bisecting fixing commit since c076c79e03c6094e578df5d210fde808b3ad32e6 building syzkaller on 4ca1c0ea446d2c09b1fb49a85ae645e3754f1058 testing commit c076c79e03c6094e578df5d210fde808b3ad32e6 with gcc (GCC) 8.1.0 kernel signature: 7ba0a59f5e55d311d061b424ca56e454e5fa1cab4f84b1e5238ca067482c03b0 run #0: crashed: BUG: corrupted list in l2cap_chan_put run #1: crashed: BUG: corrupted list in l2cap_chan_put run #2: crashed: BUG: corrupted list in l2cap_chan_put run #3: crashed: BUG: corrupted list in l2cap_chan_put run #4: crashed: BUG: corrupted list in l2cap_chan_put run #5: crashed: BUG: corrupted list in l2cap_chan_put run #6: crashed: BUG: corrupted list in l2cap_chan_put run #7: crashed: BUG: corrupted list in l2cap_chan_put run #8: crashed: BUG: corrupted list in l2cap_chan_put run #9: crashed: KASAN: use-after-free Read in l2cap_chan_put testing current HEAD f5d8eef067acee3fda37137f4a08c0d3f6427a8e testing commit f5d8eef067acee3fda37137f4a08c0d3f6427a8e with gcc (GCC) 8.1.0 kernel signature: bc076baf58ff26143cd2d601b1c20e8792c3ad33fb80b0c047970f7609544bfb all runs: crashed: BUG: corrupted list in l2cap_chan_put revisions tested: 2, total time: 39m23.526395378s (build: 18m31.682231955s, test: 20m9.334988927s) the crash still happens on HEAD commit msg: Linux 4.19.154 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, ffff8880ab0db108->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: 1292 Comm: kworker/u5:4 Not tainted 4.19.154-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+0x26/0x58 lib/list_debug.c:45 Code: 1d fe 0f 0b 4c 89 e2 48 89 de 48 c7 c7 a0 80 67 87 e8 b6 a4 1d fe 0f 0b 4c 89 ea 48 89 de 48 c7 c7 40 80 67 87 e8 a2 a4 1d fe <0f> 0b 48 89 de 48 c7 c7 60 81 67 87 e8 91 a4 1d fe 0f 0b 48 89 de RSP: 0018:ffff88808e36f6f8 EFLAGS: 00010282 RAX: 000000000000004e RBX: ffff8880ab0db108 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff87677da0 RDI: ffffffff8a19da60 RBP: ffff88808e36f710 R08: ffffed10174e5081 R09: ffffed10174e5080 R10: ffffed10174e5080 R11: ffff8880ba728407 R12: dead000000000200 R13: dead000000000100 R14: ffff8880b4281780 R15: ffff8880b4281800 FS: 0000000000000000(0000) GS:ffff8880ba700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000004d04d0 CR3: 00000000ad548000 CR4: 00000000001406e0 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 d746201f69309ddc ]--- 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 a0 80 67 87 e8 b6 a4 1d fe 0f 0b 4c 89 ea 48 89 de 48 c7 c7 40 80 67 87 e8 a2 a4 1d fe <0f> 0b 48 89 de 48 c7 c7 60 81 67 87 e8 91 a4 1d fe 0f 0b 48 89 de RSP: 0018:ffff88808e36f6f8 EFLAGS: 00010282 RAX: 000000000000004e RBX: ffff8880ab0db108 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff87677da0 RDI: ffffffff8a19da60 RBP: ffff88808e36f710 R08: ffffed10174e5081 R09: ffffed10174e5080 R10: ffffed10174e5080 R11: ffff8880ba728407 R12: dead000000000200 R13: dead000000000100 R14: ffff8880b4281780 R15: ffff8880b4281800 FS: 0000000000000000(0000) GS:ffff8880ba700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000004d04d0 CR3: 00000000ad548000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400