bisecting fixing commit since c076c79e03c6094e578df5d210fde808b3ad32e6
building syzkaller on 0487ea6f5d997a8363eba0d2eb0ea7a925444555
testing commit c076c79e03c6094e578df5d210fde808b3ad32e6 with gcc (GCC) 8.4.1 20210217
kernel signature: b28536a3d197716fe42453993cfc5fc13abba229850f3b50c44a3f2c9af7f6f1
all runs: crashed: BUG: corrupted list in l2cap_chan_put
testing current HEAD 255b58a2b3af0baa0ee11507390349217b8b73b0
testing commit 255b58a2b3af0baa0ee11507390349217b8b73b0 with gcc (GCC) 8.4.1 20210217
kernel signature: f5640bd32d269019267de8bd6f53f9b5af6b8cc26cc52fd04dd0884d1a7fd194
all runs: crashed: BUG: corrupted list in l2cap_chan_put
revisions tested: 2, total time: 34m14.645497821s (build: 15m29.78566564s, test: 17m46.420711116s)
the crash still happens on HEAD
commit msg: Linux 4.19.176
crash: BUG: corrupted list in l2cap_chan_put
bond0 (unregistering): Releasing backup interface bond_slave_0
bond0 (unregistering): Released all slaves
IPVS: ftp: loaded support on port[0] = 21
list_del corruption, ffff8881d627c5c8->next is LIST_POISON1 (dead000000000100)
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:47!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 25545 Comm: kworker/u5:0 Not tainted 4.19.176-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: hci0 hci_rx_work
RIP: 0010:__list_del_entry_valid.cold.1+0x26/0x4a lib/list_debug.c:45
Code: f9 ff 0f 0b 4c 89 e2 48 89 de 48 c7 c7 c0 89 67 87 e8 0a 6d f9 ff 0f 0b 4c 89 ea 48 89 de 48 c7 c7 60 89 67 87 e8 f6 6c f9 ff <0f> 0b 48 89 de 48 c7 c7 80 8a 67 87 e8 e5 6c f9 ff 0f 0b 48 89 de
RSP: 0018:ffff8881d5af76f8 EFLAGS: 00010282
RAX: 000000000000004e RBX: ffff8881d627c5c8 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff876786c0 RDI: ffffffff8a19eaa0
RBP: ffff8881d5af7710 R08: ffffed103ed25081 R09: ffffed103ed25080
R10: ffffed103ed25080 R11: ffff8881f6928407 R12: dead000000000200
R13: dead000000000100 R14: ffff8881e0b34340 R15: ffff8881e0b343c0
FS:  0000000000000000(0000) GS:ffff8881f6900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000007ac608 CR3: 000000000846d001 CR4: 00000000001606e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __list_del_entry include/linux/list.h:117 [inline]
 list_del include/linux/list.h:125 [inline]
 l2cap_chan_destroy net/bluetooth/l2cap_core.c:479 [inline]
 kref_put include/linux/kref.h:70 [inline]
 l2cap_chan_put+0x49/0x1a0 net/bluetooth/l2cap_core.c:496
 l2cap_conless_channel net/bluetooth/l2cap_core.c:6982 [inline]
 l2cap_recv_frame+0xf29/0xa430 net/bluetooth/l2cap_core.c:7029
 l2cap_recv_acldata+0x756/0x8a0 net/bluetooth/l2cap_core.c:7594
 hci_acldata_packet net/bluetooth/hci_core.c:4178 [inline]
 hci_rx_work+0x5d6/0x8f0 net/bluetooth/hci_core.c:4364
 process_one_work+0x7b9/0x15a0 kernel/workqueue.c:2152
 worker_thread+0x85/0xb60 kernel/workqueue.c:2295
 kthread+0x347/0x410 kernel/kthread.c:259
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
Modules linked in:
---[ end trace aacd3e54d6923e0e ]---
RIP: 0010:__list_del_entry_valid.cold.1+0x26/0x4a lib/list_debug.c:45
Code: f9 ff 0f 0b 4c 89 e2 48 89 de 48 c7 c7 c0 89 67 87 e8 0a 6d f9 ff 0f 0b 4c 89 ea 48 89 de 48 c7 c7 60 89 67 87 e8 f6 6c f9 ff <0f> 0b 48 89 de 48 c7 c7 80 8a 67 87 e8 e5 6c f9 ff 0f 0b 48 89 de
RSP: 0018:ffff8881d5af76f8 EFLAGS: 00010282
RAX: 000000000000004e RBX: ffff8881d627c5c8 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff876786c0 RDI: ffffffff8a19eaa0
RBP: ffff8881d5af7710 R08: ffffed103ed25081 R09: ffffed103ed25080
R10: ffffed103ed25080 R11: ffff8881f6928407 R12: dead000000000200
R13: dead000000000100 R14: ffff8881e0b34340 R15: ffff8881e0b343c0
FS:  0000000000000000(0000) GS:ffff8881f6900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000007ac608 CR3: 000000000846d001 CR4: 00000000001606e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400