general protection fault in hfsc_unbind_tcf

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: a083db76 Linux 4.19.107
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=162614e3e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=c32f76aaadd644de
dashboard link: https://syzkaller.appspot.com/bug?extid=6d6c1d4a07addd085720
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

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

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+6d6c1d...@syzkaller.appspotmail.com

device veth0_macvtap left promiscuous mode
device veth1_vlan left promiscuous mode
device veth0_vlan left promiscuous mode
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: 23 Comm: kworker/u4:1 Not tainted 4.19.107-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
RIP: 0010:hfsc_unbind_tcf+0x1e/0x40 net/sched/sch_hfsc.c:1247
Code: fb eb af e8 b4 56 e5 fb eb de 66 90 53 48 89 f3 e8 07 90 af fb 48 8d 7b 50 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 04 3c 03 7e 06 83 6b 50 01 5b c3 e8 6b 56 e5
RSP: 0018:ffff8880a949f638 EFLAGS: 00010a06
RAX: dffffc0000000000 RBX: dead4ead00000000 RCX: ffffffff85c1e7d2
RDX: 1bd5a9d5a000000a RSI: ffffffff85b808b9 RDI: dead4ead00000050
RBP: ffff88808fdb1f00 R08: ffff8880a948c600 R09: ffffed1011fb63e3
R10: ffffed1011fb63e2 R11: ffff88808fdb1f17 R12: dead4ead00000000
R13: ffff88803f93a380 R14: dffffc0000000000 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000c41010 CR3: 000000009070f000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
__tcf_unbind_filter include/net/pkt_cls.h:241 [inline]
tcf_unbind_filter include/net/pkt_cls.h:251 [inline]
route4_destroy+0x35f/0x7e0 net/sched/cls_route.c:300
tcf_proto_destroy+0x5d/0xe0 net/sched/cls_api.c:190
tcf_chain_flush+0x1ed/0x330 net/sched/cls_api.c:362
tcf_block_put_ext.part.0+0x418/0x9a0 net/sched/cls_api.c:770
tcf_block_put_ext net/sched/cls_api.c:754 [inline]
tcf_block_put+0xad/0xf8 net/sched/cls_api.c:797
hfsc_destroy_qdisc+0xe0/0x280 net/sched/sch_hfsc.c:1509
qdisc_destroy+0x17c/0x6b0 net/sched/sch_generic.c:982
dev_shutdown+0x2b5/0x47a net/sched/sch_generic.c:1300
rollback_registered_many+0x64a/0xc40 net/core/dev.c:8173
unregister_netdevice_many.part.0+0x16/0x1e0 net/core/dev.c:9294
unregister_netdevice_many net/core/dev.c:9293 [inline]
default_device_exit_batch+0x2ff/0x3c0 net/core/dev.c:9765
ops_exit_list.isra.0+0xef/0x140 net/core/net_namespace.c:156
cleanup_net+0x3bf/0x850 net/core/net_namespace.c:553
process_one_work+0x91f/0x1640 kernel/workqueue.c:2153
worker_thread+0x96/0xe20 kernel/workqueue.c:2296
kthread+0x34a/0x420 kernel/kthread.c:246
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
Modules linked in:
---[ end trace e93c383e1ef74bfa ]---
RIP: 0010:hfsc_unbind_tcf+0x1e/0x40 net/sched/sch_hfsc.c:1247
Code: fb eb af e8 b4 56 e5 fb eb de 66 90 53 48 89 f3 e8 07 90 af fb 48 8d 7b 50 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 04 3c 03 7e 06 83 6b 50 01 5b c3 e8 6b 56 e5
RSP: 0018:ffff8880a949f638 EFLAGS: 00010a06
RAX: dffffc0000000000 RBX: dead4ead00000000 RCX: ffffffff85c1e7d2
RDX: 1bd5a9d5a000000a RSI: ffffffff85b808b9 RDI: dead4ead00000050
RBP: ffff88808fdb1f00 R08: ffff8880a948c600 R09: ffffed1011fb63e3
R10: ffffed1011fb63e2 R11: ffff88808fdb1f17 R12: dead4ead00000000
R13: ffff88803f93a380 R14: dffffc0000000000 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000370f5680 CR3: 0000000093d1f000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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[syzbot]

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