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: 29238 Comm: syz-executor.5 Not tainted 6.6.0-rc6-syzkaller-01701-g92fc97ae9cfd #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023 RIP: 0010:ccid_hc_tx_send_packet net/dccp/ccid.h:166 [inline] RIP: 0010:dccp_write_xmit+0x66/0x1d0 net/dccp/output.c:356 Code: 00 48 85 c0 49 89 c4 0f 84 03 01 00 00 e8 82 71 0b f8 41 80 3e 00 0f 85 45 01 00 00 48 8b 9d f8 08 00 00 48 89 d8 48 c1 e8 03 <42> 80 3c 28 00 0f 85 1f 01 00 00 48 8b 1b 48 8d bb b0 00 00 00 48 RSP: 0018:ffffc90004a97870 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffff88807c701dc0 RSI: ffffffff897c63de RDI: ffff88814ab72040 RBP: ffff88814ab72040 R08: 0000000000000001 R09: fffffbfff233a3e7 R10: ffffffff919d1f3f R11: 1ffffffff22581f7 R12: ffff888077e77280 R13: dffffc0000000000 R14: ffffed102956e527 R15: ffff88814ab72938 FS: 00007fbb50a626c0(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005555569b48f8 CR3: 0000000074426000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: dccp_sendmsg+0x968/0xcc0 net/dccp/proto.c:801 inet_sendmsg+0x9d/0xe0 net/ipv4/af_inet.c:847 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0xd5/0x180 net/socket.c:745 ____sys_sendmsg+0x2ac/0x940 net/socket.c:2558 ___sys_sendmsg+0x135/0x1d0 net/socket.c:2612 __sys_sendmmsg+0x1a1/0x450 net/socket.c:2698 __do_sys_sendmmsg net/socket.c:2727 [inline] __se_sys_sendmmsg net/socket.c:2724 [inline] __x64_sys_sendmmsg+0x9c/0x100 net/socket.c:2724 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7fbb4fc7cae9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fbb50a620c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007fbb4fd9c120 RCX: 00007fbb4fc7cae9 RDX: 0000000000000002 RSI: 00000000200003c0 RDI: 0000000000000003 RBP: 00007fbb4fcc847a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007fbb4fd9c120 R15: 00007ffc37e84ac8 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:ccid_hc_tx_send_packet net/dccp/ccid.h:166 [inline] RIP: 0010:dccp_write_xmit+0x66/0x1d0 net/dccp/output.c:356 Code: 00 48 85 c0 49 89 c4 0f 84 03 01 00 00 e8 82 71 0b f8 41 80 3e 00 0f 85 45 01 00 00 48 8b 9d f8 08 00 00 48 89 d8 48 c1 e8 03 <42> 80 3c 28 00 0f 85 1f 01 00 00 48 8b 1b 48 8d bb b0 00 00 00 48 RSP: 0018:ffffc90004a97870 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffff88807c701dc0 RSI: ffffffff897c63de RDI: ffff88814ab72040 RBP: ffff88814ab72040 R08: 0000000000000001 R09: fffffbfff233a3e7 R10: ffffffff919d1f3f R11: 1ffffffff22581f7 R12: ffff888077e77280 R13: dffffc0000000000 R14: ffffed102956e527 R15: ffff88814ab72938 FS: 00007fbb50a626c0(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9bcb8ffc83 CR3: 0000000074426000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 00 48 85 add %cl,-0x7b(%rax) 3: c0 49 89 c4 rorb $0xc4,-0x77(%rcx) 7: 0f 84 03 01 00 00 je 0x110 d: e8 82 71 0b f8 call 0xf80b7194 12: 41 80 3e 00 cmpb $0x0,(%r14) 16: 0f 85 45 01 00 00 jne 0x161 1c: 48 8b 9d f8 08 00 00 mov 0x8f8(%rbp),%rbx 23: 48 89 d8 mov %rbx,%rax 26: 48 c1 e8 03 shr $0x3,%rax * 2a: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1) <-- trapping instruction 2f: 0f 85 1f 01 00 00 jne 0x154 35: 48 8b 1b mov (%rbx),%rbx 38: 48 8d bb b0 00 00 00 lea 0xb0(%rbx),%rdi 3f: 48 rex.W