kernel.git/net/smc, branch linux-5.4.y

net/smc: check sndbuf_space again after NOSPACE flag is set in smc_poll

2025-01-09T12:23:27Z

[ Upstream commit 679e9ddcf90dbdf98aaaa71a492454654b627bcb ] When application sending data more than sndbuf_space, there have chances application will sleep in epoll_wait, and will never be wakeup again. This is caused by a race between smc_poll and smc_cdc_tx_handler. application tasklet smc_tx_sendmsg(len > sndbuf_space) | epoll_wait for EPOLL_OUT,timeout=0 | smc_poll | if (!smc->conn.sndbuf_space) | | smc_cdc_tx_handler | atomic_add sndbuf_space | smc_tx_sndbuf_nonfull | if (!test_bit SOCK_NOSPACE) | do not sk_write_space; set_bit SOCK_NOSPACE; | return mask=0; | Application will sleep in epoll_wait as smc_poll returns 0. And smc_cdc_tx_handler will not call sk_write_space because the SOCK_NOSPACE has not be set. If there is no inflight cdc msg, sk_write_space will not be called any more, and application will sleep in epoll_wait forever. So check sndbuf_space again after NOSPACE flag is set to break the race. Fixes: 8dce2786a290 ("net/smc: smc_poll improvements") Signed-off-by: Guangguan Wang Suggested-by: Paolo Abeni Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

net/smc: set rmb's SG_MAX_SINGLE_ALLOC limitation only when CONFIG_ARCH_NO_SG_CHAIN is defined

2024-08-19T03:33:28Z

[ Upstream commit 3ac14b9dfbd345e891d48d89f6c2fa519848f0f4 ] SG_MAX_SINGLE_ALLOC is used to limit maximum number of entries that will be allocated in one piece of scatterlist. When the entries of scatterlist exceeds SG_MAX_SINGLE_ALLOC, sg chain will be used. From commit 7c703e54cc71 ("arch: switch the default on ARCH_HAS_SG_CHAIN"), we can know that the macro CONFIG_ARCH_NO_SG_CHAIN is used to identify whether sg chain is supported. So, SMC-R's rmb buffer should be limited by SG_MAX_SINGLE_ALLOC only when the macro CONFIG_ARCH_NO_SG_CHAIN is defined. Fixes: a3fe3d01bd0d ("net/smc: introduce sg-logic for RMBs") Signed-off-by: Guangguan Wang Co-developed-by: Wen Gu Signed-off-by: Wen Gu Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

net/smc: Allow SMC-D 1MB DMB allocations

2024-08-19T03:33:28Z

[ Upstream commit 67161779a9ea926fccee8de047ae66cbd3482b91 ] Commit a3fe3d01bd0d7 ("net/smc: introduce sg-logic for RMBs") introduced a restriction for RMB allocations as used by SMC-R. However, SMC-D does not use scatter-gather lists to back its DMBs, yet it was limited by this restriction, still. This patch exempts SMC, but limits allocations to the maximum RMB/DMB size respectively. Signed-off-by: Stefan Raspl Signed-off-by: Guvenc Gulce Signed-off-by: David S. Miller Stable-dep-of: 3ac14b9dfbd3 ("net/smc: set rmb's SG_MAX_SINGLE_ALLOC limitation only when CONFIG_ARCH_NO_SG_CHAIN is defined") Signed-off-by: Sasha Levin

net/smc: fix illegal rmb_desc access in SMC-D connection dump

2024-02-23T07:24:50Z

[ Upstream commit 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 -H 'Connection: Close' - 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: ? __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 Reviewed-by: Dust Li Reviewed-by: Wenjia Zhang Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

net/smc: fix dangling sock under state SMC_APPFINCLOSEWAIT

2023-11-20T09:30:16Z

[ Upstream commit 5211c9729484c923f8d2e06bd29f9322cc42bb8f ] Considering scenario: smc_cdc_rx_handler __smc_release sock_set_flag smc_close_active() sock_set_flag __set_bit(DEAD) __set_bit(DONE) Dues to __set_bit is not atomic, the DEAD or DONE might be lost. if the DEAD flag lost, the state SMC_CLOSED will be never be reached in smc_close_passive_work: if (sock_flag(sk, SOCK_DEAD) && smc_close_sent_any_close(conn)) { sk->sk_state = SMC_CLOSED; } else { /* just shutdown, but not yet closed locally */ sk->sk_state = SMC_APPFINCLOSEWAIT; } Replace sock_set_flags or __set_bit to set_bit will fix this problem. Since set_bit is atomic. Fixes: b38d732477e4 ("smc: socket closing and linkgroup cleanup") Signed-off-by: D. Wythe Reviewed-by: Dust Li Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

net/smc: fix fallback failed while sendmsg with fastopen

2023-03-17T07:32:51Z

[ Upstream commit ce7ca794712f186da99719e8b4e97bd5ddbb04c3 ] Before determining whether the msg has unsupported options, it has been prematurely terminated by the wrong status check. For the application, the general usages of MSG_FASTOPEN likes fd = socket(...) /* rather than connect */ sendto(fd, data, len, MSG_FASTOPEN) Hence, We need to check the flag before state check, because the sock state here is always SMC_INIT when applications tries MSG_FASTOPEN. Once we found unsupported options, fallback it to TCP. Fixes: ee9dfbef02d1 ("net/smc: handle sockopts forcing fallback") Signed-off-by: D. Wythe Signed-off-by: Simon Horman v2 -> v1: Optimize code style Reviewed-by: Tony Lu Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

net/smc: Remove redundant refcount increase

2022-09-15T10:04:50Z

[ Upstream commit a8424a9b4522a3ab9f32175ad6d848739079071f ] For passive connections, the refcount increment has been done in smc_clcsock_accept()-->smc_sock_alloc(). Fixes: 3b2dec2603d5 ("net/smc: restructure client and server code in af_smc") Signed-off-by: Yacan Liu Reviewed-by: Tony Lu Link: https://lore.kernel.org/r/20220830152314.838736-1-liuyacan@corp.netease.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

net/smc: postpone sk_refcnt increment in connect()

2022-06-14T16:11:39Z

[ Upstream commit 75c1edf23b95a9c66923d9269d8e86e4dbde151f ] Same trigger condition as commit 86434744. When setsockopt runs in parallel to a connect(), and switch the socket into fallback mode. Then the sk_refcnt is incremented in smc_connect(), but its state stay in SMC_INIT (NOT SMC_ACTIVE). This cause the corresponding sk_refcnt decrement in __smc_release() will not be performed. Fixes: 86434744fedf ("net/smc: add fallback check to connect()") Signed-off-by: liuyacan Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

net/smc: non blocking recvmsg() return -EAGAIN when no data and signal_pending

2022-05-18T07:47:25Z

[ Upstream commit f3c46e41b32b6266cf60b0985c61748f53bf1c61 ] Non blocking sendmsg will return -EAGAIN when any signal pending and no send space left, while non blocking recvmsg return -EINTR when signal pending and no data received. This may makes confused. As TCP returns -EAGAIN in the conditions described above. Align the behavior of smc with TCP. Fixes: 846e344eb722 ("net/smc: add receive timeout check") Signed-off-by: Guangguan Wang Reviewed-by: Tony Lu Acked-by: Karsten Graul Link: https://lore.kernel.org/r/20220512030820.73848-1-guangguan.wang@linux.alibaba.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net/smc: sync err code when tcp connection was refused

2022-05-09T07:03:25Z

[ Upstream commit 4e2e65e2e56c6ceb4ea1719360080c0af083229e ] In the current implementation, when TCP initiates a connection to an unavailable [ip,port], ECONNREFUSED will be stored in the TCP socket, but SMC will not. However, some apps (like curl) use getsockopt(,,SO_ERROR,,) to get the error information, which makes them miss the error message and behave strangely. Fixes: 50717a37db03 ("net/smc: nonblocking connect rework") Signed-off-by: liuyacan Reviewed-by: Tony Lu Acked-by: Karsten Graul Signed-off-by: David S. Miller Signed-off-by: Sasha Levin