On Fri, Sep 27, 2024 at 10:59 AM syzbot <syzbot+f4e0f821e3a3b7cee51d@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > Hello, > > syzbot found the following issue on: > > HEAD commit: 196145c606d0 Merge tag 'clk-fixes-for-linus' of git://git... > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=16f8549f980000 > kernel config: https://syzkaller.appspot.com/x/.config?x=61d235cb8d15001c > dashboard link: https://syzkaller.appspot.com/bug?extid=f4e0f821e3a3b7cee51d > compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 > userspace arch: i386 > > Unfortunately, I don't have any reproducer for this issue yet. > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/629d679a6d66/disk-196145c6.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/aec0dd4a04f3/vmlinux-196145c6.xz > kernel image: https://storage.googleapis.com/syzbot-assets/68e515733997/bzImage-196145c6.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+f4e0f821e3a3b7cee51d@xxxxxxxxxxxxxxxxxxxxxxxxx > > Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN PTI > KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] > CPU: 1 UID: 0 PID: 10078 Comm: syz.4.940 Not tainted 6.11.0-rc7-syzkaller-00097-g196145c606d0 #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024 > RIP: 0010:sctp_inet_listen+0x7f0/0xa20 net/sctp/socket.c:8617 In sctp_listen_start() invoked by sctp_inet_listen(), it should set the socket state back to CLOSED if sctp_autobind() fails due to whatever reason: @@ -8557,8 +8557,10 @@ static int sctp_listen_start(struct sock *sk, int backlog) */ inet_sk_set_state(sk, SCTP_SS_LISTENING); if (!ep->base.bind_addr.port) { - if (sctp_autobind(sk)) + if (sctp_autobind(sk)) { + inet_sk_set_state(sk, SCTP_SS_CLOSED); return -EAGAIN; + } Otherwise, next time when calling sctp_inet_listen(), if sctp_sk(sk)->reuse is already set via setsockopt(SCTP_REUSE_PORT), sctp_sk(sk)->bind_hash will be dereferenced as the state is LISTENING, and causes crash as bind_hash is NULL. > Code: 8d 98 00 06 00 00 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 6e 4e 05 f7 48 8b 1b 48 83 c3 02 48 89 d8 48 c1 e8 03 <42> 0f b6 04 28 84 c0 0f 85 8e 01 00 00 c6 03 01 31 db e9 d6 f9 ff > RSP: 0018:ffffc90002eafd20 EFLAGS: 00010246 > RAX: 0000000000000000 RBX: 0000000000000002 RCX: ffff88802e973c00 > RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 > RBP: ffffc90002eafe78 R08: ffffffff8af5839c R09: 1ffffffff283c920 > R10: dffffc0000000000 R11: fffffbfff283c921 R12: 1ffff1100fc7e242 > R13: dffffc0000000000 R14: ffff88807e3f1212 R15: 1ffff1100fc7e2ff > FS: 0000000000000000(0000) GS:ffff8880b8900000(0063) knlGS:00000000f5735b40 > CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 > CR2: 00007fadae30cff8 CR3: 0000000050d9a000 CR4: 00000000003506f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > <TASK> > __sys_listen_socket net/socket.c:1883 [inline] > __sys_listen+0x1b7/0x230 net/socket.c:1894 > __do_sys_listen net/socket.c:1902 [inline] > __se_sys_listen net/socket.c:1900 [inline] > __ia32_sys_listen+0x5a/0x70 net/socket.c:1900 > do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] > __do_fast_syscall_32+0xb4/0x110 arch/x86/entry/common.c:386 > do_fast_syscall_32+0x34/0x80 arch/x86/entry/common.c:411 > entry_SYSENTER_compat_after_hwframe+0x84/0x8e > RIP: 0023:0xf7fd6579 > Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 > RSP: 002b:00000000f573556c EFLAGS: 00000206 ORIG_RAX: 000000000000016b > RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000000000 > RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 > RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 > R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 > </TASK> > Modules linked in: > ---[ end trace 0000000000000000 ]--- > RIP: 0010:sctp_inet_listen+0x7f0/0xa20 net/sctp/socket.c:8617 > Code: 8d 98 00 06 00 00 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 6e 4e 05 f7 48 8b 1b 48 83 c3 02 48 89 d8 48 c1 e8 03 <42> 0f b6 04 28 84 c0 0f 85 8e 01 00 00 c6 03 01 31 db e9 d6 f9 ff > RSP: 0018:ffffc90002eafd20 EFLAGS: 00010246 > RAX: 0000000000000000 RBX: 0000000000000002 RCX: ffff88802e973c00 > RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 > RBP: ffffc90002eafe78 R08: ffffffff8af5839c R09: 1ffffffff283c920 > R10: dffffc0000000000 R11: fffffbfff283c921 R12: 1ffff1100fc7e242 > R13: dffffc0000000000 R14: ffff88807e3f1212 R15: 1ffff1100fc7e2ff > FS: 0000000000000000(0000) GS:ffff8880b8900000(0063) knlGS:00000000f5735b40 > CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 > CR2: 000055f65cf85950 CR3: 0000000050d9a000 CR4: 00000000003506f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > ---------------- > Code disassembly (best guess): > 0: 8d 98 00 06 00 00 lea 0x600(%rax),%ebx > 6: 48 89 d8 mov %rbx,%rax > 9: 48 c1 e8 03 shr $0x3,%rax > d: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1) > 12: 74 08 je 0x1c > 14: 48 89 df mov %rbx,%rdi > 17: e8 6e 4e 05 f7 call 0xf7054e8a > 1c: 48 8b 1b mov (%rbx),%rbx > 1f: 48 83 c3 02 add $0x2,%rbx > 23: 48 89 d8 mov %rbx,%rax > 26: 48 c1 e8 03 shr $0x3,%rax > * 2a: 42 0f b6 04 28 movzbl (%rax,%r13,1),%eax <-- trapping instruction > 2f: 84 c0 test %al,%al > 31: 0f 85 8e 01 00 00 jne 0x1c5 > 37: c6 03 01 movb $0x1,(%rbx) > 3a: 31 db xor %ebx,%ebx > 3c: e9 .byte 0xe9 > 3d: d6 (bad) > 3e: f9 stc > 3f: ff .byte 0xff > > > --- > This report is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. > > syzbot will keep track of this issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > If the report is already addressed, let syzbot know by replying with: > #syz fix: exact-commit-title > > If you want to overwrite report's subsystems, reply with: > #syz set subsystems: new-subsystem > (See the list of subsystem names on the web dashboard) > > If the report is a duplicate of another one, reply with: > #syz dup: exact-subject-of-another-report > > If you want to undo deduplication, reply with: > #syz undup
