BUG: kernel NULL pointer dereference, address: 0000000000000050 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 1165db067 P4D 1165db067 PUD 0 Oops: Oops: 0000 [#1] SMP NOPTI CPU: 1 UID: 0 PID: 4812 Comm: syz.2.16 Not tainted 6.16.0-rc3-syzkaller #0 PREEMPT(undef) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:__list_del_entry_valid_or_report+0x8/0x100 lib/list_debug.c:50 Code: ff 90 0f 0b 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 54 55 53 <48> 8b 2f 48 89 fb 4c 8b 67 08 48 85 ed 74 41 4d 85 e4 74 4e 48 b8 RSP: 0018:ffffc90001aa77e8 EFLAGS: 00010293 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff8280198d RDX: ffff88811a378000 RSI: ffffffff82800d94 RDI: 0000000000000050 RBP: 00000000000a0000 R08: 0000000000000005 R09: 0000000000000000 R10: 00000000000a0000 R11: 00000000c002eb3c R12: 0000000000000050 R13: 0000000000000000 R14: ffff888123dcd000 R15: 0000000000000000 FS: 00007fb700b7f6c0(0000) GS:ffff8882b2c40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000050 CR3: 0000000120ce7000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __list_del_entry_valid include/linux/list.h:124 [inline] __list_del_entry include/linux/list.h:215 [inline] list_del_init include/linux/list.h:287 [inline] drr_qlen_notify+0x1c/0x60 net/sched/sch_drr.c:238 qdisc_tree_reduce_backlog+0xbc/0x1d0 net/sched/sch_api.c:811 pie_change+0x2e5/0x3a0 net/sched/sch_pie.c:204 pie_init+0x10b/0x150 net/sched/sch_pie.c:456 qdisc_create+0x1f9/0x770 net/sched/sch_api.c:1324 __tc_modify_qdisc net/sched/sch_api.c:1749 [inline] tc_modify_qdisc+0x6c8/0xec0 net/sched/sch_api.c:1813 rtnetlink_rcv_msg+0x26f/0x6d0 net/core/rtnetlink.c:6953 netlink_rcv_skb+0x93/0x1d0 net/netlink/af_netlink.c:2534 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline] netlink_unicast+0x42c/0x550 net/netlink/af_netlink.c:1339 netlink_sendmsg+0x335/0x6a0 net/netlink/af_netlink.c:1883 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg net/socket.c:727 [inline] ____sys_sendmsg+0x508/0x540 net/socket.c:2566 ___sys_sendmsg+0xc8/0x130 net/socket.c:2620 __sys_sendmsg+0xc7/0x140 net/socket.c:2652 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x6d/0x310 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb70110e929 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:00007fb700b7f038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007fb701335fa0 RCX: 00007fb70110e929 RDX: 0000000000004000 RSI: 0000200000000280 RDI: 0000000000000006 RBP: 00007fb701190b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fb701335fa0 R15: 00007fff73909588 Modules linked in: CR2: 0000000000000050 ---[ end trace 0000000000000000 ]--- RIP: 0010:__list_del_entry_valid_or_report+0x8/0x100 lib/list_debug.c:50 Code: ff 90 0f 0b 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 54 55 53 <48> 8b 2f 48 89 fb 4c 8b 67 08 48 85 ed 74 41 4d 85 e4 74 4e 48 b8 RSP: 0018:ffffc90001aa77e8 EFLAGS: 00010293 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff8280198d RDX: ffff88811a378000 RSI: ffffffff82800d94 RDI: 0000000000000050 RBP: 00000000000a0000 R08: 0000000000000005 R09: 0000000000000000 R10: 00000000000a0000 R11: 00000000c002eb3c R12: 0000000000000050 R13: 0000000000000000 R14: ffff888123dcd000 R15: 0000000000000000 FS: 00007fb700b7f6c0(0000) GS:ffff8882b2c40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000050 CR3: 0000000120ce7000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: ff 90 0f 0b 66 66 call *0x66660b0f(%rax) 6: 2e 0f 1f 84 00 00 00 cs nopl 0x0(%rax,%rax,1) d: 00 00 f: 0f 1f 00 nopl (%rax) 12: 90 nop 13: 90 nop 14: 90 nop 15: 90 nop 16: 90 nop 17: 90 nop 18: 90 nop 19: 90 nop 1a: 90 nop 1b: 90 nop 1c: 90 nop 1d: 90 nop 1e: 90 nop 1f: 90 nop 20: 90 nop 21: 90 nop 22: f3 0f 1e fa endbr64 26: 41 54 push %r12 28: 55 push %rbp 29: 53 push %rbx * 2a: 48 8b 2f mov (%rdi),%rbp <-- trapping instruction 2d: 48 89 fb mov %rdi,%rbx 30: 4c 8b 67 08 mov 0x8(%rdi),%r12 34: 48 85 ed test %rbp,%rbp 37: 74 41 je 0x7a 39: 4d 85 e4 test %r12,%r12 3c: 74 4e je 0x8c 3e: 48 rex.W 3f: b8 .byte 0xb8