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+0x263/0x280 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 ================================================================== BUG: KCSAN: data-race in _prb_read_valid / data_alloc write to 0xffffffff86c7a218 of 8 bytes by task 55 on cpu 1: data_alloc+0x310/0x390 kernel/printk/printk_ringbuffer.c:1129 prb_reserve+0x8d7/0xae0 kernel/printk/printk_ringbuffer.c:1724 vprintk_store+0x54a/0x910 kernel/printk/printk.c:2354 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 __netdev_printk+0x310/0x370 net/core/dev.c:12954 netdev_info+0xa6/0xd0 net/core/dev.c:13001 __dev_set_promiscuity+0x1fb/0x3f0 net/core/dev.c:9588 netif_set_promiscuity+0x39/0x90 net/core/dev.c:9623 dev_set_promiscuity+0xc1/0x170 net/core/dev_api.c:287 hsr_del_port+0x13b/0x1a0 net/hsr/hsr_slave.c:244 hsr_del_ports+0x31/0xc0 net/hsr/hsr_device.c:471 hsr_dellink+0x5b/0xa0 net/hsr/hsr_netlink.c:142 default_device_exit_batch+0x45c/0x640 net/core/dev.c:13076 ops_exit_list net/core/net_namespace.c:205 [inline] ops_undo_list+0x2ca/0x420 net/core/net_namespace.c:252 cleanup_net+0x37c/0x5b0 net/core/net_namespace.c:704 process_one_work kernel/workqueue.c:3276 [inline] process_scheduled_works+0x513/0xa10 kernel/workqueue.c:3359 worker_thread+0x58a/0x780 kernel/workqueue.c:3440 kthread+0x22a/0x280 kernel/kthread.c:436 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 0xffffffff86c7a218 of 16 bytes by task 17102 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/0x950 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+0x88b/0x910 kernel/printk/printk.c:2381 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 printk_stack_address arch/x86/kernel/dumpstack.c:70 [inline] __show_trace_log_lvl+0x460/0x560 arch/x86/kernel/dumpstack.c:282 __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+0x263/0x280 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 copy_from_user_iter lib/iov_iter.c:50 [inline] iterate_ubuf include/linux/iov_iter.h:30 [inline] iterate_and_advance2 include/linux/iov_iter.h:302 [inline] iterate_and_advance include/linux/iov_iter.h:330 [inline] __copy_from_iter lib/iov_iter.c:261 [inline] _copy_from_iter+0xcf/0xea0 lib/iov_iter.c:272 copy_from_iter include/linux/uio.h:228 [inline] copy_from_iter_full include/linux/uio.h:245 [inline] memcpy_from_msg include/linux/skbuff.h:4273 [inline] netlink_sendmsg+0x4ae/0x6f0 net/netlink/af_netlink.c:1879 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0x563/0x5b0 net/socket.c:2592 ___sys_sendmsg+0x195/0x1e0 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+0x194c/0x3020 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x12c/0x370 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: 17102 Comm: syz.5.4160 Tainted: G W syzkaller #0 PREEMPT(full) Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 ================================================================== copy_from_user_iter lib/iov_iter.c:50 [inline] iterate_ubuf include/linux/iov_iter.h:30 [inline] iterate_and_advance2 include/linux/iov_iter.h:302 [inline] iterate_and_advance include/linux/iov_iter.h:330 [inline] __copy_from_iter lib/iov_iter.c:261 [inline] _copy_from_iter+0xcf/0xea0 lib/iov_iter.c:272 copy_from_iter include/linux/uio.h:228 [inline] copy_from_iter_full include/linux/uio.h:245 [inline] memcpy_from_msg include/linux/skbuff.h:4273 [inline] netlink_sendmsg+0x4ae/0x6f0 net/netlink/af_netlink.c:1879 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0x563/0x5b0 net/socket.c:2592 ___sys_sendmsg+0x195/0x1e0 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+0x194c/0x3020 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x12c/0x370 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f2adefec819 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f2adda3f028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f2adf265fa0 RCX: 00007f2adefec819 RDX: 0000000000008804 RSI: 0000200000000ec0 RDI: 0000000000000003 RBP: 00007f2adda3f090 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007f2adf266038 R14: 00007f2adf265fa0 R15: 00007fff5149d268