general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 0 PID: 6142 Comm: syz-executor.0 Not tainted 6.7.0-rc2-syzkaller-00206-gb46ae77f6787 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023 RIP: 0010:ccid_hc_tx_send_packet net/dccp/ccid.h:166 [inline] RIP: 0010:dccp_write_xmit+0x6f/0x220 net/dccp/output.c:356 Code: 03 48 89 44 24 08 4c 89 2c 24 48 8b 44 24 08 80 3c 28 00 74 08 48 89 df e8 6e 94 99 f7 49 89 df 48 8b 1b 48 89 d8 48 c1 e8 03 <80> 3c 28 00 74 08 48 89 df e8 53 94 99 f7 48 8b 1b b8 b0 00 00 00 RSP: 0018:ffffc900057d7a18 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88807eaaca00 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88814b162900 RBP: dffffc0000000000 R08: ffffffff8a51eda1 R09: 1ffffffff21ba883 R10: dffffc0000000000 R11: fffffbfff21ba884 R12: ffff88807eaaca00 R13: ffff88814b162900 R14: ffff88814b163250 R15: ffff88814b1631f0 FS: 00007fbdf68fb6c0(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fbdf47fed58 CR3: 00000000281d3000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: dccp_sendmsg+0x759/0xb70 net/dccp/proto.c:801 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] sock_write_iter+0x39a/0x520 net/socket.c:1158 call_write_iter include/linux/fs.h:2020 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x792/0xb20 fs/read_write.c:584 ksys_write+0x1a0/0x2c0 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x45/0x110 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x63/0x6b RIP: 0033:0x7fbdf5c7cae9 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:00007fbdf68fb0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fbdf5d9c050 RCX: 00007fbdf5c7cae9 RDX: 00000000000008a8 RSI: 0000000020000900 RDI: 0000000000000003 RBP: 00007fbdf5cc847a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000006e R14: 00007fbdf5d9c050 R15: 00007ffd72ad5b18 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:ccid_hc_tx_send_packet net/dccp/ccid.h:166 [inline] RIP: 0010:dccp_write_xmit+0x6f/0x220 net/dccp/output.c:356 Code: 03 48 89 44 24 08 4c 89 2c 24 48 8b 44 24 08 80 3c 28 00 74 08 48 89 df e8 6e 94 99 f7 49 89 df 48 8b 1b 48 89 d8 48 c1 e8 03 <80> 3c 28 00 74 08 48 89 df e8 53 94 99 f7 48 8b 1b b8 b0 00 00 00 RSP: 0018:ffffc900057d7a18 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88807eaaca00 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88814b162900 RBP: dffffc0000000000 R08: ffffffff8a51eda1 R09: 1ffffffff21ba883 R10: dffffc0000000000 R11: fffffbfff21ba884 R12: ffff88807eaaca00 R13: ffff88814b162900 R14: ffff88814b163250 R15: ffff88814b1631f0 FS: 00007fbdf68fb6c0(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b31920000 CR3: 00000000281d3000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 03 48 89 add -0x77(%rax),%ecx 3: 44 24 08 rex.R and $0x8,%al 6: 4c 89 2c 24 mov %r13,(%rsp) a: 48 8b 44 24 08 mov 0x8(%rsp),%rax f: 80 3c 28 00 cmpb $0x0,(%rax,%rbp,1) 13: 74 08 je 0x1d 15: 48 89 df mov %rbx,%rdi 18: e8 6e 94 99 f7 call 0xf799948b 1d: 49 89 df mov %rbx,%r15 20: 48 8b 1b mov (%rbx),%rbx 23: 48 89 d8 mov %rbx,%rax 26: 48 c1 e8 03 shr $0x3,%rax * 2a: 80 3c 28 00 cmpb $0x0,(%rax,%rbp,1) <-- trapping instruction 2e: 74 08 je 0x38 30: 48 89 df mov %rbx,%rdi 33: e8 53 94 99 f7 call 0xf799948b 38: 48 8b 1b mov (%rbx),%rbx 3b: b8 b0 00 00 00 mov $0xb0,%eax