Greeting, FYI, we noticed the following commit (built with gcc-9): commit: 899aba891cab1555c9ca16a558769efb177baf44 ("RDMA/rxe: Fix FIXME in rxe_udp_encap_recv()") https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git master in testcase: blktests version: blktests-x86_64-a210761-1_20210124 with following parameters: test: srp-group-00 ucode: 0xe2 on test machine: 4 threads Intel(R) Core(TM) i5-6500 CPU @ 3.20GHz with 32G memory caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): If you fix the issue, kindly add following tag Reported-by: kernel test robot [ 28.924776] ------------[ cut here ]------------ [ 28.945715] ib_srpt:srpt_cm_req_recv: ib_srpt imm_data_offset = 68 [ 28.950300] WARNING: CPU: 3 PID: 29 at drivers/infiniband/sw/rxe/rxe_comp.c:761 rxe_completer+0x9bc/0xda0 [rdma_rxe] [ 28.957254] ib_srpt:srpt_create_ch_ib: ib_srpt srpt_create_ch_ib: max_cqe= 8191 max_sge= 32 sq_size = 4096 ch= 00000000f53b66aa [ 28.967012] Modules linked in: ib_srp scsi_transport_srp target_core_user uio target_core_pscsi target_core_file ib_srpt target_core_iblock target_core _mod rdma_cm iw_cm [ 28.978500] ib_srpt:srpt_cm_req_recv: ib_srpt registering src addr 192.168.3.94 or i_port_id 0xfe8000000000000066006afffe3091ac [ 28.978501] ib_cm [ 28.978509] ib_srpt:srpt_cm_req_recv: ib_srpt Establish connection sess=000000002be5fb65 name=192.168.3.94 ch=00000000f53b66aa [ 28.993644] ib_umad scsi_debug [ 29.005180] ib_srp:srp_max_it_iu_len: ib_srp: max_iu_len = 8260 [ 29.007142] rdma_rxe ip6_udp_tunnel udp_tunnel ib_uverbs ib_core null_blk loop xfs libcrc32c dm_multipath [ 29.018538] scsi host5: ib_srp: using immediate data [ 29.018685] ib_srpt:srpt_zerolength_write: ib_srpt 192.168.3.94-20: queued zerolength write [ 29.018935] ib_srpt Received SRP_LOGIN_REQ with i_port_id fe80:0000:0000:0000:6600:6aff:fe30:91ac, t_port_id 6600:6aff:fe30:91ac:6600:6aff:fe30:91ac an d it_iu_len 8260 on port 1 (guid=fe80:0000:0000:0000:6600:6aff:fe30:91ac); pkey 0xffff [ 29.018971] ib_srpt:srpt_cm_req_recv: ib_srpt imm_data_offset = 68 [ 29.019560] ib_srpt:srpt_create_ch_ib: ib_srpt srpt_create_ch_ib: max_cqe= 8191 max_sge= 32 sq_size = 4096 ch= 000000009d5609e2 [ 29.019576] ib_srpt:srpt_cm_req_recv: ib_srpt registering src addr 192.168.3.94 or i_port_id 0xfe8000000000000066006afffe3091ac [ 29.019584] ib_srpt:srpt_cm_req_recv: ib_srpt Establish connection sess=000000004137b4b8 name=192.168.3.94 ch=000000009d5609e2 [ 29.019875] ib_srp:srp_max_it_iu_len: ib_srp: max_iu_len = 8260 [ 29.019877] scsi host5: ib_srp: using immediate data [ 29.020008] ------------[ cut here ]------------ [ 29.020008] refcount_t: underflow; use-after-free. [ 29.020014] WARNING: CPU: 1 PID: 19 at lib/refcount.c:28 refcount_warn_saturate+0xa6/0x100 [ 29.020018] Modules linked in: ib_srp scsi_transport_srp target_core_user uio target_core_pscsi target_core_file ib_srpt target_core_iblock target_core _mod rdma_cm iw_cm ib_cm ib_umad scsi_debug rdma_rxe ip6_udp_tunnel udp_tunnel ib_uverbs ib_core null_blk loop xfs libcrc32c dm_multipath dm_mod ipmi_devi ntf ipmi_msghandler sd_mod t10_pi sg intel_rapl_msr intel_rapl_common x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm irqbypass crct10dif_pcl mul i915 crc32_pclmul crc32c_intel dell_wmi ghash_clmulni_intel dell_smbios intel_gtt rapl sparse_keymap wmi_bmof intel_cstate dell_wmi_descriptor drm_kms _helper ahci libahci syscopyarea mei_wdt dcdbas intel_uncore sysfillrect sysimgblt i2c_i801 fb_sys_fops libata i2c_smbus mei_me drm mei wmi intel_pch_ther mal video intel_pmc_core acpi_pad ip_tables [ 29.020055] CPU: 1 PID: 19 Comm: ksoftirqd/1 Tainted: G I 5.11.0-rc4-00158-g899aba891cab #1 [ 29.020058] Hardware name: Dell Inc. OptiPlex 7040/0Y7WYT, BIOS 1.1.1 10/07/2015 [ 29.020059] RIP: 0010:refcount_warn_saturate+0xa6/0x100 [ 29.020061] Code: 05 a0 6e 5f 01 01 e8 93 40 5d 00 0f 0b c3 80 3d 8e 6e 5f 01 00 75 95 48 c7 c7 f8 24 39 82 c6 05 7e 6e 5f 01 01 e8 74 40 5d 00 <0f> 0b c3 80 3d 6d 6e 5f 01 00 0f 85 72 ff ff ff 48 c7 c7 50 25 39 [ 29.020062] RSP: 0018:ffffc900000f7be0 EFLAGS: 00010282 [ 29.020064] RAX: 0000000000000000 RBX: ffff88886b686a28 RCX: 0000000000000027 [ 29.020065] RDX: 0000000000000027 RSI: 0000000000000002 RDI: ffff888871c97cf8 [ 29.020066] RBP: ffff88886b686a00 R08: ffff888871c97cf0 R09: ffffc900000f7b78 [ 29.020067] R10: 0000000000000001 R11: 0000000000000002 R12: ffff88886de88000 [ 29.020068] R13: 000000000000000c R14: ffff88886e2ba000 R15: ffff88886e2ba008 [ 29.020069] FS: 0000000000000000(0000) GS:ffff888871c80000(0000) knlGS:0000000000000000 [ 29.020070] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 29.020071] CR2: 00007f9e89e5d000 CR3: 0000000870c8e001 CR4: 00000000003706e0 [ 29.020072] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 29.020073] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 29.020073] Call Trace: [ 29.020076] rxe_responder+0x11c/0x2220 [rdma_rxe] [ 29.020081] ? ip_route_output_key_hash+0x76/0xa0 [ 29.020084] ? xfrm_lookup_route+0x1e/0xc0 [ 29.020087] rxe_do_task+0x9c/0xe0 [rdma_rxe] [ 29.020092] rxe_rcv+0x2dc/0x8a0 [rdma_rxe] [ 29.020095] ? copy_data+0xc1/0x2a0 [rdma_rxe] [ 29.020100] rxe_requester+0x752/0x1120 [rdma_rxe] [ 29.020103] rxe_do_task+0x9c/0xe0 [rdma_rxe] [ 29.020107] tasklet_action_common+0x58/0x100 [ 29.020111] __do_softirq+0xe6/0x2ca [ 29.020113] ? smpboot_thread_fn+0x26/0x1e0 [ 29.020115] run_ksoftirqd+0x1a/0x40 [ 29.020118] smpboot_thread_fn+0x10b/0x1e0 [ 29.020120] ? sort_range+0x20/0x20 [ 29.020121] kthread+0x116/0x160 [ 29.020124] ? kthread_park+0xa0/0xa0 [ 29.020125] ret_from_fork+0x22/0x30 [ 29.020129] ---[ end trace d22cfc8971a08f85 ]--- To reproduce: git clone https://github.com/intel/lkp-tests.git cd lkp-tests bin/lkp install job.yaml # job file is attached in this email bin/lkp split-job --compatible job.yaml bin/lkp run compatible-job.yaml Thanks, Oliver Sang