netlink: 44 bytes leftover after parsing attributes in process `syz.2.13'. ------------[ cut here ]------------ memcpy: detected field-spanning write (size 32) of single field "&new->sel" at net/sched/cls_u32.c:853 (size 16) WARNING: CPU: 1 PID: 4431 at net/sched/cls_u32.c:853 u32_init_knode net/sched/cls_u32.c:853 [inline] WARNING: CPU: 1 PID: 4431 at net/sched/cls_u32.c:853 u32_change+0x1698/0x1f18 net/sched/cls_u32.c:919 Modules linked in: CPU: 1 PID: 4431 Comm: syz.2.13 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/26/2026 pstate: 62400005 (nZCv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--) pc : u32_init_knode net/sched/cls_u32.c:853 [inline] pc : u32_change+0x1698/0x1f18 net/sched/cls_u32.c:919 lr : u32_init_knode net/sched/cls_u32.c:853 [inline] lr : u32_change+0x1698/0x1f18 net/sched/cls_u32.c:919 sp : ffff800020f86be0 x29: ffff800020f86d40 x28: ffff0000c2f08400 x27: 0000000000000000 x26: 1fffe000185e108d x25: ffff0000c2f07000 x24: ffff0000c086fa00 x23: 0000000000000010 x22: ffff7000041f0d8c x21: dfff800000000000 x20: ffff800020f87400 x19: ffff800017bea000 x18: ffff800011b9bf60 x17: 1fffe00033eaa57e x16: ffff8000082d92bc x15: 0000000040000000 x14: 0000000000000001 x13: 1fffe00033eacc30 x12: 0000000000ff0100 x11: ff0080000a8de2c4 x10: 0000000000000003 x9 : a48f2808e78d1200 x8 : a48f2808e78d1200 x7 : ffff800008257984 x6 : 0000000000000000 x5 : 0000000000000080 x4 : 0000000000000001 x3 : 0000000000000000 x2 : 0000000000000006 x1 : ffff800011b9da80 x0 : ffff80018a3dd000 Call trace: u32_init_knode net/sched/cls_u32.c:853 [inline] u32_change+0x1698/0x1f18 net/sched/cls_u32.c:919 tc_new_tfilter+0xf60/0x1474 net/sched/cls_api.c:2194 rtnetlink_rcv_msg+0x6d8/0xcdc net/core/rtnetlink.c:6141 netlink_rcv_skb+0x218/0x3e8 net/netlink/af_netlink.c:2511 rtnetlink_rcv+0x28/0x38 net/core/rtnetlink.c:6168 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x60c/0x814 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x6f4/0x9c0 net/netlink/af_netlink.c:1872 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg net/socket.c:730 [inline] ____sys_sendmsg+0x5c8/0x938 net/socket.c:2518 ___sys_sendmsg net/socket.c:2572 [inline] __sys_sendmmsg+0x344/0x834 net/socket.c:2658 __do_sys_sendmmsg net/socket.c:2687 [inline] __se_sys_sendmmsg net/socket.c:2684 [inline] __arm64_sys_sendmmsg+0xa0/0xbc net/socket.c:2684 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 irq event stamp: 888 hardirqs last enabled at (887): [] raw_spin_rq_unlock_irq kernel/sched/sched.h:1374 [inline] hardirqs last enabled at (887): [] finish_lock_switch+0xb0/0x1c4 kernel/sched/core.c:5004 hardirqs last disabled at (888): [] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:405 softirqs last enabled at (854): [] softirq_handle_end kernel/softirq.c:439 [inline] softirqs last enabled at (854): [] handle_softirqs+0xaec/0xc60 kernel/softirq.c:624 softirqs last disabled at (835): [] __do_softirq+0x14/0x20 kernel/softirq.c:630 ---[ end trace 0000000000000000 ]--- Zero length message leads to an empty skb