[syzbot] [sctp?] general protection fault in sctp_outq_tail

syzbot
2023-03-23T00:40:00Z

Hello,

syzbot found the following issue on:

HEAD commit: cdd28833100c net: microchip: sparx5: fix deletion of exist..
git tree: net
console output: https://syzkaller.appspot.com/x/log.txt?x=1588fe92c80000
kernel config: https://syzkaller.appspot.com/x/.config?x=cab35c936731a347
dashboard link: https://syzkaller.appspot.com/bug?extid=47c24ca20a2fa01f082e
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15d80ff4c80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17f6e90ac80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/2fb6257d1131/disk-cdd28833.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a3025d79117c/vmlinux-cdd28833.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8e6d670a5fed/bzImage-cdd28833.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+47c24ca20a2fa01f082e@syzkaller.appspotmail.com

general protection fault, probably for non-canonical address 0xdffffc0000000007: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000038-0x000000000000003f]
CPU: 1 PID: 5783 Comm: syz-executor825 Not tainted 6.2.0-syzkaller-12889-gcdd28833100c #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
RIP: 0010:list_add_tail include/linux/list.h:102 [inline]
RIP: 0010:sctp_outq_tail_data net/sctp/outqueue.c:91 [inline]
RIP: 0010:sctp_outq_tail+0x4ab/0xbf0 net/sctp/outqueue.c:299
Code: 8b 48 08 4c 8d 6b 18 48 8d 41 30 48 89 44 24 08 48 8d 41 38 48 89 c2 48 89 44 24 20 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f 85 0a 06 00 00 4c 8b 79 38 4c 89 ef 48 89 4c 24 28
RSP: 0018:ffffc90005257568 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff888072779140 RCX: 0000000000000000
RDX: 0000000000000007 RSI: ffffffff841d7ef0 RDI: ffff888071fbb0c8
RBP: ffff8880787a47e0 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff92000a4aeb3
R13: ffff888072779158 R14: ffff8880787c0000 R15: ffff888071ad7c80
FS: 00007f5801104700(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f58011b0740 CR3: 000000002a37e000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
sctp_cmd_send_msg net/sctp/sm_sideeffect.c:1114 [inline]
sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1777 [inline]
sctp_side_effects net/sctp/sm_sideeffect.c:1199 [inline]
sctp_do_sm+0x197d/0x5310 net/sctp/sm_sideeffect.c:1170
sctp_primitive_SEND+0x9f/0xc0 net/sctp/primitive.c:163
sctp_sendmsg_to_asoc+0x10eb/0x1a30 net/sctp/socket.c:1868
sctp_sendmsg+0x8d4/0x1d90 net/sctp/socket.c:2026
inet_sendmsg+0x9d/0xe0 net/ipv4/af_inet.c:825
sock_sendmsg_nosec net/socket.c:722 [inline]
sock_sendmsg+0xde/0x190 net/socket.c:745
__sys_sendto+0x23a/0x340 net/socket.c:2145
__do_sys_sendto net/socket.c:2157 [inline]
__se_sys_sendto net/socket.c:2153 [inline]
__x64_sys_sendto+0xe1/0x1b0 net/socket.c:2153
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f5801177ce9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 15 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f58011042f8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f58012004b8 RCX: 00007f5801177ce9
RDX: 0000000000034000 RSI: 0000000020000080 RDI: 0000000000000003
RBP: 00007f58012004b0 R08: 00000000200005c0 R09: 000000000000001c
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f58012004bc
R13: 00007f58011cd600 R14: 0100000000000000 R15: 0000000000022000
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:list_add_tail include/linux/list.h:102 [inline]
RIP: 0010:sctp_outq_tail_data net/sctp/outqueue.c:91 [inline]
RIP: 0010:sctp_outq_tail+0x4ab/0xbf0 net/sctp/outqueue.c:299
Code: 8b 48 08 4c 8d 6b 18 48 8d 41 30 48 89 44 24 08 48 8d 41 38 48 89 c2 48 89 44 24 20 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f 85 0a 06 00 00 4c 8b 79 38 4c 89 ef 48 89 4c 24 28
RSP: 0018:ffffc90005257568 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff888072779140 RCX: 0000000000000000
RDX: 0000000000000007 RSI: ffffffff841d7ef0 RDI: ffff888071fbb0c8
RBP: ffff8880787a47e0 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff92000a4aeb3
R13: ffff888072779158 R14: ffff8880787c0000 R15: ffff888071ad7c80
FS: 00007f5801104700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd458c9960 CR3: 000000002a37e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 8b 48 08 mov 0x8(%rax),%ecx
3: 4c 8d 6b 18 lea 0x18(%rbx),%r13
7: 48 8d 41 30 lea 0x30(%rcx),%rax
b: 48 89 44 24 08 mov %rax,0x8(%rsp)
10: 48 8d 41 38 lea 0x38(%rcx),%rax
14: 48 89 c2 mov %rax,%rdx
17: 48 89 44 24 20 mov %rax,0x20(%rsp)
1c: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
23: fc ff df
26: 48 c1 ea 03 shr $0x3,%rdx
* 2a: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction
2e: 0f 85 0a 06 00 00 jne 0x63e
34: 4c 8b 79 38 mov 0x38(%rcx),%r15
38: 4c 89 ef mov %r13,%rdi
3b: 48 89 4c 24 28 mov %rcx,0x28(%rsp)

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