bisecting fixing commit since c076c79e03c6094e578df5d210fde808b3ad32e6 building syzkaller on 0487ea6f5d997a8363eba0d2eb0ea7a925444555 testing commit c076c79e03c6094e578df5d210fde808b3ad32e6 with gcc (GCC) 8.4.1 20210217 kernel signature: 8ec9491994b6dd92e44d6c5403a7b31a116be305f265eb0d307e4441d9448664 all runs: crashed: BUG: corrupted list in l2cap_chan_put testing current HEAD 2965db2e004cf9c92b87c1f559e9812c0ae878c1 testing commit 2965db2e004cf9c92b87c1f559e9812c0ae878c1 with gcc (GCC) 8.4.1 20210217 kernel signature: d3abd35d1734305f94cbc45807cfa6490022852ceab93e6343a3259d693f0e63 all runs: crashed: BUG: corrupted list in l2cap_chan_put revisions tested: 2, total time: 30m31.620995268s (build: 16m4.582771151s, test: 13m57.469911178s) the crash still happens on HEAD commit msg: Linux 4.19.188 crash: BUG: corrupted list in l2cap_chan_put bond0 (unregistering): Releasing backup interface bond_slave_0 bond0 (unregistering): Released all slaves Bluetooth: hci0: command 0x041b tx timeout list_del corruption, ffff8881c5a16e88->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: 7239 Comm: kworker/u5:1 Not tainted 4.19.188-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 40 a0 67 87 e8 e7 67 f9 ff 0f 0b 4c 89 ea 48 89 de 48 c7 c7 e0 9f 67 87 e8 d3 67 f9 ff <0f> 0b 48 89 de 48 c7 c7 00 a1 67 87 e8 c2 67 f9 ff 0f 0b 48 89 de RSP: 0018:ffff8881df49f6f8 EFLAGS: 00010282 RAX: 000000000000004e RBX: ffff8881c5a16e88 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff87679d40 RDI: ffffffff8a1a0aa0 RBP: ffff8881df49f710 R08: ffffed103ed25081 R09: ffffed103ed25080 R10: ffffed103ed25080 R11: ffff8881f6928407 R12: dead000000000200 R13: dead000000000100 R14: ffff8881d39e4780 R15: ffff8881d39e4800 FS: 0000000000000000(0000) GS:ffff8881f6900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000007bc608 CR3: 000000000846d005 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: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 03754a96d7dd9698 ]--- 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 40 a0 67 87 e8 e7 67 f9 ff 0f 0b 4c 89 ea 48 89 de 48 c7 c7 e0 9f 67 87 e8 d3 67 f9 ff <0f> 0b 48 89 de 48 c7 c7 00 a1 67 87 e8 c2 67 f9 ff 0f 0b 48 89 de RSP: 0018:ffff8881df49f6f8 EFLAGS: 00010282 RAX: 000000000000004e RBX: ffff8881c5a16e88 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff87679d40 RDI: ffffffff8a1a0aa0 RBP: ffff8881df49f710 R08: ffffed103ed25081 R09: ffffed103ed25080 R10: ffffed103ed25080 R11: ffff8881f6928407 R12: dead000000000200 R13: dead000000000100 R14: ffff8881d39e4780 R15: ffff8881d39e4800 FS: 0000000000000000(0000) GS:ffff8881f6900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000007bc608 CR3: 000000000846d005 CR4: 00000000001606e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400