Oops: general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] CPU: 2 UID: 0 PID: 51 Comm: kworker/2:1H Not tainted 6.13.0-rc5-syzkaller-00012-g0bc21e701a6f #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Workqueue: 0x0 (events_highpri) RIP: 0010:_compound_head include/linux/page-flags.h:242 [inline] RIP: 0010:get_page include/linux/mm.h:1461 [inline] RIP: 0010:__skb_frag_ref include/linux/skbuff_ref.h:20 [inline] RIP: 0010:skb_frag_ref include/linux/skbuff_ref.h:32 [inline] RIP: 0010:pskb_expand_head+0x8ac/0x1170 net/core/skbuff.c:2300 Code: 41 83 e7 01 4c 89 fe e8 82 47 a1 f8 4d 85 ff 0f 85 c3 02 00 00 e8 04 45 a1 f8 e8 ff 44 a1 f8 48 8d 7d 08 48 89 f8 48 c1 e8 03 <42> 80 3c 20 00 0f 85 28 07 00 00 4c 8b 7d 08 31 ff 4c 89 fb 83 e3 RSP: 0018:ffffc90000548908 EFLAGS: 00010202 RAX: 0000000000000001 RBX: ffff8880256d9680 RCX: ffffffff88f80aae RDX: ffff88801cf18000 RSI: ffffffff88f80ac1 RDI: 0000000000000008 RBP: 0000000000000000 R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000b8f R12: dffffc0000000000 R13: 0000000000000000 R14: 0000000000000030 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff88802b600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020f0c000 CR3: 000000006f3be000 CR4: 0000000000352ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __skb_unclone_keeptruesize+0x91/0x280 net/core/skbuff.c:2375 skb_unclone_keeptruesize include/linux/skbuff.h:1998 [inline] __tcp_retransmit_skb.part.0+0xc58/0x2680 net/ipv4/tcp_output.c:3376 __tcp_retransmit_skb net/ipv4/tcp_output.c:3330 [inline] tcp_send_loss_probe+0x454/0xb00 net/ipv4/tcp_output.c:2982 tcp_write_timer_handler net/ipv4/tcp_timer.c:710 [inline] tcp_write_timer_handler+0x59d/0xa70 net/ipv4/tcp_timer.c:688 tcp_write_timer+0x157/0x2f0 net/ipv4/tcp_timer.c:735 call_timer_fn+0x1a0/0x610 kernel/time/timer.c:1793 expire_timers kernel/time/timer.c:1844 [inline] __run_timers+0x6e8/0x930 kernel/time/timer.c:2418 __run_timer_base kernel/time/timer.c:2430 [inline] __run_timer_base kernel/time/timer.c:2422 [inline] run_timer_base+0x114/0x190 kernel/time/timer.c:2439 run_timer_softirq+0x1a/0x40 kernel/time/timer.c:2449 handle_softirqs+0x213/0x8f0 kernel/softirq.c:561 __do_softirq kernel/softirq.c:595 [inline] invoke_softirq kernel/softirq.c:435 [inline] __irq_exit_rcu+0x109/0x170 kernel/softirq.c:662 irq_exit_rcu+0x9/0x30 kernel/softirq.c:678 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:finish_task_switch.isra.0+0x220/0xcc0 kernel/sched/core.c:5243 Code: a9 0a 00 00 44 8b 0d 23 b3 b4 0e 45 85 c9 0f 85 c0 01 00 00 48 89 df e8 ae f8 ff ff e8 49 89 38 00 fb 65 48 8b 1d f0 74 9b 7e <48> 8d bb f8 15 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 RSP: 0018:ffffc90000727c00 EFLAGS: 00000202 RAX: 00000000001102ef RBX: ffff88801cf18000 RCX: 1ffffffff2039441 RDX: 0000000000000000 RSI: ffffffff8b4cd300 RDI: ffffffff8bb17100 RBP: ffffc90000727c48 R08: 0000000000000001 R09: 0000000000000001 R10: ffffffff901ce557 R11: 0000000000000000 R12: ffff88802b63fb20 R13: ffff888025a10000 R14: 0000000000000000 R15: ffff88802b63ed00 context_switch kernel/sched/core.c:5372 [inline] __schedule+0xe60/0x5ad0 kernel/sched/core.c:6756 __schedule_loop kernel/sched/core.c:6833 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6848 worker_thread+0x2de/0xf00 kernel/workqueue.c:3406 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:_compound_head include/linux/page-flags.h:242 [inline] RIP: 0010:get_page include/linux/mm.h:1461 [inline] RIP: 0010:__skb_frag_ref include/linux/skbuff_ref.h:20 [inline] RIP: 0010:skb_frag_ref include/linux/skbuff_ref.h:32 [inline] RIP: 0010:pskb_expand_head+0x8ac/0x1170 net/core/skbuff.c:2300 Code: 41 83 e7 01 4c 89 fe e8 82 47 a1 f8 4d 85 ff 0f 85 c3 02 00 00 e8 04 45 a1 f8 e8 ff 44 a1 f8 48 8d 7d 08 48 89 f8 48 c1 e8 03 <42> 80 3c 20 00 0f 85 28 07 00 00 4c 8b 7d 08 31 ff 4c 89 fb 83 e3 RSP: 0018:ffffc90000548908 EFLAGS: 00010202 RAX: 0000000000000001 RBX: ffff8880256d9680 RCX: ffffffff88f80aae RDX: ffff88801cf18000 RSI: ffffffff88f80ac1 RDI: 0000000000000008 RBP: 0000000000000000 R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000b8f R12: dffffc0000000000 R13: 0000000000000000 R14: 0000000000000030 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff88802b600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020f0c000 CR3: 000000006f3be000 CR4: 0000000000352ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 41 83 e7 01 and $0x1,%r15d 4: 4c 89 fe mov %r15,%rsi 7: e8 82 47 a1 f8 call 0xf8a1478e c: 4d 85 ff test %r15,%r15 f: 0f 85 c3 02 00 00 jne 0x2d8 15: e8 04 45 a1 f8 call 0xf8a1451e 1a: e8 ff 44 a1 f8 call 0xf8a1451e 1f: 48 8d 7d 08 lea 0x8(%rbp),%rdi 23: 48 89 f8 mov %rdi,%rax 26: 48 c1 e8 03 shr $0x3,%rax * 2a: 42 80 3c 20 00 cmpb $0x0,(%rax,%r12,1) <-- trapping instruction 2f: 0f 85 28 07 00 00 jne 0x75d 35: 4c 8b 7d 08 mov 0x8(%rbp),%r15 39: 31 ff xor %edi,%edi 3b: 4c 89 fb mov %r15,%rbx 3e: 83 .byte 0x83 3f: e3 .byte 0xe3