general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 1 PID: 20510 Comm: syz.9.3968 Not tainted 6.1.147-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:dequeue_head net/sched/sch_fq_codel.c:120 [inline] RIP: 0010:fq_codel_drop net/sched/sch_fq_codel.c:168 [inline] RIP: 0010:fq_codel_enqueue+0xd2d/0x1590 net/sched/sch_fq_codel.c:230 Code: 24 08 48 8b 44 24 20 80 3c 10 00 74 12 4c 89 ef e8 38 c3 82 f9 48 ba 00 00 00 00 00 fc ff df 4d 8b 65 00 4c 89 e0 48 c1 e8 03 <80> 3c 10 00 74 12 4c 89 e7 e8 15 c3 82 f9 48 ba 00 00 00 00 00 fc RSP: 0018:ffffc900001e0900 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 1ffff9200003c170 RCX: 1ffff1100a55de5a RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc900001e0a50 R08: dffffc0000000000 R09: fffffbfff215ba8e R10: fffffbfff215ba8e R11: 1ffffffff215ba8d R12: 0000000000000000 R13: ffff888052aee800 R14: 0000000000000000 R15: 0000000000000000 FS: 00007fca579686c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 0000000073eb2000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: qdisc_enqueue include/net/sch_generic.h:816 [inline] netem_dequeue+0xcfc/0x13c0 net/sched/sch_netem.c:737 dequeue_skb net/sched/sch_generic.c:292 [inline] qdisc_restart net/sched/sch_generic.c:397 [inline] __qdisc_run+0x247/0x15f0 net/sched/sch_generic.c:415 qdisc_run+0xc2/0x230 include/net/pkt_sched.h:126 net_tx_action+0x764/0x920 net/core/dev.c:5166 handle_softirqs+0x2a1/0x920 kernel/softirq.c:596 __do_softirq kernel/softirq.c:630 [inline] invoke_softirq kernel/softirq.c:470 [inline] __irq_exit_rcu+0x12f/0x220 kernel/softirq.c:679 irq_exit_rcu+0x5/0x20 kernel/softirq.c:691 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:lock_acquire+0x20f/0x490 kernel/locking/lockdep.c:5666 Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f5 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 66 43 c7 44 3d 09 00 00 43 c6 44 3d 0b RSP: 0018:ffffc9000518f720 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 25014f78ee1d5d00 RDX: 0000000000000000 RSI: ffffffff8a8c15e0 RDI: ffffffff8adef320 RBP: ffffc9000518f828 R08: dffffc0000000000 R09: fffffbfff215ba49 R10: fffffbfff215ba49 R11: 1ffffffff215ba48 R12: 0000000000000001 R13: 1ffff92000a31ef0 R14: 0000000000000246 R15: dffffc0000000000 rcu_lock_acquire include/linux/rcupdate.h:350 [inline] rcu_read_lock include/linux/rcupdate.h:791 [inline] filemap_map_pages+0x1af/0x10d0 mm/filemap.c:3444 do_fault_around mm/memory.c:4600 [inline] do_read_fault mm/memory.c:4626 [inline] do_fault mm/memory.c:4760 [inline] handle_pte_fault mm/memory.c:5031 [inline] __handle_mm_fault mm/memory.c:5173 [inline] handle_mm_fault+0x2889/0x3e70 mm/memory.c:5294 faultin_page mm/gup.c:1026 [inline] __get_user_pages+0x3ff/0xeb0 mm/gup.c:1250 populate_vma_page_range+0x214/0x2b0 mm/gup.c:1607 __mm_populate+0x248/0x370 mm/gup.c:1721 mm_populate include/linux/mm.h:2826 [inline] vm_mmap_pgoff+0x203/0x2b0 mm/util.c:525 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fca56b8ebe9 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:00007fca57968038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007fca56db5fa0 RCX: 00007fca56b8ebe9 RDX: b635773f06ebbee2 RSI: 0000000000b36000 RDI: 0000200000000000 RBP: 00007fca56c11e19 R08: ffffffffffffffff R09: 0000000000000000 R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fca56db6038 R14: 00007fca56db5fa0 R15: 00007ffcb04eaa58 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:dequeue_head net/sched/sch_fq_codel.c:120 [inline] RIP: 0010:fq_codel_drop net/sched/sch_fq_codel.c:168 [inline] RIP: 0010:fq_codel_enqueue+0xd2d/0x1590 net/sched/sch_fq_codel.c:230 Code: 24 08 48 8b 44 24 20 80 3c 10 00 74 12 4c 89 ef e8 38 c3 82 f9 48 ba 00 00 00 00 00 fc ff df 4d 8b 65 00 4c 89 e0 48 c1 e8 03 <80> 3c 10 00 74 12 4c 89 e7 e8 15 c3 82 f9 48 ba 00 00 00 00 00 fc RSP: 0018:ffffc900001e0900 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 1ffff9200003c170 RCX: 1ffff1100a55de5a RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc900001e0a50 R08: dffffc0000000000 R09: fffffbfff215ba8e R10: fffffbfff215ba8e R11: 1ffffffff215ba8d R12: 0000000000000000 R13: ffff888052aee800 R14: 0000000000000000 R15: 0000000000000000 FS: 00007fca579686c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 0000000073eb2000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 24 08 and $0x8,%al 2: 48 8b 44 24 20 mov 0x20(%rsp),%rax 7: 80 3c 10 00 cmpb $0x0,(%rax,%rdx,1) b: 74 12 je 0x1f d: 4c 89 ef mov %r13,%rdi 10: e8 38 c3 82 f9 call 0xf982c34d 15: 48 ba 00 00 00 00 00 movabs $0xdffffc0000000000,%rdx 1c: fc ff df 1f: 4d 8b 65 00 mov 0x0(%r13),%r12 23: 4c 89 e0 mov %r12,%rax 26: 48 c1 e8 03 shr $0x3,%rax * 2a: 80 3c 10 00 cmpb $0x0,(%rax,%rdx,1) <-- trapping instruction 2e: 74 12 je 0x42 30: 4c 89 e7 mov %r12,%rdi 33: e8 15 c3 82 f9 call 0xf982c34d 38: 48 rex.W 39: ba 00 00 00 00 mov $0x0,%edx 3e: 00 fc add %bh,%ah