kernel BUG at net/rxrpc/conn_object.c:LINE!

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: f5499c67 nfc: pn533/usb.c: fix spelling of "functions"
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=16415055900000
kernel config: https://syzkaller.appspot.com/x/.config?x=2b946b3cd0adc99
dashboard link: https://syzkaller.appspot.com/bug?extid=52071f826a617b9c76ed
compiler: gcc (GCC) 10.1.0-syz 20200507
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16be260d900000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=100b7cdd900000

The issue was bisected to:

commit 245500d853e9f20036cec7df4f6984ece4c6bf26
Author: David Howells <dhow...@redhat.com>
Date: Wed Jul 1 10:15:32 2020 +0000

rxrpc: Rewrite the client connection manager

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=11950759900000
final oops: https://syzkaller.appspot.com/x/report.txt?x=13950759900000
console output: https://syzkaller.appspot.com/x/log.txt?x=15950759900000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+52071f...@syzkaller.appspotmail.com
Fixes: 245500d853e9 ("rxrpc: Rewrite the client connection manager")

rxrpc: Assertion failed
------------[ cut here ]------------
kernel BUG at net/rxrpc/conn_object.c:481!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 234 Comm: kworker/u4:5 Not tainted 5.9.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
RIP: 0010:rxrpc_destroy_all_connections.cold+0x11/0x13 net/rxrpc/conn_object.c:481
Code: c0 48 c7 c1 00 b0 14 89 48 89 f2 48 c7 c7 80 ac 14 89 e8 04 4d 0c fa 0f 0b e8 be 15 23 fa 48 c7 c7 80 af 14 89 e8 f1 4c 0c fa <0f> 0b 41 57 41 56 41 55 41 54 55 53 48 89 f3 48 83 ec 20 48 89 3c
RSP: 0018:ffffc90000f57b18 EFLAGS: 00010282
RAX: 0000000000000017 RBX: ffff8880945a8000 RCX: 0000000000000000
RDX: ffff8880a85ca200 RSI: ffffffff815dbd97 RDI: fffff520001eaf55
RBP: ffff8880945a8064 R08: 0000000000000017 R09: ffff8880ae731927
R10: 0000000000000000 R11: 0000000034333254 R12: ffff8880945a8068
R13: ffff8880945a8078 R14: ffff8880945a8078 R15: ffff8880945a7eb8
FS: 0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fdbae898020 CR3: 00000000963ae000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
rxrpc_exit_net+0x1a4/0x2e0 net/rxrpc/net_ns.c:119
ops_exit_list+0xb0/0x160 net/core/net_namespace.c:186
cleanup_net+0x4ea/0xa00 net/core/net_namespace.c:603
process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
kthread+0x3b5/0x4a0 kernel/kthread.c:292
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
Modules linked in:
---[ end trace b82f4cc98146655f ]---
RIP: 0010:rxrpc_destroy_all_connections.cold+0x11/0x13 net/rxrpc/conn_object.c:481
Code: c0 48 c7 c1 00 b0 14 89 48 89 f2 48 c7 c7 80 ac 14 89 e8 04 4d 0c fa 0f 0b e8 be 15 23 fa 48 c7 c7 80 af 14 89 e8 f1 4c 0c fa <0f> 0b 41 57 41 56 41 55 41 54 55 53 48 89 f3 48 83 ec 20 48 89 3c
RSP: 0018:ffffc90000f57b18 EFLAGS: 00010282
RAX: 0000000000000017 RBX: ffff8880945a8000 RCX: 0000000000000000
RDX: ffff8880a85ca200 RSI: ffffffff815dbd97 RDI: fffff520001eaf55
RBP: ffff8880945a8064 R08: 0000000000000017 R09: ffff8880ae731927
R10: 0000000000000000 R11: 0000000034333254 R12: ffff8880945a8068
R13: ffff8880945a8078 R14: ffff8880945a8078 R15: ffff8880945a7eb8
FS: 0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fdbae89e000 CR3: 0000000093fd8000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


---
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[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+52071f...@syzkaller.appspotmail.com

Tested on:

commit: 6b02addb Add linux-next specific files for 20200915
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
kernel config: https://syzkaller.appspot.com/x/.config?x=9b13f25766f2cb5d

dashboard link: https://syzkaller.appspot.com/bug?extid=52071f826a617b9c76ed
compiler: gcc (GCC) 10.1.0-syz 20200507

Note: testing is done by a robot and is best-effort only.