bisecting fixing commit since c076c79e03c6094e578df5d210fde808b3ad32e6 building syzkaller on 0487ea6f5d997a8363eba0d2eb0ea7a925444555 testing commit c076c79e03c6094e578df5d210fde808b3ad32e6 with gcc (GCC) 8.4.1 20210217 kernel signature: ae62d5f57ca54b6aa1c182771820bfa0e74efd5419891239e33a495636ba19ad 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: 881ae99373b3a7a9f7c77cb0478dc6e31ef246a49ba0e08a65281d05d90ab93e all runs: crashed: BUG: corrupted list in l2cap_chan_put revisions tested: 2, total time: 34m38.378099553s (build: 16m19.221506963s, test: 17m49.561470069s) the crash still happens on HEAD commit msg: Linux 4.19.182 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, ffff8881dc307108->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: 23422 Comm: kworker/u5:0 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:ffff8881f4bff6f8 EFLAGS: 00010282 RAX: 000000000000004e RBX: ffff8881dc307108 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff876789c0 RDI: ffffffff8a19faa0 RBP: ffff8881f4bff710 R08: ffffed103ed05081 R09: ffffed103ed05080 R10: ffffed103ed05080 R11: ffff8881f6828407 R12: dead000000000200 R13: dead000000000100 R14: ffff8881c8925c80 R15: ffff8881c8925d00 FS: 0000000000000000(0000) GS:ffff8881f6800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000137d608 CR3: 000000000846d001 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 db24e64b7d2a7d56 ]--- 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:ffff8881f4bff6f8 EFLAGS: 00010282 RAX: 000000000000004e RBX: ffff8881dc307108 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff876789c0 RDI: ffffffff8a19faa0 RBP: ffff8881f4bff710 R08: ffffed103ed05081 R09: ffffed103ed05080 R10: ffffed103ed05080 R11: ffff8881f6828407 R12: dead000000000200 R13: dead000000000100 R14: ffff8881c8925c80 R15: ffff8881c8925d00 FS: 0000000000000000(0000) GS:ffff8881f6800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000137d608 CR3: 000000000846d001 CR4: 00000000001606f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400