syzbot has found a reproducer for the following issue on: HEAD commit: d2f51b3516da Merge tag 'rtc-6.7' of git://git.kernel.org/p.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=16675f40e80000 kernel config: https://syzkaller.appspot.com/x/.config?x=cd456c5e6582895e dashboard link: https://syzkaller.appspot.com/bug?extid=c71bc336c5061153b502 compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=167ac787680000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1799f190e80000 Downloadable assets: disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-d2f51b35.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/d678011e498e/vmlinux-d2f51b35.xz kernel image: https://storage.googleapis.com/syzbot-assets/4f6ed772923d/bzImage-d2f51b35.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+c71bc336c5061153b502@xxxxxxxxxxxxxxxxxxxxxxxxx general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 3 PID: 5345 Comm: syz-executor785 Not tainted 6.6.0-syzkaller-14651-gd2f51b3516da #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 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 5f cd f7 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:ffffc90003797870 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffff88802a2bd000 RSI: ffffffff89ba330e RDI: ffff88802d7d9540 RBP: ffff88802d7d9540 R08: 0000000000000001 R09: fffffbfff23e11e9 R10: ffffffff91f08f4f R11: ffffffff915e5030 R12: ffff8880186c9cc0 R13: dffffc0000000000 R14: ffffed1005afb3c7 R15: ffff88802d7d9e38 FS: 00007f263ceef6c0(0000) GS:ffff88806b900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020002980 CR3: 000000001b2ab000 CR4: 0000000000350ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> 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:2588 ___sys_sendmsg+0x135/0x1d0 net/socket.c:2642 __sys_sendmmsg+0x1a1/0x450 net/socket.c:2728 __do_sys_sendmmsg net/socket.c:2757 [inline] __se_sys_sendmmsg net/socket.c:2754 [inline] __x64_sys_sendmmsg+0x9c/0x100 net/socket.c:2754 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3f/0x110 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x63/0x6b RIP: 0033:0x7f263cf53559 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 61 1a 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:00007f263ceef218 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007f263cfdd438 RCX: 00007f263cf53559 RDX: 0400000000000239 RSI: 0000000020002980 RDI: 0000000000000006 RBP: 00007f263cfdd430 R08: 00007fff5b335167 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f263cfdd43c R13: 00007f263cfaa504 R14: 0400000000000239 R15: 00007fff5b335168 </TASK> 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 5f cd f7 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:ffffc90003797870 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffff88802a2bd000 RSI: ffffffff89ba330e RDI: ffff88802d7d9540 RBP: ffff88802d7d9540 R08: 0000000000000001 R09: fffffbfff23e11e9 R10: ffffffff91f08f4f R11: ffffffff915e5030 R12: ffff8880186c9cc0 R13: dffffc0000000000 R14: ffffed1005afb3c7 R15: ffff88802d7d9e38 FS: 00007f263ceef6c0(0000) GS:ffff88806b900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020002980 CR3: 000000001b2ab000 CR4: 0000000000350ef0 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 5f cd f7 call 0xf7cd5f94 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 --- If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing.
