general protection fault in sctp_sched_fcfs_dequeue

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3f8a27f9e27b Linux 4.19.211
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=10265e2bb00000
kernel config: https://syzkaller.appspot.com/x/.config?x=9b9277b418617afe
dashboard link: https://syzkaller.appspot.com/bug?extid=2e7ff2b0892192ae5a65
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2e7ff2...@syzkaller.appspotmail.com

kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 31353 Comm: syz-executor.3 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:sctp_sched_fcfs_dequeue+0xc9/0x140 net/sctp/stream_sched.c:83
Code: 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 80 00 00 00 48 b8 00 00 00 00 00 fc ff df 49 8b 5c 24 08 48 8d 7b 30 48 89 fa 48 c1 ea 03 <80> 3c 02 00 75 59 4c 8b 63 30 49 83 ec 18 e8 d4 74 eb f9 4c 89 e6
RSP: 0018:ffff8882351978c8 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 00000000a8918f80 RCX: ffffffff876f97a6
RDX: 00000000151231f6 RSI: ffffffff8777104f RDI: 00000000a8918fb0
RBP: ffff888000134a28 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff8880001202d8
R13: ffffed1000026948 R14: ffff888000134a4c R15: 1ffff11000026949
FS: 000055555716f400(0000) GS:ffff8880ba000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555555bdb8c8 CR3: 00000000a6a9a000 CR4: 00000000003406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
sctp_outq_dequeue_data net/sctp/outqueue.c:91 [inline]
__sctp_outq_teardown+0x729/0xc20 net/sctp/outqueue.c:267
sctp_association_free+0x212/0x7b0 net/sctp/associola.c:361
sctp_cmd_delete_tcb net/sctp/sm_sideeffect.c:944 [inline]
sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1332 [inline]
sctp_side_effects net/sctp/sm_sideeffect.c:1199 [inline]
sctp_do_sm+0x39ee/0x5110 net/sctp/sm_sideeffect.c:1170
sctp_primitive_SHUTDOWN+0x9b/0xc0 net/sctp/primitive.c:104
sctp_close+0x3d9/0x7f0 net/sctp/socket.c:1574
inet_release+0xd7/0x1e0 net/ipv4/af_inet.c:427
__sock_release+0xcd/0x2a0 net/socket.c:599
sock_close+0x15/0x20 net/socket.c:1214
__fput+0x2ce/0x890 fs/file_table.c:278
task_work_run+0x148/0x1c0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:193 [inline]
exit_to_usermode_loop+0x251/0x2a0 arch/x86/entry/common.c:167
prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
syscall_return_slowpath arch/x86/entry/common.c:271 [inline]
do_syscall_64+0x538/0x620 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f48cca8aadb
Code: 0f 05 48 3d 00 f0 ff ff 77 45 c3 0f 1f 40 00 48 83 ec 18 89 7c 24 0c e8 63 fc ff ff 8b 7c 24 0c 41 89 c0 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 44 89 c7 89 44 24 0c e8 a1 fc ff ff 8b 44
RSP: 002b:00007ffc9fd269c0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000006 RCX: 00007f48cca8aadb
RDX: 0000001b2f920000 RSI: 00007f48cc98da98 RDI: 0000000000000005
RBP: 00007f48ccbec960 R08: 0000000000000000 R09: 000000003253460c
R10: 001cf26554f24b33 R11: 0000000000000293 R12: 00000000000eadb2
R13: 00007ffc9fd26ac0 R14: 00007f48ccbeb030 R15: 0000000000000032
Modules linked in:
---[ end trace b384dfd7fe3b1f52 ]---
RIP: 0010:sctp_sched_fcfs_dequeue+0xc9/0x140 net/sctp/stream_sched.c:83
Code: 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 80 00 00 00 48 b8 00 00 00 00 00 fc ff df 49 8b 5c 24 08 48 8d 7b 30 48 89 fa 48 c1 ea 03 <80> 3c 02 00 75 59 4c 8b 63 30 49 83 ec 18 e8 d4 74 eb f9 4c 89 e6
RSP: 0018:ffff8882351978c8 EFLAGS: 00010206
overlayfs: failed to resolve './file1': -2
RAX: dffffc0000000000 RBX: 00000000a8918f80 RCX: ffffffff876f97a6
RDX: 00000000151231f6 RSI: ffffffff8777104f RDI: 00000000a8918fb0
RBP: ffff888000134a28 R08: 0000000000000000 R09: 0000000000000000
overlayfs: missing 'lowerdir'
R10: 0000000000000001 R11: 0000000000000000 R12: ffff8880001202d8
R13: ffffed1000026948 R14: ffff888000134a4c R15: 1ffff11000026949
FS: 000055555716f400(0000) GS:ffff8880ba000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000205dd000 CR3: 00000000a6a9a000 CR4: 00000000003406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 89 fa mov %edi,%edx
2: 48 c1 ea 03 shr $0x3,%rdx
6: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1)
a: 0f 85 80 00 00 00 jne 0x90
10: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
17: fc ff df
1a: 49 8b 5c 24 08 mov 0x8(%r12),%rbx
1f: 48 8d 7b 30 lea 0x30(%rbx),%rdi
23: 48 89 fa mov %rdi,%rdx
26: 48 c1 ea 03 shr $0x3,%rdx
* 2a: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction
2e: 75 59 jne 0x89
30: 4c 8b 63 30 mov 0x30(%rbx),%r12
34: 49 83 ec 18 sub $0x18,%r12
38: e8 d4 74 eb f9 callq 0xf9eb7511
3d: 4c 89 e6 mov %r12,%rsi


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.