should_failslab+0x8c/0xb0 mm/failslab.c:46 slab_pre_alloc_hook mm/slub.c:4133 [inline] slab_alloc_node mm/slub.c:4209 [inline] __kmalloc_cache_noprof+0x4c/0x320 mm/slub.c:4391 ================================================================== BUG: KCSAN: data-race in data_push_tail / string write to 0xffffffff88e1cec8 of 1 bytes by task 3414 on cpu 1: string_nocheck lib/vsprintf.c:657 [inline] string+0x187/0x220 lib/vsprintf.c:735 vsnprintf+0x532/0x890 lib/vsprintf.c:2926 vscnprintf+0x41/0x90 lib/vsprintf.c:2991 printk_sprint+0x30/0x2d0 kernel/printk/printk.c:2216 vprintk_store+0x599/0x860 kernel/printk/printk.c:2336 vprintk_emit+0x178/0x650 kernel/printk/printk.c:2426 dev_vprintk_emit+0x242/0x2a0 drivers/base/core.c:4914 dev_printk_emit+0x84/0xb0 drivers/base/core.c:4925 __netdev_printk+0x35c/0x3e0 net/core/dev.c:12580 netdev_info+0x9b/0xd0 net/core/dev.c:12635 nsim_udp_tunnel_set_port+0x13b/0x160 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+0x564/0x9c0 net/ipv4/udp_tunnel_nic.c:292 udp_tunnel_nic_device_sync_work+0x5d/0x5f0 net/ipv4/udp_tunnel_nic.c:740 process_one_work kernel/workqueue.c:3236 [inline] process_scheduled_works+0x4cb/0x9d0 kernel/workqueue.c:3319 worker_thread+0x582/0x770 kernel/workqueue.c:3400 kthread+0x489/0x510 kernel/kthread.c:463 ret_from_fork+0xda/0x150 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 read to 0xffffffff88e1cec8 of 8 bytes by task 6003 on cpu 0: data_make_reusable kernel/printk/printk_ringbuffer.c:594 [inline] data_push_tail+0xfd/0x420 kernel/printk/printk_ringbuffer.c:679 data_alloc+0xbf/0x2b0 kernel/printk/printk_ringbuffer.c:1054 prb_reserve+0x808/0xaf0 kernel/printk/printk_ringbuffer.c:1669 vprintk_store+0x56d/0x860 kernel/printk/printk.c:2326 vprintk_emit+0x178/0x650 kernel/printk/printk.c:2426 vprintk_default+0x26/0x30 kernel/printk/printk.c:2465 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82 _printk+0x79/0xa0 kernel/printk/printk.c:2475 printk_stack_address arch/x86/kernel/dumpstack.c:70 [inline] show_trace_log_lvl+0x4e3/0x560 arch/x86/kernel/dumpstack.c:282 __dump_stack+0x1d/0x30 lib/dump_stack.c:94 dump_stack_lvl+0xe8/0x140 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_failslab+0x8c/0xb0 mm/failslab.c:46 slab_pre_alloc_hook mm/slub.c:4133 [inline] slab_alloc_node mm/slub.c:4209 [inline] __kmalloc_cache_noprof+0x4c/0x320 mm/slub.c:4391 kmalloc_noprof include/linux/slab.h:905 [inline] alloc_name mm/memfd.c:410 [inline] __do_sys_memfd_create mm/memfd.c:481 [inline] __se_sys_memfd_create+0x1cc/0x590 mm/memfd.c:469 __x64_sys_memfd_create+0x31/0x40 mm/memfd.c:469 x64_sys_call+0x2abe/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:320 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f value changed: 0x00000000ffffe0ad -> 0x68746520336d6973 Reported by Kernel Concurrency Sanitizer on: CPU: 0 UID: 0 PID: 6003 Comm: syz.4.607 Not tainted 6.17.0-rc1-syzkaller-00038-g0cc53520e68b #0 PREEMPT(voluntary) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 ================================================================== kmalloc_noprof include/linux/slab.h:905 [inline] alloc_name mm/memfd.c:410 [inline] __do_sys_memfd_create mm/memfd.c:481 [inline] __se_sys_memfd_create+0x1cc/0x590 mm/memfd.c:469 __x64_sys_memfd_create+0x31/0x40 mm/memfd.c:469 x64_sys_call+0x2abe/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:320 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f186317ebe9 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:00007f1861bdee18 EFLAGS: 00000202 ORIG_RAX: 000000000000013f RAX: ffffffffffffffda RBX: 0000000000000473 RCX: 00007f186317ebe9 RDX: 00007f1861bdeef0 RSI: 0000000000000000 RDI: 00007f18632027e8 RBP: 0000200000000640 R08: 00007f1861bdebb7 R09: 00007f1861bdee40 R10: 000000000000000a R11: 0000000000000202 R12: 0000200000000000 R13: 00007f1861bdeef0 R14: 00007f1861bdeeb0 R15: 00002000000005c0