bisecting fixing commit since c076c79e03c6094e578df5d210fde808b3ad32e6 building syzkaller on 4ca1c0ea446d2c09b1fb49a85ae645e3754f1058 testing commit c076c79e03c6094e578df5d210fde808b3ad32e6 with gcc (GCC) 8.1.0 kernel signature: c6a4581d932122df1d3c818d4d930669933e71a5328ba006f25db4579ce1daf0 all runs: crashed: BUG: corrupted list in l2cap_chan_put testing current HEAD daefdc9eb24bfa11ab77a4b2a9c3923f1051fe0b testing commit daefdc9eb24bfa11ab77a4b2a9c3923f1051fe0b with gcc (GCC) 8.1.0 kernel signature: ee1f9072fdd6f7045cb22a240ba230537c67be5de4770564c195cae28dee40bd all runs: crashed: BUG: corrupted list in l2cap_chan_put revisions tested: 2, total time: 34m47.884069605s (build: 19m20.595195996s, test: 14m54.865151558s) the crash still happens on HEAD commit msg: Linux 4.19.161 crash: BUG: corrupted list in l2cap_chan_put Bluetooth: hci3: command 0x0419 tx timeout Bluetooth: hci4: command 0x0419 tx timeout Bluetooth: hci5: command 0x0419 tx timeout list_del corruption, ffff8881f2c27888->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: 31806 Comm: kworker/u5:4 Not tainted 4.19.161-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: hci3 hci_rx_work RIP: 0010:__list_del_entry_valid.cold.1+0x26/0x58 lib/list_debug.c:45 Code: 1d fe 0f 0b 4c 89 e2 48 89 de 48 c7 c7 60 88 67 87 e8 76 6d 1d fe 0f 0b 4c 89 ea 48 89 de 48 c7 c7 00 88 67 87 e8 62 6d 1d fe <0f> 0b 48 89 de 48 c7 c7 20 89 67 87 e8 51 6d 1d fe 0f 0b 48 89 de RSP: 0018:ffff8881ddfbf6f8 EFLAGS: 00010282 RAX: 000000000000004e RBX: ffff8881f2c27888 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff87678560 RDI: ffffffff8a19ca60 RBP: ffff8881ddfbf710 R08: ffffed103ed25081 R09: ffffed103ed25080 R10: ffffed103ed25080 R11: ffff8881f6928407 R12: dead000000000200 R13: dead000000000100 R14: ffff8881c62ed300 R15: ffff8881c62ed380 FS: 0000000000000000(0000) GS:ffff8881f6900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000004d04d0 CR3: 000000000846d003 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+0xf29/0xa440 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+0x5e1/0x8e0 net/bluetooth/hci_core.c:4364 process_one_work+0x7b9/0x15a0 kernel/workqueue.c:2155 worker_thread+0x85/0xb60 kernel/workqueue.c:2298 kthread+0x347/0x410 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Modules linked in: ---[ end trace e089c0ddba2b5a24 ]--- RIP: 0010:__list_del_entry_valid.cold.1+0x26/0x58 lib/list_debug.c:45 Code: 1d fe 0f 0b 4c 89 e2 48 89 de 48 c7 c7 60 88 67 87 e8 76 6d 1d fe 0f 0b 4c 89 ea 48 89 de 48 c7 c7 00 88 67 87 e8 62 6d 1d fe <0f> 0b 48 89 de 48 c7 c7 20 89 67 87 e8 51 6d 1d fe 0f 0b 48 89 de RSP: 0018:ffff8881ddfbf6f8 EFLAGS: 00010282 RAX: 000000000000004e RBX: ffff8881f2c27888 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff87678560 RDI: ffffffff8a19ca60 RBP: ffff8881ddfbf710 R08: ffffed103ed25081 R09: ffffed103ed25080 R10: ffffed103ed25080 R11: ffff8881f6928407 R12: dead000000000200 R13: dead000000000100 R14: ffff8881c62ed300 R15: ffff8881c62ed380 FS: 0000000000000000(0000) GS:ffff8881f6900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000004d04d0 CR3: 000000000846d003 CR4: 00000000001606e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400