lowmem_reserve[]: 0 0 0 0 Node 0 DMA: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 1*1024kB (U) 1*2048kB (M) 3*4096kB (M) = 15360kB ================================================================== BUG: KCSAN: data-race in _prb_read_valid / data_alloc write to 0xffffffff86c731c8 of 8 bytes by task 68 on cpu 1: data_alloc+0x2fc/0x380 kernel/printk/printk_ringbuffer.c:1129 prb_reserve+0x8e3/0xaf0 kernel/printk/printk_ringbuffer.c:1727 vprintk_store+0x54a/0x910 kernel/printk/printk.c:2354 vprintk_emit+0x1a4/0x600 kernel/printk/printk.c:2455 dev_vprintk_emit+0x242/0x2a0 drivers/base/core.c:4996 dev_printk_emit+0x84/0xb0 drivers/base/core.c:5007 __netdev_printk+0x34b/0x370 net/core/dev.c:12958 netdev_info+0xa6/0xd0 net/core/dev.c:13013 nsim_udp_tunnel_set_port+0x135/0x150 drivers/net/netdevsim/udp_tunnels.c:31 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+0x576/0x9c0 net/ipv4/udp_tunnel_nic.c:292 udp_tunnel_nic_device_sync_work+0x5d/0x580 net/ipv4/udp_tunnel_nic.c:740 process_one_work kernel/workqueue.c:3322 [inline] process_scheduled_works+0x4d4/0x9a0 kernel/workqueue.c:3405 worker_thread+0x569/0x750 kernel/workqueue.c:3486 kthread+0x221/0x270 kernel/kthread.c:436 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 read to 0xffffffff86c731c8 of 16 bytes by task 4038 on cpu 0: desc_read kernel/printk/printk_ringbuffer.c:496 [inline] desc_read_finalized_seq kernel/printk/printk_ringbuffer.c:1934 [inline] prb_read kernel/printk/printk_ringbuffer.c:1982 [inline] _prb_read_valid+0x183/0x930 kernel/printk/printk_ringbuffer.c:2173 desc_update_last_finalized+0x8f/0x170 kernel/printk/printk_ringbuffer.c:1573 prb_final_commit+0x111/0x150 kernel/printk/printk_ringbuffer.c:1842 vprintk_store+0x6f9/0x910 kernel/printk/printk.c:2338 vprintk_emit+0x1a4/0x600 kernel/printk/printk.c:2455 vprintk_default+0x26/0x30 kernel/printk/printk.c:2494 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82 _printk+0x79/0xa0 kernel/printk/printk.c:2504 show_free_areas mm/show_mem.c:391 [inline] __show_mem+0x1240/0x14a0 mm/show_mem.c:411 warn_alloc_show_mem mm/page_alloc.c:3998 [inline] warn_alloc+0x1a1/0x1c0 mm/page_alloc.c:4024 __vmalloc_node_range_noprof+0x28b/0x11e0 mm/vmalloc.c:4047 __vmalloc_node_noprof mm/vmalloc.c:4143 [inline] __vmalloc_noprof+0xa4/0xf0 mm/vmalloc.c:4159 bpf_prog_alloc_no_stats+0x47/0x390 kernel/bpf/core.c:107 bpf_prog_alloc+0x3c/0x150 kernel/bpf/core.c:156 bpf_prog_load+0x54b/0x1100 kernel/bpf/syscall.c:3097 __sys_bpf+0xbae/0xc30 kernel/bpf/syscall.c:6418 __do_sys_bpf kernel/bpf/syscall.c:6537 [inline] __se_sys_bpf kernel/bpf/syscall.c:6534 [inline] __x64_sys_bpf+0x69/0x80 kernel/bpf/syscall.c:6534 x64_sys_call+0x10cb/0x3020 arch/x86/include/generated/asm/syscalls_64.h:322 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x136/0x3c0 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: 4038 Comm: syz.3.10483 Tainted: G W syzkaller #0 PREEMPT(lazy) Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 ================================================================== Node 0 DMA32: 3*4kB (M) 1*8kB (M) 4*16kB (M) 2*32kB (M) 3*64kB (M) 2*128kB (M) 2*256kB (M) 2*512kB (M) 3*1024kB (M) 3*2048kB (M) 716*4096kB (M) = 2944084kB Node 0 Normal: 3623*4kB (UME) 2854*8kB (UME) 1814*16kB (UME) 1175*32kB (UME) 729*64kB (UME) 280*128kB (UM) 162*256kB (UME) 71*512kB (UM) 44*1024kB (UM) 45*2048kB (UM) 991*4096kB (UM) = 4460620kB Node 0 hugepages_total=4 hugepages_free=4 hugepages_surp=0 hugepages_size=2048kB 33777 total pagecache pages 3 pages in swap cache Free swap = 124984kB Total swap = 124996kB 2097051 pages RAM 0 pages HighMem/MovableOnly 81724 pages reserved