================================================================== BUG: KCSAN: data-race in tcp_assign_congestion_control / tcp_v6_syn_recv_sock read-write to 0xffff888103ccb073 of 1 bytes by interrupt on cpu 0: tcp_assign_congestion_control+0x2d3/0x310 net/ipv4/tcp_cong.c:-1 tcp_ca_openreq_child+0x196/0x1d0 net/ipv4/tcp_minisocks.c:522 tcp_v4_syn_recv_sock+0x4ce/0xa90 net/ipv4/tcp_ipv4.c:1760 tcp_v6_syn_recv_sock+0xb1/0xe70 net/ipv6/tcp_ipv6.c:1340 tcp_check_req+0xddd/0x1150 net/ipv4/tcp_minisocks.c:927 tcp_v4_rcv+0xeda/0x1d90 net/ipv4/tcp_ipv4.c:2238 ip_protocol_deliver_rcu+0x395/0x790 net/ipv4/ip_input.c:207 ip_local_deliver_finish+0x1fc/0x2f0 net/ipv4/ip_input.c:241 NF_HOOK include/linux/netfilter.h:318 [inline] ip_local_deliver+0xe8/0x1e0 net/ipv4/ip_input.c:262 dst_input include/net/dst.h:480 [inline] ip_rcv_finish+0x194/0x1c0 net/ipv4/ip_input.c:453 NF_HOOK include/linux/netfilter.h:318 [inline] ip_rcv+0x62/0x160 net/ipv4/ip_input.c:573 __netif_receive_skb_one_core net/core/dev.c:6149 [inline] __netif_receive_skb net/core/dev.c:6262 [inline] process_backlog+0x341/0x670 net/core/dev.c:6614 __napi_poll+0x5f/0x310 net/core/dev.c:7678 napi_poll net/core/dev.c:7741 [inline] net_rx_action+0x452/0x930 net/core/dev.c:7893 handle_softirqs+0xb9/0x280 kernel/softirq.c:622 do_softirq+0x45/0x60 kernel/softirq.c:523 __local_bh_enable_ip+0x70/0x80 kernel/softirq.c:450 local_bh_enable include/linux/bottom_half.h:33 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:924 [inline] __dev_queue_xmit+0x139a/0x1f20 net/core/dev.c:4856 dev_queue_xmit include/linux/netdevice.h:3384 [inline] neigh_hh_output include/net/neighbour.h:540 [inline] neigh_output include/net/neighbour.h:554 [inline] ip_finish_output2+0x705/0x8c0 net/ipv4/ip_output.c:237 __ip_finish_output net/ipv4/ip_output.c:-1 [inline] ip_finish_output+0x114/0x2a0 net/ipv4/ip_output.c:325 NF_HOOK_COND include/linux/netfilter.h:307 [inline] ip_output+0xbd/0x1c0 net/ipv4/ip_output.c:438 dst_output include/net/dst.h:470 [inline] ip_local_out net/ipv4/ip_output.c:131 [inline] __ip_queue_xmit+0xbb0/0xbf0 net/ipv4/ip_output.c:534 ip_queue_xmit+0x39/0x50 net/ipv4/ip_output.c:548 __tcp_transmit_skb+0x1af2/0x1f10 net/ipv4/tcp_output.c:1693 tcp_transmit_skb net/ipv4/tcp_output.c:1711 [inline] tcp_write_xmit+0x1597/0x3640 net/ipv4/tcp_output.c:3064 __tcp_push_pending_frames+0x6d/0x1b0 net/ipv4/tcp_output.c:3247 tcp_push_pending_frames include/net/tcp.h:2282 [inline] __tcp_sock_set_cork net/ipv4/tcp.c:3688 [inline] tcp_sock_set_cork+0xe1/0x100 net/ipv4/tcp.c:3695 rds_tcp_xmit_path_complete+0x3b/0x50 net/rds/tcp_send.c:52 rds_send_xmit+0x128c/0x16f0 net/rds/send.c:480 rds_send_worker+0x44/0x1b0 net/rds/threads.c:200 process_one_work kernel/workqueue.c:3275 [inline] process_scheduled_works+0x4cd/0x9d0 kernel/workqueue.c:3358 worker_thread+0x581/0x770 kernel/workqueue.c:3439 kthread+0x22a/0x280 kernel/kthread.c:467 ret_from_fork+0x150/0x360 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 read to 0xffff888103ccb040 of 128 bytes by interrupt on cpu 1: tcp_v6_syn_recv_sock+0x103/0xe70 net/ipv6/tcp_ipv6.c:1353 tcp_check_req+0xddd/0x1150 net/ipv4/tcp_minisocks.c:927 tcp_v4_rcv+0xeda/0x1d90 net/ipv4/tcp_ipv4.c:2238 ip_protocol_deliver_rcu+0x395/0x790 net/ipv4/ip_input.c:207 ip_local_deliver_finish+0x1fc/0x2f0 net/ipv4/ip_input.c:241 NF_HOOK include/linux/netfilter.h:318 [inline] ip_local_deliver+0xe8/0x1e0 net/ipv4/ip_input.c:262 dst_input include/net/dst.h:480 [inline] ip_rcv_finish+0x194/0x1c0 net/ipv4/ip_input.c:453 NF_HOOK include/linux/netfilter.h:318 [inline] ip_rcv+0x62/0x160 net/ipv4/ip_input.c:573 __netif_receive_skb_one_core net/core/dev.c:6149 [inline] __netif_receive_skb net/core/dev.c:6262 [inline] process_backlog+0x341/0x670 net/core/dev.c:6614 __napi_poll+0x5f/0x310 net/core/dev.c:7678 napi_poll net/core/dev.c:7741 [inline] net_rx_action+0x452/0x930 net/core/dev.c:7893 handle_softirqs+0xb9/0x280 kernel/softirq.c:622 do_softirq+0x45/0x60 kernel/softirq.c:523 __local_bh_enable_ip+0x70/0x80 kernel/softirq.c:450 local_bh_enable include/linux/bottom_half.h:33 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:924 [inline] __dev_queue_xmit+0x139a/0x1f20 net/core/dev.c:4856 dev_queue_xmit include/linux/netdevice.h:3384 [inline] neigh_hh_output include/net/neighbour.h:540 [inline] neigh_output include/net/neighbour.h:554 [inline] ip_finish_output2+0x705/0x8c0 net/ipv4/ip_output.c:237 __ip_finish_output net/ipv4/ip_output.c:-1 [inline] ip_finish_output+0x114/0x2a0 net/ipv4/ip_output.c:325 NF_HOOK_COND include/linux/netfilter.h:307 [inline] ip_output+0xbd/0x1c0 net/ipv4/ip_output.c:438 dst_output include/net/dst.h:470 [inline] ip_local_out net/ipv4/ip_output.c:131 [inline] __ip_queue_xmit+0xbb0/0xbf0 net/ipv4/ip_output.c:534 ip_queue_xmit+0x39/0x50 net/ipv4/ip_output.c:548 __tcp_transmit_skb+0x1af2/0x1f10 net/ipv4/tcp_output.c:1693 tcp_transmit_skb net/ipv4/tcp_output.c:1711 [inline] tcp_write_xmit+0x1597/0x3640 net/ipv4/tcp_output.c:3064 __tcp_push_pending_frames+0x6d/0x1b0 net/ipv4/tcp_output.c:3247 tcp_send_fin+0x58a/0x6a0 net/ipv4/tcp_output.c:3846 __tcp_close+0x67d/0x1130 net/ipv4/tcp.c:3258 tcp_close+0x28/0xd0 net/ipv4/tcp.c:3349 inet_release+0xcd/0xf0 net/ipv4/af_inet.c:437 inet6_release+0x3e/0x60 net/ipv6/af_inet6.c:487 __sock_release net/socket.c:662 [inline] sock_release+0x4b/0xe0 net/socket.c:690 rds_tcp_accept_one+0x4a1/0x830 net/rds/tcp_listen.c:345 rds_tcp_accept_worker+0x1a/0x60 net/rds/tcp.c:524 process_one_work kernel/workqueue.c:3275 [inline] process_scheduled_works+0x4cd/0x9d0 kernel/workqueue.c:3358 worker_thread+0x581/0x770 kernel/workqueue.c:3439 kthread+0x22a/0x280 kernel/kthread.c:467 ret_from_fork+0x150/0x360 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Reported by Kernel Concurrency Sanitizer on: CPU: 1 UID: 0 PID: 1918 Comm: kworker/u8:5 Tainted: G W syzkaller #0 PREEMPT(full) Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 Workqueue: krdsd rds_tcp_accept_worker ==================================================================