h net/smc: change the term virtual ISM to Emulated-ISM 2024-02-07 18:24:19 -08:00
smc_llc.c net/smc: support max links per lgr negotiation in clc handshake 2023-08-19 12:46:53 +01:00
smc_llc.h net/smc: Introduce a specific sysctl for TEST_LINK time 2022-09-22 12:58:21 +02:00
smc_netlink.c genetlink: start to validate reserved header bytes 2022-08-29 12:47:15 +01:00
smc_netlink.h net/smc: add support for user defined EIDs 2021-09-14 12:49:10 +01:00
smc_netns.h
smc_pnet.c net/smc: reduce rtnl pressure in smc_pnet_create_pnetids_list() 2024-03-05 15:49:35 +01:00
smc_pnet.h net/smc: Use a mutex for locking "struct smc_pnettable" 2022-02-24 09:09:33 -08:00
smc_rx.c net: deal with most data-races in sk_wait_event() 2023-05-10 10:03:32 +01:00
smc_rx.h
smc_stats.c smc: Drop smc_sendpage() in favour of smc_sendmsg() + MSG_SPLICE_PAGES 2023-06-24 15:50:12 -07:00
smc_stats.h net/smc: Fix pos miscalculation in statistics 2023-10-11 10:36:35 +01:00
smc_sysctl.c net/smc: add sysctl for max conns per lgr for SMC-R v2.1 2023-11-24 12:13:14 +00:00
smc_sysctl.h net/smc: add sysctl for max conns per lgr for SMC-R v2.1 2023-11-24 12:13:14 +00:00
smc_tracepoint.c net/smc: Introduce tracepoint for smcr link down 2021-11-01 13:39:14 +00:00
smc_tracepoint.h net/smc: Add net namespace for tracepoints 2022-01-02 12:07:39 +00:00
smc_tx.c net/smc: remove unneeded atomic operations in smc_tx_sndbuf_nonempty 2023-11-24 15:00:47 +00:00
smc_tx.h smc: Drop smc_sendpage() in favour of smc_sendmsg() + MSG_SPLICE_PAGES 2023-06-24 15:50:12 -07:00
smc_wr.c net/smc: Use percpu ref for wr tx reference 2023-03-17 08:59:01 +00:00
smc_wr.h net/smc: Use percpu ref for wr tx reference 2023-03-17 08:59:01 +00:00