bisecting fixing commit since c076c79e03c6094e578df5d210fde808b3ad32e6
building syzkaller on 4ca1c0ea446d2c09b1fb49a85ae645e3754f1058
testing commit c076c79e03c6094e578df5d210fde808b3ad32e6 with gcc (GCC) 8.4.1 20210217
kernel signature: 8d0d49b4fb97e2ad9667e23a3909071b45e71c71e66d02c7e5de92f116accc7c
all runs: crashed: BUG: corrupted list in l2cap_chan_put
testing current HEAD 125222814e7b8f84df767d6ab622aff2a6d2f234
testing commit 125222814e7b8f84df767d6ab622aff2a6d2f234 with gcc (GCC) 8.4.1 20210217
kernel signature: f14b5b199aae57759d259ff9d2fe0cfd8ae4698064a7d010fe2b81ec1cfab135
all runs: crashed: BUG: corrupted list in l2cap_chan_put
revisions tested: 2, total time: 35m40.339081699s (build: 16m38.37632124s, test: 18m38.294712589s)
the crash still happens on HEAD
commit msg: Linux 4.19.182
crash: BUG: corrupted list in l2cap_chan_put
Bluetooth: hci5: command 0x0419 tx timeout
Bluetooth: hci4: command 0x0419 tx timeout
Bluetooth: hci3: command 0x0419 tx timeout
list_del corruption, ffff8881ce1aa788->next is LIST_POISON1 (dead000000000100)
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:47!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 2212 Comm: kworker/u5:2 Not tainted 4.19.182-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 8c 67 87 e8 9b 6c f9 ff 0f 0b 4c 89 ea 48 89 de 48 c7 c7 60 8c 67 87 e8 87 6c f9 ff <0f> 0b 48 89 de 48 c7 c7 80 8d 67 87 e8 76 6c f9 ff 0f 0b 48 89 de
RSP: 0018:ffff8881ddc8f6f8 EFLAGS: 00010282
RAX: 000000000000004e RBX: ffff8881ce1aa788 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff876789c0 RDI: ffffffff8a19faa0
RBP: ffff8881ddc8f710 R08: ffffed103ed05081 R09: ffffed103ed05080
R10: ffffed103ed05080 R11: ffff8881f6828407 R12: dead000000000200
R13: dead000000000100 R14: ffff8881d39be080 R15: ffff8881d39be100
FS:  0000000000000000(0000) GS:ffff8881f6800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000130f608 CR3: 000000000846d006 CR4: 00000000001606f0
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:4180 [inline]
 hci_rx_work+0x5d6/0x8f0 net/bluetooth/hci_core.c:4366
 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 49dbf8202deec8bc ]---
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 8c 67 87 e8 9b 6c f9 ff 0f 0b 4c 89 ea 48 89 de 48 c7 c7 60 8c 67 87 e8 87 6c f9 ff <0f> 0b 48 89 de 48 c7 c7 80 8d 67 87 e8 76 6c f9 ff 0f 0b 48 89 de
RSP: 0018:ffff8881ddc8f6f8 EFLAGS: 00010282
RAX: 000000000000004e RBX: ffff8881ce1aa788 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff876789c0 RDI: ffffffff8a19faa0
RBP: ffff8881ddc8f710 R08: ffffed103ed05081 R09: ffffed103ed05080
R10: ffffed103ed05080 R11: ffff8881f6828407 R12: dead000000000200
R13: dead000000000100 R14: ffff8881d39be080 R15: ffff8881d39be100
FS:  0000000000000000(0000) GS:ffff8881f6800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000130f608 CR3: 000000000846d006 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400