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2022-11-02net/smc: Fix possible leaked pernet namespace in smc_init()Chen Zhongjin1-2/+4
In smc_init(), register_pernet_subsys(&smc_net_stat_ops) is called without any error handling. If it fails, registering of &smc_net_ops won't be reverted. And if smc_nl_init() fails, &smc_net_stat_ops itself won't be reverted. This leaves wild ops in subsystem linkedlist and when another module tries to call register_pernet_operations() it triggers page fault: BUG: unable to handle page fault for address: fffffbfff81b964c RIP: 0010:register_pernet_operations+0x1b9/0x5f0 Call Trace: <TASK> register_pernet_subsys+0x29/0x40 ebtables_init+0x58/0x1000 [ebtables] ... Fixes: 194730a9beb5 ("net/smc: Make SMC statistics network namespace aware") Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com> Reviewed-by: Tony Lu <tonylu@linux.alibaba.com> Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com> Link: https://lore.kernel.org/r/20221101093722.127223-1-chenzhongjin@huawei.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-09-27net/smc: Support SO_REUSEPORTTony Lu1-0/+1
This enables SO_REUSEPORT [1] for clcsock when it is set on smc socket, so that some applications which uses it can be transparently replaced with SMC. Also, this helps improve load distribution. Here is a simple test of NGINX + wrk with SMC. The CPU usage is collected on NGINX (server) side as below. Disable SO_REUSEPORT: 05:15:33 PM CPU %usr %nice %sys %iowait %irq %soft %steal %guest %gnice %idle 05:15:34 PM all 7.02 0.00 11.86 0.00 2.04 8.93 0.00 0.00 0.00 70.15 05:15:34 PM 0 0.00 0.00 0.00 0.00 16.00 70.00 0.00 0.00 0.00 14.00 05:15:34 PM 1 11.58 0.00 22.11 0.00 0.00 0.00 0.00 0.00 0.00 66.32 05:15:34 PM 2 1.00 0.00 1.00 0.00 0.00 0.00 0.00 0.00 0.00 98.00 05:15:34 PM 3 16.84 0.00 30.53 0.00 0.00 0.00 0.00 0.00 0.00 52.63 05:15:34 PM 4 28.72 0.00 44.68 0.00 0.00 0.00 0.00 0.00 0.00 26.60 05:15:34 PM 5 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00 05:15:34 PM 6 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00 05:15:34 PM 7 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00 Enable SO_REUSEPORT: 05:15:20 PM CPU %usr %nice %sys %iowait %irq %soft %steal %guest %gnice %idle 05:15:21 PM all 8.56 0.00 14.40 0.00 2.20 9.86 0.00 0.00 0.00 64.98 05:15:21 PM 0 0.00 0.00 4.08 0.00 14.29 76.53 0.00 0.00 0.00 5.10 05:15:21 PM 1 9.09 0.00 16.16 0.00 1.01 0.00 0.00 0.00 0.00 73.74 05:15:21 PM 2 9.38 0.00 16.67 0.00 1.04 0.00 0.00 0.00 0.00 72.92 05:15:21 PM 3 10.42 0.00 17.71 0.00 1.04 0.00 0.00 0.00 0.00 70.83 05:15:21 PM 4 9.57 0.00 15.96 0.00 0.00 0.00 0.00 0.00 0.00 74.47 05:15:21 PM 5 9.18 0.00 15.31 0.00 0.00 1.02 0.00 0.00 0.00 74.49 05:15:21 PM 6 8.60 0.00 15.05 0.00 0.00 0.00 0.00 0.00 0.00 76.34 05:15:21 PM 7 12.37 0.00 14.43 0.00 0.00 0.00 0.00 0.00 0.00 73.20 Using SO_REUSEPORT helps the load distribution of NGINX be more balanced. [1] https://man7.org/linux/man-pages/man7/socket.7.html Signed-off-by: Tony Lu <tonylu@linux.alibaba.com> Acked-by: Wenjia Zhang <wenjia@linux.ibm.com> Link: https://lore.kernel.org/r/20220922121906.72406-1-tonylu@linux.alibaba.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2022-09-22net/smc: Unbind r/w buffer size from clcsock and make them tunableTony Lu1-3/+2
Currently, SMC uses smc->sk.sk_{rcv|snd}buf to create buffers for send buffer and RMB. And the values of buffer size are from tcp_{w|r}mem in clcsock. The buffer size from TCP socket doesn't fit SMC well. Generally, buffers are usually larger than TCP for SMC-R/-D to get higher performance, for they are different underlay devices and paths. So this patch unbinds buffer size from TCP, and introduces two sysctl knobs to tune them independently. Also, these knobs are per net namespace and work for containers. Signed-off-by: Tony Lu <tonylu@linux.alibaba.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2022-09-01net/smc: Remove redundant refcount increaseYacan Liu1-1/+0
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 <liuyacan@corp.netease.com> Reviewed-by: Tony Lu <tonylu@linux.alibaba.com> Link: https://lore.kernel.org/r/20220830152314.838736-1-liuyacan@corp.netease.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2022-07-27net/smc: Enable module load on netlink usageStefan Raspl1-0/+1
Previously, the smc and smc_diag modules were automatically loaded as dependencies of the ism module whenever an ISM device was present. With the pending rework of the ISM API, the smc module will no longer automatically be loaded in presence of an ISM device. Usage of an AF_SMC socket will still trigger loading of the smc modules, but usage of a netlink socket will not. This is addressed by setting the correct module aliases. Signed-off-by: Stefan Raspl <raspl@linux.ibm.com> Signed-off-by: Wenjia Zhang < wenjia@linux.ibm.com> Reviewed-by: Tony Lu <tonylu@linux.alibaba.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-07-18net/smc: Allow virtually contiguous sndbufs or RMBs for SMC-RWen Gu1-8/+58
On long-running enterprise production servers, high-order contiguous memory pages are usually very rare and in most cases we can only get fragmented pages. When replacing TCP with SMC-R in such production scenarios, attempting to allocate high-order physically contiguous sndbufs and RMBs may result in frequent memory compaction, which will cause unexpected hung issue and further stability risks. So this patch is aimed to allow SMC-R link group to use virtually contiguous sndbufs and RMBs to avoid potential issues mentioned above. Whether to use physically or virtually contiguous buffers can be set by sysctl smcr_buf_type. Note that using virtually contiguous buffers will bring an acceptable performance regression, which can be mainly divided into two parts: 1) regression in data path, which is brought by additional address translation of sndbuf by RNIC in Tx. But in general, translating address through MTT is fast. Taking 256KB sndbuf and RMB as an example, the comparisons in qperf latency and bandwidth test with physically and virtually contiguous buffers are as follows: - client: smc_run taskset -c <cpu> qperf <server> -oo msg_size:1:64K:*2\ -t 5 -vu tcp_{bw|lat} - server: smc_run taskset -c <cpu> qperf [latency] msgsize tcp smcr smcr-use-virt-buf 1 11.17 us 7.56 us 7.51 us (-0.67%) 2 10.65 us 7.74 us 7.56 us (-2.31%) 4 11.11 us 7.52 us 7.59 us ( 0.84%) 8 10.83 us 7.55 us 7.51 us (-0.48%) 16 11.21 us 7.46 us 7.51 us ( 0.71%) 32 10.65 us 7.53 us 7.58 us ( 0.61%) 64 10.95 us 7.74 us 7.80 us ( 0.76%) 128 11.14 us 7.83 us 7.87 us ( 0.47%) 256 10.97 us 7.94 us 7.92 us (-0.28%) 512 11.23 us 7.94 us 8.20 us ( 3.25%) 1024 11.60 us 8.12 us 8.20 us ( 0.96%) 2048 14.04 us 8.30 us 8.51 us ( 2.49%) 4096 16.88 us 9.13 us 9.07 us (-0.64%) 8192 22.50 us 10.56 us 11.22 us ( 6.26%) 16384 28.99 us 12.88 us 13.83 us ( 7.37%) 32768 40.13 us 16.76 us 16.95 us ( 1.16%) 65536 68.70 us 24.68 us 24.85 us ( 0.68%) [bandwidth] msgsize tcp smcr smcr-use-virt-buf 1 1.65 MB/s 1.59 MB/s 1.53 MB/s (-3.88%) 2 3.32 MB/s 3.17 MB/s 3.08 MB/s (-2.67%) 4 6.66 MB/s 6.33 MB/s 6.09 MB/s (-3.85%) 8 13.67 MB/s 13.45 MB/s 11.97 MB/s (-10.99%) 16 25.36 MB/s 27.15 MB/s 24.16 MB/s (-11.01%) 32 48.22 MB/s 54.24 MB/s 49.41 MB/s (-8.89%) 64 106.79 MB/s 107.32 MB/s 99.05 MB/s (-7.71%) 128 210.21 MB/s 202.46 MB/s 201.02 MB/s (-0.71%) 256 400.81 MB/s 416.81 MB/s 393.52 MB/s (-5.59%) 512 746.49 MB/s 834.12 MB/s 809.99 MB/s (-2.89%) 1024 1292.33 MB/s 1641.96 MB/s 1571.82 MB/s (-4.27%) 2048 2007.64 MB/s 2760.44 MB/s 2717.68 MB/s (-1.55%) 4096 2665.17 MB/s 4157.44 MB/s 4070.76 MB/s (-2.09%) 8192 3159.72 MB/s 4361.57 MB/s 4270.65 MB/s (-2.08%) 16384 4186.70 MB/s 4574.13 MB/s 4501.17 MB/s (-1.60%) 32768 4093.21 MB/s 4487.42 MB/s 4322.43 MB/s (-3.68%) 65536 4057.14 MB/s 4735.61 MB/s 4555.17 MB/s (-3.81%) 2) regression in buffer initialization and destruction path, which is brought by additional MR operations of sndbufs. But thanks to link group buffer reuse mechanism, the impact of this kind of regression decreases as times of buffer reuse increases. Taking 256KB sndbuf and RMB as an example, latency of some key SMC-R buffer-related function obtained by bpftrace are as follows: Function Phys-bufs Virt-bufs smcr_new_buf_create() 67154 ns 79164 ns smc_ib_buf_map_sg() 525 ns 928 ns smc_ib_get_memory_region() 162294 ns 161191 ns smc_wr_reg_send() 9957 ns 9635 ns smc_ib_put_memory_region() 203548 ns 198374 ns smc_ib_buf_unmap_sg() 508 ns 1158 ns ------------ Test environment notes: 1. Above tests run on 2 VMs within the same Host. 2. The NIC is ConnectX-4Lx, using SRIOV and passing through 2 VFs to the each VM respectively. 3. VMs' vCPUs are binded to different physical CPUs, and the binded physical CPUs are isolated by `isolcpus=xxx` cmdline. 4. NICs' queue number are set to 1. Signed-off-by: Wen Gu <guwen@linux.alibaba.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-07-18net/smc: remove redundant dma sync opsGuangguan Wang1-2/+0
smc_ib_sync_sg_for_cpu/device are the ops used for dma memory cache consistency. Smc sndbufs are dma buffers, where CPU writes data to it and PCIE device reads data from it. So for sndbufs, smc_ib_sync_sg_for_device is needed and smc_ib_sync_sg_for_cpu is redundant as PCIE device will not write the buffers. Smc rmbs are dma buffers, where PCIE device write data to it and CPU read data from it. So for rmbs, smc_ib_sync_sg_for_cpu is needed and smc_ib_sync_sg_for_device is redundant as CPU will not write the buffers. Signed-off-by: Guangguan Wang <guangguan.wang@linux.alibaba.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-05-25net/smc: set ini->smcrv2.ib_dev_v2 to NULL if SMC-Rv2 is unavailableliuyacan1-0/+1
In the process of checking whether RDMAv2 is available, the current implementation first sets ini->smcrv2.ib_dev_v2, and then allocates smc buf desc and register rmb, but the latter may fail. In this case, the pointer should be reset. Fixes: e49300a6bf62 ("net/smc: add listen processing for SMC-Rv2") Signed-off-by: liuyacan <liuyacan@corp.netease.com> Reviewed-by: Karsten Graul <kgraul@linux.ibm.com> Link: https://lore.kernel.org/r/20220525085408.812273-1-liuyacan@corp.netease.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-05-24Revert "net/smc: fix listen processing for SMC-Rv2"liuyacan1-27/+17
This reverts commit 8c3b8dc5cc9bf6d273ebe18b16e2d6882bcfb36d. Some rollback issue will be fixed in other patches in the future. Link: https://lore.kernel.org/all/20220523055056.2078994-1-liuyacan@corp.netease.com/ Fixes: 8c3b8dc5cc9b ("net/smc: fix listen processing for SMC-Rv2") Signed-off-by: liuyacan <liuyacan@corp.netease.com> Link: https://lore.kernel.org/r/20220524090230.2140302-1-liuyacan@corp.netease.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-05-23Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski1-18/+28
drivers/net/ethernet/cadence/macb_main.c 5cebb40bc955 ("net: macb: Fix PTP one step sync support") 138badbc21a0 ("net: macb: use NAPI for TX completion path") https://lore.kernel.org/all/20220523111021.31489367@canb.auug.org.au/ net/smc/af_smc.c 75c1edf23b95 ("net/smc: postpone sk_refcnt increment in connect()") 3aba103006bc ("net/smc: align the connect behaviour with TCP") https://lore.kernel.org/all/20220524114408.4bf1af38@canb.auug.org.au/ Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-05-23net/smc: fix listen processing for SMC-Rv2liuyacan1-17/+27
In the process of checking whether RDMAv2 is available, the current implementation first sets ini->smcrv2.ib_dev_v2, and then allocates smc buf desc, but the latter may fail. Unfortunately, the caller will only check the former. In this case, a NULL pointer reference will occur in smc_clc_send_confirm_accept() when accessing conn->rmb_desc. This patch does two things: 1. Use the return code to determine whether V2 is available. 2. If the return code is NODEV, continue to check whether V1 is available. Fixes: e49300a6bf62 ("net/smc: add listen processing for SMC-Rv2") Signed-off-by: liuyacan <liuyacan@corp.netease.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-05-23net/smc: postpone sk_refcnt increment in connect()liuyacan1-1/+1
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 <liuyacan@corp.netease.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-05-16net/smc: align the connect behaviour with TCPGuangguan Wang1-4/+46
Connect with O_NONBLOCK will not be completed immediately and returns -EINPROGRESS. It is possible to use selector/poll for completion by selecting the socket for writing. After select indicates writability, a second connect function call will return 0 to indicate connected successfully as TCP does, but smc returns -EISCONN. Use socket state for smc to indicate connect state, which can help smc aligning the connect behaviour with TCP. Signed-off-by: Guangguan Wang <guangguan.wang@linux.alibaba.com> Acked-by: Karsten Graul <kgraul@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-04-25net/smc: Fix slab-out-of-bounds issue in fallbackWen Gu1-23/+57
syzbot reported a slab-out-of-bounds/use-after-free issue, which was caused by accessing an already freed smc sock in fallback-specific callback functions of clcsock. This patch fixes the issue by restoring fallback-specific callback functions to original ones and resetting clcsock sk_user_data to NULL before freeing smc sock. Meanwhile, this patch introduces sk_callback_lock to make the access and assignment to sk_user_data mutually exclusive. Reported-by: syzbot+b425899ed22c6943e00b@syzkaller.appspotmail.com Fixes: 341adeec9ada ("net/smc: Forward wakeup to smc socket waitqueue after fallback") Link: https://lore.kernel.org/r/00000000000013ca8105d7ae3ada@google.com/ Signed-off-by: Wen Gu <guwen@linux.alibaba.com> Acked-by: Karsten Graul <kgraul@linux.ibm.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-04-25net/smc: Only save the original clcsock callback functionsWen Gu1-19/+36
Both listen and fallback process will save the current clcsock callback functions and establish new ones. But if both of them happen, the saved callback functions will be overwritten. So this patch introduces some helpers to ensure that only save the original callback functions of clcsock. Fixes: 341adeec9ada ("net/smc: Forward wakeup to smc socket waitqueue after fallback") Signed-off-by: Wen Gu <guwen@linux.alibaba.com> Acked-by: Karsten Graul <kgraul@linux.ibm.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-04-25net/smc: sync err code when tcp connection was refusedliuyacan1-0/+2
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 <liuyacan@corp.netease.com> Reviewed-by: Tony Lu <tonylu@linux.alibaba.com> Acked-by: Karsten Graul <kgraul@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-04-15net/smc: Fix sock leak when release after smc_shutdown()Tony Lu1-1/+3
Since commit e5d5aadcf3cd ("net/smc: fix sk_refcnt underflow on linkdown and fallback"), for a fallback connection, __smc_release() does not call sock_put() if its state is already SMC_CLOSED. When calling smc_shutdown() after falling back, its state is set to SMC_CLOSED but does not call sock_put(), so this patch calls it. Reported-and-tested-by: syzbot+6e29a053eb165bd50de5@syzkaller.appspotmail.com Fixes: e5d5aadcf3cd ("net/smc: fix sk_refcnt underflow on linkdown and fallback") Signed-off-by: Tony Lu <tonylu@linux.alibaba.com> Acked-by: Karsten Graul <kgraul@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-04-11net/smc: Fix af_ops of child socket pointing to released memoryKarsten Graul1-2/+12
Child sockets may inherit the af_ops from the parent listen socket. When the listen socket is released then the af_ops of the child socket points to released memory. Solve that by restoring the original af_ops for child sockets which inherited the parent af_ops. And clear any inherited user_data of the parent socket. Fixes: 8270d9c21041 ("net/smc: Limit backlog connections") Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com> Signed-off-by: Karsten Graul <kgraul@linux.ibm.com> Reviewed-by: D. Wythe <alibuda@linux.alibaba.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-03-07net/smc: fix compile warning for smc_sysctlDust Li1-9/+6
kernel test robot reports multiple warning for smc_sysctl: In file included from net/smc/smc_sysctl.c:17: >> net/smc/smc_sysctl.h:23:5: warning: no previous prototype \ for function 'smc_sysctl_init' [-Wmissing-prototypes] int smc_sysctl_init(void) ^ and >> WARNING: modpost: vmlinux.o(.text+0x12ced2d): Section mismatch \ in reference from the function smc_sysctl_exit() to the variable .init.data:smc_sysctl_ops The function smc_sysctl_exit() references the variable __initdata smc_sysctl_ops. This is often because smc_sysctl_exit lacks a __initdata annotation or the annotation of smc_sysctl_ops is wrong. and net/smc/smc_sysctl.c: In function 'smc_sysctl_init_net': net/smc/smc_sysctl.c:47:17: error: 'struct netns_smc' has no member named 'smc_hdr' 47 | net->smc.smc_hdr = register_net_sysctl(net, "net/smc", table); Since we don't need global sysctl initialization. To make things clean and simple, remove the global pernet_operations and smc_sysctl_{init|exit}. Call smc_sysctl_net_{init|exit} directly from smc_net_{init|exit}. Also initialized sysctl_autocorking_size if CONFIG_SYSCTL it not set, this make sure SMC autocorking is enabled by default if CONFIG_SYSCTL is not set. Fixes: 462791bbfa35 ("net/smc: add sysctl interface for SMC") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Dust Li <dust.li@linux.alibaba.com> Tested-by: Randy Dunlap <rdunlap@infradead.org> # build-tested Signed-off-by: David S. Miller <davem@davemloft.net>
2022-03-03Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski1-3/+11
net/batman-adv/hard-interface.c commit 690bb6fb64f5 ("batman-adv: Request iflink once in batadv-on-batadv check") commit 6ee3c393eeb7 ("batman-adv: Demote batadv-on-batadv skip error message") https://lore.kernel.org/all/20220302163049.101957-1-sw@simonwunderlich.de/ net/smc/af_smc.c commit 4d08b7b57ece ("net/smc: Fix cleanup when register ULP fails") commit 462791bbfa35 ("net/smc: add sysctl interface for SMC") https://lore.kernel.org/all/20220302112209.355def40@canb.auug.org.au/ Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-03-01net/smc: don't send in the BH context if sock_owned_by_userDust Li1-0/+16
Send data all the way down to the RDMA device is a time consuming operation(get a new slot, maybe do RDMA Write and send a CDC, etc). Moving those operations from BH to user context is good for performance. If the sock_lock is hold by user, we don't try to send data out in the BH context, but just mark we should send. Since the user will release the sock_lock soon, we can do the sending there. Add smc_release_cb() which will be called in release_sock() and try send in the callback if needed. This patch moves the sending part out from BH if sock lock is hold by user. In my testing environment, this saves about 20% softirq in the qperf 4K tcp_bw test in the sender side with no noticeable throughput drop. Signed-off-by: Dust Li <dust.li@linux.alibaba.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-03-01net/smc: send directly on setting TCP_NODELAYDust Li1-2/+2
In commit ea785a1a573b("net/smc: Send directly when TCP_CORK is cleared"), we don't use delayed work to implement cork. This patch use the same algorithm, removes the delayed work when setting TCP_NODELAY and send directly in setsockopt(). This also makes the TCP_NODELAY the same as TCP. Cc: Tony Lu <tonylu@linux.alibaba.com> Signed-off-by: Dust Li <dust.li@linux.alibaba.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-03-01net/smc: add sysctl interface for SMCDust Li1-0/+10
This patch add sysctl interface to support container environment for SMC as we talk in the mail list. Link: https://lore.kernel.org/netdev/20220224020253.GF5443@linux.alibaba.com Co-developed-by: Tony Lu <tonylu@linux.alibaba.com> Signed-off-by: Tony Lu <tonylu@linux.alibaba.com> Signed-off-by: Dust Li <dust.li@linux.alibaba.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-28net/smc: Fix cleanup when register ULP failsTony Lu1-1/+3
This patch calls smc_ib_unregister_client() when tcp_register_ulp() fails, and make sure to clean it up. Fixes: d7cd421da9da ("net/smc: Introduce TCP ULP support") Signed-off-by: Tony Lu <tonylu@linux.alibaba.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-25net/smc: fix connection leakD. Wythe1-2/+8
There's a potential leak issue under following execution sequence : smc_release smc_connect_work if (sk->sk_state == SMC_INIT) send_clc_confirim tcp_abort(); ... sk.sk_state = SMC_ACTIVE smc_close_active switch(sk->sk_state) { ... case SMC_ACTIVE: smc_close_final() // then wait peer closed Unfortunately, tcp_abort() may discard CLC CONFIRM messages that are still in the tcp send buffer, in which case our connection token cannot be delivered to the server side, which means that we cannot get a passive close message at all. Therefore, it is impossible for the to be disconnected at all. This patch tries a very simple way to avoid this issue, once the state has changed to SMC_ACTIVE after tcp_abort(), we can actively abort the smc connection, considering that the state is SMC_INIT before tcp_abort(), abandoning the complete disconnection process should not cause too much problem. In fact, this problem may exist as long as the CLC CONFIRM message is not received by the server. Whether a timer should be added after smc_close_final() needs to be discussed in the future. But even so, this patch provides a faster release for connection in above case, it should also be valuable. Fixes: 39f41f367b08 ("net/smc: common release code for non-accepted sockets") Signed-off-by: D. Wythe <alibuda@linux.alibaba.com> Acked-by: Karsten Graul <kgraul@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-19net/smc: unlock on error paths in __smc_setsockopt()Dan Carpenter1-4/+8
These two error paths need to release_sock(sk) before returning. Fixes: a6a6fe27bab4 ("net/smc: Dynamic control handshake limitation by socket options") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Reviewed-by: D. Wythe <alibuda@linux.alibaba.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-17Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski1-3/+7
No conflicts. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-16net/smc: return ETIMEDOUT when smc_connect_clc() timeoutD. Wythe1-1/+7
When smc_connect_clc() times out, it will return -EAGAIN(tcp_recvmsg retuns -EAGAIN while timeout), then this value will passed to the application, which is quite confusing to the applications, makes inconsistency with TCP. From the manual of connect, ETIMEDOUT is more suitable, and this patch try convert EAGAIN to ETIMEDOUT in that case. Signed-off-by: D. Wythe <alibuda@linux.alibaba.com> Reviewed-by: Karsten Graul <kgraul@linux.ibm.com> Link: https://lore.kernel.org/r/1644913490-21594-1-git-send-email-alibuda@linux.alibaba.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-11net/smc: Add global configure for handshake limitation by netlinkD. Wythe1-0/+42
Although we can control SMC handshake limitation through socket options, which means that applications who need it must modify their code. It's quite troublesome for many existing applications. This patch modifies the global default value of SMC handshake limitation through netlink, providing a way to put constraint on handshake without modifies any code for applications. Suggested-by: Tony Lu <tonylu@linux.alibaba.com> Signed-off-by: D. Wythe <alibuda@linux.alibaba.com> Reviewed-by: Tony Lu <tonylu@linux.alibaba.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-11net/smc: Dynamic control handshake limitation by socket optionsD. Wythe1-1/+68
This patch aims to add dynamic control for SMC handshake limitation for every smc sockets, in production environment, it is possible for the same applications to handle different service types, and may have different opinion on SMC handshake limitation. This patch try socket options to complete it, since we don't have socket option level for SMC yet, which requires us to implement it at the same time. This patch does the following: - add new socket option level: SOL_SMC. - add new SMC socket option: SMC_LIMIT_HS. - provide getter/setter for SMC socket options. Link: https://lore.kernel.org/all/20f504f961e1a803f85d64229ad84260434203bd.1644323503.git.alibuda@linux.alibaba.com/ Signed-off-by: D. Wythe <alibuda@linux.alibaba.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-11net/smc: Limit SMC visits when handshake workqueue congestedD. Wythe1-0/+17
This patch intends to provide a mechanism to put constraint on SMC connections visit according to the pressure of SMC handshake process. At present, frequent visits will cause the incoming connections to be backlogged in SMC handshake queue, raise the connections established time. Which is quite unacceptable for those applications who base on short lived connections. There are two ways to implement this mechanism: 1. Put limitation after TCP established. 2. Put limitation before TCP established. In the first way, we need to wait and receive CLC messages that the client will potentially send, and then actively reply with a decline message, in a sense, which is also a sort of SMC handshake, affect the connections established time on its way. In the second way, the only problem is that we need to inject SMC logic into TCP when it is about to reply the incoming SYN, since we already do that, it's seems not a problem anymore. And advantage is obvious, few additional processes are required to complete the constraint. This patch use the second way. After this patch, connections who beyond constraint will not informed any SMC indication, and SMC will not be involved in any of its subsequent processes. Link: https://lore.kernel.org/all/1641301961-59331-1-git-send-email-alibuda@linux.alibaba.com/ Signed-off-by: D. Wythe <alibuda@linux.alibaba.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-11net/smc: Limit backlog connectionsD. Wythe1-0/+45
Current implementation does not handling backlog semantics, one potential risk is that server will be flooded by infinite amount connections, even if client was SMC-incapable. This patch works to put a limit on backlog connections, referring to the TCP implementation, we divides SMC connections into two categories: 1. Half SMC connection, which includes all TCP established while SMC not connections. 2. Full SMC connection, which includes all SMC established connections. For half SMC connection, since all half SMC connections starts with TCP established, we can achieve our goal by put a limit before TCP established. Refer to the implementation of TCP, this limits will based on not only the half SMC connections but also the full connections, which is also a constraint on full SMC connections. For full SMC connections, although we know exactly where it starts, it's quite hard to put a limit before it. The easiest way is to block wait before receive SMC confirm CLC message, while it's under protection by smc_server_lgr_pending, a global lock, which leads this limit to the entire host instead of a single listen socket. Another way is to drop the full connections, but considering the cast of SMC connections, we prefer to keep full SMC connections. Even so, the limits of full SMC connections still exists, see commits about half SMC connection below. After this patch, the limits of backend connection shows like: For SMC: 1. Client with SMC-capability can makes 2 * backlog full SMC connections or 1 * backlog half SMC connections and 1 * backlog full SMC connections at most. 2. Client without SMC-capability can only makes 1 * backlog half TCP connections and 1 * backlog full TCP connections. Signed-off-by: D. Wythe <alibuda@linux.alibaba.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-11net/smc: Make smc_tcp_listen_work() independentD. Wythe1-2/+11
In multithread and 10K connections benchmark, the backend TCP connection established very slowly, and lots of TCP connections stay in SYN_SENT state. Client: smc_run wrk -c 10000 -t 4 http://server the netstate of server host shows like: 145042 times the listen queue of a socket overflowed 145042 SYNs to LISTEN sockets dropped One reason of this issue is that, since the smc_tcp_listen_work() shared the same workqueue (smc_hs_wq) with smc_listen_work(), while the smc_listen_work() do blocking wait for smc connection established. Once the workqueue became congested, it's will block the accept() from TCP listen. This patch creates a independent workqueue(smc_tcp_ls_wq) for smc_tcp_listen_work(), separate it from smc_listen_work(), which is quite acceptable considering that smc_tcp_listen_work() runs very fast. Signed-off-by: D. Wythe <alibuda@linux.alibaba.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-11net/smc: Avoid overwriting the copies of clcsock callback functionsWen Gu1-3/+7
The callback functions of clcsock will be saved and replaced during the fallback. But if the fallback happens more than once, then the copies of these callback functions will be overwritten incorrectly, resulting in a loop call issue: clcsk->sk_error_report |- smc_fback_error_report() <------------------------------| |- smc_fback_forward_wakeup() | (loop) |- clcsock_callback() (incorrectly overwritten) | |- smc->clcsk_error_report() ------------------| So this patch fixes the issue by saving these function pointers only once in the fallback and avoiding overwriting. Reported-by: syzbot+4de3c0e8a263e1e499bc@syzkaller.appspotmail.com Fixes: 341adeec9ada ("net/smc: Forward wakeup to smc socket waitqueue after fallback") Link: https://lore.kernel.org/r/0000000000006d045e05d78776f6@google.com Signed-off-by: Wen Gu <guwen@linux.alibaba.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-03Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski1-15/+118
No conflicts. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-01-31net/smc: Cork when sendpage with MSG_SENDPAGE_NOTLAST flagTony Lu1-1/+3
This introduces a new corked flag, MSG_SENDPAGE_NOTLAST, which is involved in syscall sendfile() [1], it indicates this is not the last page. So we can cork the data until the page is not specify this flag. It has the same effect as MSG_MORE, but existed in sendfile() only. This patch adds a option MSG_SENDPAGE_NOTLAST for corking data, try to cork more data before sending when using sendfile(), which acts like TCP's behaviour. Also, this reimplements the default sendpage to inform that it is supported to some extent. [1] https://man7.org/linux/man-pages/man2/sendfile.2.html Signed-off-by: Tony Lu <tonylu@linux.alibaba.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-01-31net/smc: Send directly when TCP_CORK is clearedTony Lu1-2/+2
According to the man page of TCP_CORK [1], if set, don't send out partial frames. All queued partial frames are sent when option is cleared again. When applications call setsockopt to disable TCP_CORK, this call is protected by lock_sock(), and tries to mod_delayed_work() to 0, in order to send pending data right now. However, the delayed work smc_tx_work is also protected by lock_sock(). There introduces lock contention for sending data. To fix it, send pending data directly which acts like TCP, without lock_sock() protected in the context of setsockopt (already lock_sock()ed), and cancel unnecessary dealyed work, which is protected by lock. [1] https://linux.die.net/man/7/tcp Signed-off-by: Tony Lu <tonylu@linux.alibaba.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-01-31net/smc: Forward wakeup to smc socket waitqueue after fallbackWen Gu1-15/+118
When we replace TCP with SMC and a fallback occurs, there may be some socket waitqueue entries remaining in smc socket->wq, such as eppoll_entries inserted by userspace applications. After the fallback, data flows over TCP/IP and only clcsocket->wq will be woken up. Applications can't be notified by the entries which were inserted in smc socket->wq before fallback. So we need a mechanism to wake up smc socket->wq at the same time if some entries remaining in it. The current workaround is to transfer the entries from smc socket->wq to clcsock->wq during the fallback. But this may cause a crash like this: general protection fault, probably for non-canonical address 0xdead000000000100: 0000 [#1] PREEMPT SMP PTI CPU: 3 PID: 0 Comm: swapper/3 Kdump: loaded Tainted: G E 5.16.0+ #107 RIP: 0010:__wake_up_common+0x65/0x170 Call Trace: <IRQ> __wake_up_common_lock+0x7a/0xc0 sock_def_readable+0x3c/0x70 tcp_data_queue+0x4a7/0xc40 tcp_rcv_established+0x32f/0x660 ? sk_filter_trim_cap+0xcb/0x2e0 tcp_v4_do_rcv+0x10b/0x260 tcp_v4_rcv+0xd2a/0xde0 ip_protocol_deliver_rcu+0x3b/0x1d0 ip_local_deliver_finish+0x54/0x60 ip_local_deliver+0x6a/0x110 ? tcp_v4_early_demux+0xa2/0x140 ? tcp_v4_early_demux+0x10d/0x140 ip_sublist_rcv_finish+0x49/0x60 ip_sublist_rcv+0x19d/0x230 ip_list_rcv+0x13e/0x170 __netif_receive_skb_list_core+0x1c2/0x240 netif_receive_skb_list_internal+0x1e6/0x320 napi_complete_done+0x11d/0x190 mlx5e_napi_poll+0x163/0x6b0 [mlx5_core] __napi_poll+0x3c/0x1b0 net_rx_action+0x27c/0x300 __do_softirq+0x114/0x2d2 irq_exit_rcu+0xb4/0xe0 common_interrupt+0xba/0xe0 </IRQ> <TASK> The crash is caused by privately transferring waitqueue entries from smc socket->wq to clcsock->wq. The owners of these entries, such as epoll, have no idea that the entries have been transferred to a different socket wait queue and still use original waitqueue spinlock (smc socket->wq.wait.lock) to make the entries operation exclusive, but it doesn't work. The operations to the entries, such as removing from the waitqueue (now is clcsock->wq after fallback), may cause a crash when clcsock waitqueue is being iterated over at the moment. This patch tries to fix this by no longer transferring wait queue entries privately, but introducing own implementations of clcsock's callback functions in fallback situation. The callback functions will forward the wakeup to smc socket->wq if clcsock->wq is actually woken up and smc socket->wq has remaining entries. Fixes: 2153bd1e3d3d ("net/smc: Transfer remaining wait queue entries during fallback") Suggested-by: Karsten Graul <kgraul@linux.ibm.com> Signed-off-by: Wen Gu <guwen@linux.alibaba.com> Acked-by: Karsten Graul <kgraul@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-01-24net/smc: Transitional solution for clcsock race issueWen Gu1-12/+51
We encountered a crash in smc_setsockopt() and it is caused by accessing smc->clcsock after clcsock was released. BUG: kernel NULL pointer dereference, address: 0000000000000020 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 1 PID: 50309 Comm: nginx Kdump: loaded Tainted: G E 5.16.0-rc4+ #53 RIP: 0010:smc_setsockopt+0x59/0x280 [smc] Call Trace: <TASK> __sys_setsockopt+0xfc/0x190 __x64_sys_setsockopt+0x20/0x30 do_syscall_64+0x34/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f16ba83918e </TASK> This patch tries to fix it by holding clcsock_release_lock and checking whether clcsock has already been released before access. In case that a crash of the same reason happens in smc_getsockopt() or smc_switch_to_fallback(), this patch also checkes smc->clcsock in them too. And the caller of smc_switch_to_fallback() will identify whether fallback succeeds according to the return value. Fixes: fd57770dd198 ("net/smc: wait for pending work before clcsock release_sock") Link: https://lore.kernel.org/lkml/5dd7ffd1-28e2-24cc-9442-1defec27375e@linux.ibm.com/T/ Signed-off-by: Wen Gu <guwen@linux.alibaba.com> Acked-by: Karsten Graul <kgraul@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-01-13net/smc: Introduce a new conn->lgr validity check helperWen Gu1-1/+5
It is no longer suitable to identify whether a smc connection is registered in a link group through checking if conn->lgr is NULL, because conn->lgr won't be reset even the connection is unregistered from a link group. So this patch introduces a new helper smc_conn_lgr_valid() and replaces all the check of conn->lgr in original implementation with the new helper to judge if conn->lgr is valid to use. Signed-off-by: Wen Gu <guwen@linux.alibaba.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-01-09Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski1-3/+5
Merge in fixes directly in prep for the 5.17 merge window. No conflicts. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-01-06net/smc: Reset conn->lgr when link group registration failsWen Gu1-3/+5
SMC connections might fail to be registered in a link group due to unable to find a usable link during its creation. As a result, smc_conn_create() will return a failure and most resources related to the connection won't be applied or initialized, such as conn->abort_work or conn->lnk. If smc_conn_free() is invoked later, it will try to access the uninitialized resources related to the connection, thus causing a warning or crash. This patch tries to fix this by resetting conn->lgr to NULL if an abnormal exit occurs in smc_lgr_register_conn(), thus avoiding the access to uninitialized resources in smc_conn_free(). Meanwhile, the new created link group should be terminated if smc connections can't be registered in it. So smc_lgr_cleanup_early() is modified to take care of link group only and invoked to terminate unusable link group by smc_conn_create(). The call to smc_conn_free() is moved out from smc_lgr_cleanup_early() to smc_conn_abort(). Fixes: 56bc3b2094b4 ("net/smc: assign link to a new connection") Suggested-by: Karsten Graul <kgraul@linux.ibm.com> Signed-off-by: Wen Gu <guwen@linux.alibaba.com> Acked-by: Karsten Graul <kgraul@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-01-02net/smc: Introduce TCP ULP supportTony Lu1-7/+86
This implements TCP ULP for SMC, helps applications to replace TCP with SMC protocol in place. And we use it to implement transparent replacement. This replaces original TCP sockets with SMC, reuse TCP as clcsock when calling setsockopt with TCP_ULP option, and without any overhead. To replace TCP sockets with SMC, there are two approaches: - use setsockopt() syscall with TCP_ULP option, if error, it would fallback to TCP. - use BPF prog with types BPF_CGROUP_INET_SOCK_CREATE or others to replace transparently. BPF hooks some points in create socket, bind and others, users can inject their BPF logics without modifying their applications, and choose which connections should be replaced with SMC by calling setsockopt() in BPF prog, based on rules, such as TCP tuples, PID, cgroup, etc... BPF doesn't support calling setsockopt with TCP_ULP now, I will send the patches after this accepted. Signed-off-by: Tony Lu <tonylu@linux.alibaba.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-12-16Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski1-1/+3
No conflicts. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-12-16net/smc: Prevent smc_release() from long blockingD. Wythe1-1/+3
In nginx/wrk benchmark, there's a hung problem with high probability on case likes that: (client will last several minutes to exit) server: smc_run nginx client: smc_run wrk -c 10000 -t 1 http://server Client hangs with the following backtrace: 0 [ffffa7ce8Of3bbf8] __schedule at ffffffff9f9eOd5f 1 [ffffa7ce8Of3bc88] schedule at ffffffff9f9eløe6 2 [ffffa7ce8Of3bcaO] schedule_timeout at ffffffff9f9e3f3c 3 [ffffa7ce8Of3bd2O] wait_for_common at ffffffff9f9el9de 4 [ffffa7ce8Of3bd8O] __flush_work at ffffffff9fOfeOl3 5 [ffffa7ce8øf3bdfO] smc_release at ffffffffcO697d24 [smc] 6 [ffffa7ce8Of3be2O] __sock_release at ffffffff9f8O2e2d 7 [ffffa7ce8Of3be4ø] sock_close at ffffffff9f8ø2ebl 8 [ffffa7ce8øf3be48] __fput at ffffffff9f334f93 9 [ffffa7ce8Of3be78] task_work_run at ffffffff9flOlff5 10 [ffffa7ce8Of3beaO] do_exit at ffffffff9fOe5Ol2 11 [ffffa7ce8Of3bflO] do_group_exit at ffffffff9fOe592a 12 [ffffa7ce8Of3bf38] __x64_sys_exit_group at ffffffff9fOe5994 13 [ffffa7ce8Of3bf4O] do_syscall_64 at ffffffff9f9d4373 14 [ffffa7ce8Of3bfsO] entry_SYSCALL_64_after_hwframe at ffffffff9fa0007c This issue dues to flush_work(), which is used to wait for smc_connect_work() to finish in smc_release(). Once lots of smc_connect_work() was pending or all executing work dangling, smc_release() has to block until one worker comes to free, which is equivalent to wait another smc_connnect_work() to finish. In order to fix this, There are two changes: 1. For those idle smc_connect_work(), cancel it from the workqueue; for executing smc_connect_work(), waiting for it to finish. For that purpose, replace flush_work() with cancel_work_sync(). 2. Since smc_connect() hold a reference for passive closing, if smc_connect_work() has been cancelled, release the reference. Fixes: 24ac3a08e658 ("net/smc: rebuild nonblocking connect") Reported-by: Tony Lu <tonylu@linux.alibaba.com> Tested-by: Dust Li <dust.li@linux.alibaba.com> Reviewed-by: Dust Li <dust.li@linux.alibaba.com> Reviewed-by: Tony Lu <tonylu@linux.alibaba.com> Signed-off-by: D. Wythe <alibuda@linux.alibaba.com> Acked-by: Karsten Graul <kgraul@linux.ibm.com> Link: https://lore.kernel.org/r/1639571361-101128-1-git-send-email-alibuda@linux.alibaba.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-11-26Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski1-3/+11
drivers/net/ipa/ipa_main.c 8afc7e471ad3 ("net: ipa: separate disabling setup from modem stop") 76b5fbcd6b47 ("net: ipa: kill ipa_modem_init()") Duplicated include, drop one. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-11-26net/smc: Don't call clcsock shutdown twice when smc shutdownTony Lu1-1/+7
When applications call shutdown() with SHUT_RDWR in userspace, smc_close_active() calls kernel_sock_shutdown(), and it is called twice in smc_shutdown(). This fixes this by checking sk_state before do clcsock shutdown, and avoids missing the application's call of smc_shutdown(). Link: https://lore.kernel.org/linux-s390/1f67548e-cbf6-0dce-82b5-10288a4583bd@linux.ibm.com/ Fixes: 606a63c9783a ("net/smc: Ensure the active closing peer first closes clcsock") Signed-off-by: Tony Lu <tonylu@linux.alibaba.com> Reviewed-by: Wen Gu <guwen@linux.alibaba.com> Acked-by: Karsten Graul <kgraul@linux.ibm.com> Link: https://lore.kernel.org/r/20211126024134.45693-1-tonylu@linux.alibaba.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-11-24net/smc: Fix loop in smc_listenGuo DaXing1-1/+3
The kernel_listen function in smc_listen will fail when all the available ports are occupied. At this point smc->clcsock->sk->sk_data_ready has been changed to smc_clcsock_data_ready. When we call smc_listen again, now both smc->clcsock->sk->sk_data_ready and smc->clcsk_data_ready point to the smc_clcsock_data_ready function. The smc_clcsock_data_ready() function calls lsmc->clcsk_data_ready which now points to itself resulting in an infinite loop. This patch restores smc->clcsock->sk->sk_data_ready with the old value. Fixes: a60a2b1e0af1 ("net/smc: reduce active tcp_listen workers") Signed-off-by: Guo DaXing <guodaxing@huawei.com> Acked-by: Tony Lu <tonylu@linux.alibaba.com> Signed-off-by: Karsten Graul <kgraul@linux.ibm.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-11-22net/smc: Avoid warning of possible recursive lockingWen Gu1-1/+1
Possible recursive locking is detected by lockdep when SMC falls back to TCP. The corresponding warnings are as follows: ============================================ WARNING: possible recursive locking detected 5.16.0-rc1+ #18 Tainted: G E -------------------------------------------- wrk/1391 is trying to acquire lock: ffff975246c8e7d8 (&ei->socket.wq.wait){..-.}-{3:3}, at: smc_switch_to_fallback+0x109/0x250 [smc] but task is already holding lock: ffff975246c8f918 (&ei->socket.wq.wait){..-.}-{3:3}, at: smc_switch_to_fallback+0xfe/0x250 [smc] other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&ei->socket.wq.wait); lock(&ei->socket.wq.wait); *** DEADLOCK *** May be due to missing lock nesting notation 2 locks held by wrk/1391: #0: ffff975246040130 (sk_lock-AF_SMC){+.+.}-{0:0}, at: smc_connect+0x43/0x150 [smc] #1: ffff975246c8f918 (&ei->socket.wq.wait){..-.}-{3:3}, at: smc_switch_to_fallback+0xfe/0x250 [smc] stack backtrace: Call Trace: <TASK> dump_stack_lvl+0x56/0x7b __lock_acquire+0x951/0x11f0 lock_acquire+0x27a/0x320 ? smc_switch_to_fallback+0x109/0x250 [smc] ? smc_switch_to_fallback+0xfe/0x250 [smc] _raw_spin_lock_irq+0x3b/0x80 ? smc_switch_to_fallback+0x109/0x250 [smc] smc_switch_to_fallback+0x109/0x250 [smc] smc_connect_fallback+0xe/0x30 [smc] __smc_connect+0xcf/0x1090 [smc] ? mark_held_locks+0x61/0x80 ? __local_bh_enable_ip+0x77/0xe0 ? lockdep_hardirqs_on+0xbf/0x130 ? smc_connect+0x12a/0x150 [smc] smc_connect+0x12a/0x150 [smc] __sys_connect+0x8a/0xc0 ? syscall_enter_from_user_mode+0x20/0x70 __x64_sys_connect+0x16/0x20 do_syscall_64+0x34/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae The nested locking in smc_switch_to_fallback() is considered to possibly cause a deadlock because smc_wait->lock and clc_wait->lock are the same type of lock. But actually it is safe so far since there is no other place trying to obtain smc_wait->lock when clc_wait->lock is held. So the patch replaces spin_lock() with spin_lock_nested() to avoid false report by lockdep. Link: https://lkml.org/lkml/2021/11/19/962 Fixes: 2153bd1e3d3d ("Transfer remaining wait queue entries during fallback") Reported-by: syzbot+e979d3597f48262cb4ee@syzkaller.appspotmail.com Signed-off-by: Wen Gu <guwen@linux.alibaba.com> Acked-by: Tony Lu <tonylu@linux.alibaba.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-11-18Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski1-0/+14
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
generated by cgit v1.2.3 (git 2.39.1) at 2024-08-22 07:51:04 +0000