FAULT_INJECTION: forcing a failure. name fail_usercopy, interval 1, probability 0, space 0, times 0 ================================================================== BUG: KCSAN: data-race in _prb_read_valid / data_alloc write to 0xffffffff8687ebd8 of 8 bytes by task 14494 on cpu 1: data_alloc+0x310/0x390 kernel/printk/printk_ringbuffer.c:1129 prb_reserve+0x8d7/0xad0 kernel/printk/printk_ringbuffer.c:1724 vprintk_store+0x53c/0x830 kernel/printk/printk.c:2302 vprintk_emit+0x15a/0x5c0 kernel/printk/printk.c:2402 dev_vprintk_emit+0x242/0x2a0 drivers/base/core.c:4914 dev_printk_emit+0x84/0xb0 drivers/base/core.c:4925 __netdev_printk+0x34b/0x370 net/core/dev.c:12903 netdev_info+0x9b/0xd0 net/core/dev.c:12958 nsim_udp_tunnel_unset_port+0x190/0x1b0 drivers/net/netdevsim/udp_tunnels.c:59 udp_tunnel_nic_device_sync_one net/ipv4/udp_tunnel_nic.c:-1 [inline] udp_tunnel_nic_device_sync_by_port net/ipv4/udp_tunnel_nic.c:249 [inline] __udp_tunnel_nic_device_sync+0x567/0x9c0 net/ipv4/udp_tunnel_nic.c:292 udp_tunnel_nic_flush+0x21b/0x300 net/ipv4/udp_tunnel_nic.c:694 udp_tunnel_nic_unregister net/ipv4/udp_tunnel_nic.c:901 [inline] udp_tunnel_nic_netdevice_event+0x8c0/0xd70 net/ipv4/udp_tunnel_nic.c:942 notifier_call_chain kernel/notifier.c:85 [inline] raw_notifier_call_chain+0x6f/0x1b0 kernel/notifier.c:453 call_netdevice_notifiers_info net/core/dev.c:2230 [inline] call_netdevice_notifiers_extack net/core/dev.c:2268 [inline] call_netdevice_notifiers net/core/dev.c:2282 [inline] unregister_netdevice_many_notify+0xea0/0x16d0 net/core/dev.c:12383 unregister_netdevice_many net/core/dev.c:12446 [inline] unregister_netdevice_queue+0x1b8/0x1e0 net/core/dev.c:12260 unregister_netdevice include/linux/netdevice.h:3405 [inline] nsim_destroy+0xfa/0x2f0 drivers/net/netdevsim/netdev.c:1180 __nsim_dev_port_del+0xcf/0x110 drivers/net/netdevsim/dev.c:1528 nsim_dev_port_del_all drivers/net/netdevsim/dev.c:1540 [inline] nsim_dev_reload_destroy+0x1a3/0x2c0 drivers/net/netdevsim/dev.c:1763 nsim_dev_reload_down+0x67/0x80 drivers/net/netdevsim/dev.c:1038 devlink_reload+0xad/0x580 net/devlink/dev.c:461 devlink_nl_reload_doit+0x771/0x960 net/devlink/dev.c:584 genl_family_rcv_msg_doit+0x143/0x1b0 net/netlink/genetlink.c:1115 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline] genl_rcv_msg+0x422/0x460 net/netlink/genetlink.c:1210 netlink_rcv_skb+0x123/0x220 net/netlink/af_netlink.c:2550 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x5c0/0x690 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x58b/0x6b0 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0x145/0x180 net/socket.c:742 ____sys_sendmsg+0x31e/0x4a0 net/socket.c:2592 ___sys_sendmsg+0x17b/0x1d0 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0xd4/0x160 net/socket.c:2681 x64_sys_call+0x17ba/0x3000 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xca/0x2b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f read to 0xffffffff8687ebd8 of 16 bytes by task 14495 on cpu 0: desc_read kernel/printk/printk_ringbuffer.c:496 [inline] desc_read_finalized_seq kernel/printk/printk_ringbuffer.c:1931 [inline] prb_read kernel/printk/printk_ringbuffer.c:1979 [inline] _prb_read_valid+0x1bc/0x920 kernel/printk/printk_ringbuffer.c:2170 desc_update_last_finalized+0x8f/0x170 kernel/printk/printk_ringbuffer.c:1570 prb_final_commit+0x10d/0x150 kernel/printk/printk_ringbuffer.c:1839 vprintk_store+0x710/0x830 kernel/printk/printk.c:2328 vprintk_emit+0x15a/0x5c0 kernel/printk/printk.c:2402 vprintk_default+0x26/0x30 kernel/printk/printk.c:2441 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82 _printk+0x79/0xa0 kernel/printk/printk.c:2451 fail_dump lib/fault-inject.c:66 [inline] should_fail_ex+0x24d/0x280 lib/fault-inject.c:174 should_fail+0xb/0x20 lib/fault-inject.c:184 should_fail_usercopy+0x1a/0x20 lib/fault-inject-usercopy.c:35 _inline_copy_from_user include/linux/uaccess.h:170 [inline] _copy_from_user+0x1c/0xb0 lib/usercopy.c:18 copy_from_user include/linux/uaccess.h:223 [inline] ucma_write+0xd9/0x250 drivers/infiniband/core/ucma.c:1843 vfs_write+0x269/0x960 fs/read_write.c:684 ksys_write+0xda/0x1a0 fs/read_write.c:738 __do_sys_write fs/read_write.c:749 [inline] __se_sys_write fs/read_write.c:746 [inline] __x64_sys_write+0x40/0x50 fs/read_write.c:746 x64_sys_call+0x2847/0x3000 arch/x86/include/generated/asm/syscalls_64.h:2 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xca/0x2b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Reported by Kernel Concurrency Sanitizer on: CPU: 0 UID: 0 PID: 14495 Comm: syz.3.3890 Tainted: G W syzkaller #0 PREEMPT(voluntary) Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 ================================================================== CPU: 0 UID: 0 PID: 14495 Comm: syz.3.3890 Tainted: G W syzkaller #0 PREEMPT(voluntary) Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: __dump_stack+0x1d/0x30 lib/dump_stack.c:94 dump_stack_lvl+0x95/0xd0 lib/dump_stack.c:120 dump_stack+0x15/0x1b lib/dump_stack.c:129 fail_dump lib/fault-inject.c:73 [inline] should_fail_ex+0x265/0x280 lib/fault-inject.c:174 should_fail+0xb/0x20 lib/fault-inject.c:184 should_fail_usercopy+0x1a/0x20 lib/fault-inject-usercopy.c:35 _inline_copy_from_user include/linux/uaccess.h:170 [inline] _copy_from_user+0x1c/0xb0 lib/usercopy.c:18 copy_from_user include/linux/uaccess.h:223 [inline] ucma_write+0xd9/0x250 drivers/infiniband/core/ucma.c:1843 vfs_write+0x269/0x960 fs/read_write.c:684 ksys_write+0xda/0x1a0 fs/read_write.c:738 __do_sys_write fs/read_write.c:749 [inline] __se_sys_write fs/read_write.c:746 [inline] __x64_sys_write+0x40/0x50 fs/read_write.c:746 x64_sys_call+0x2847/0x3000 arch/x86/include/generated/asm/syscalls_64.h:2 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xca/0x2b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa81bf0f749 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fa81a96f038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fa81c165fa0 RCX: 00007fa81bf0f749 RDX: 0000000000000018 RSI: 0000200000000080 RDI: 0000000000000006 RBP: 00007fa81a96f090 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007fa81c166038 R14: 00007fa81c165fa0 R15: 00007ffd81e2e118