bisecting fixing commit since 14b58326976de6ef3998eefec1dd7f8b38b97a75 building syzkaller on f721e4a097714a9054b9fe1aadf427afbbd2c157 testing commit 14b58326976de6ef3998eefec1dd7f8b38b97a75 with gcc (GCC) 8.1.0 kernel signature: dee793d9875b6e675f34006840454251ad12c097a7e46e0ebf9428714b9f5379 run #0: crashed: BUG: corrupted list in bt_accept_unlink run #1: crashed: KASAN: use-after-free Read in bt_accept_enqueue run #2: crashed: KASAN: use-after-free Read in bt_accept_enqueue run #3: OK run #4: OK run #5: OK run #6: OK run #7: OK run #8: OK run #9: OK testing current HEAD 6b6446efedb27c2766745a04f9b5d4449f51391d testing commit 6b6446efedb27c2766745a04f9b5d4449f51391d with gcc (GCC) 8.1.0 kernel signature: aa219d46e59ee2d6379b1a2471b6abe637cac064423d2879393820fe52134dee run #0: crashed: KASAN: use-after-free Read in bt_accept_enqueue run #1: crashed: KASAN: use-after-free Read in bt_accept_enqueue run #2: crashed: KASAN: use-after-free Read in bt_accept_enqueue run #3: crashed: KASAN: use-after-free Read in bt_accept_enqueue run #4: crashed: KASAN: use-after-free Read in bt_accept_enqueue run #5: OK run #6: OK run #7: OK run #8: OK run #9: OK revisions tested: 2, total time: 36m7.070651506s (build: 16m41.313212694s, test: 18m48.563286048s) the crash still happens on HEAD commit msg: Linux 4.14.204 crash: KASAN: use-after-free Read in bt_accept_enqueue Bluetooth: Wrong link type (-22) Bluetooth: Wrong link type (-22) Bluetooth: Wrong link type (-22) Bluetooth: Wrong link type (-22) ================================================================== BUG: KASAN: use-after-free in __list_add_valid+0x8f/0xb0 lib/list_debug.c:26 Read of size 8 at addr ffff888092f1b790 by task kworker/u5:5/11350 CPU: 1 PID: 11350 Comm: kworker/u5:5 Not tainted 4.14.204-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: hci2 hci_rx_work Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x14b/0x1f1 lib/dump_stack.c:58 print_address_description.cold.6+0x9/0x1ca mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report.cold.7+0x11a/0x2d4 mm/kasan/report.c:409 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:430 __list_add_valid+0x8f/0xb0 lib/list_debug.c:26 __list_add include/linux/list.h:60 [inline] list_add_tail include/linux/list.h:93 [inline] bt_accept_enqueue+0x1e7/0x3d0 net/bluetooth/af_bluetooth.c:168 l2cap_sock_new_connection_cb+0x102/0x180 net/bluetooth/l2cap_sock.c:1268 l2cap_connect+0x35a/0x1280 net/bluetooth/l2cap_core.c:3869 l2cap_connect_req net/bluetooth/l2cap_core.c:3980 [inline] l2cap_bredr_sig_cmd net/bluetooth/l2cap_core.c:5415 [inline] l2cap_sig_channel net/bluetooth/l2cap_core.c:5798 [inline] l2cap_recv_frame+0x1cd0/0x9e10 net/bluetooth/l2cap_core.c:7023 l2cap_recv_acldata+0x756/0x8a0 net/bluetooth/l2cap_core.c:7594 hci_acldata_packet net/bluetooth/hci_core.c:4066 [inline] hci_rx_work+0x5d4/0x8d0 net/bluetooth/hci_core.c:4249 process_one_work+0x74f/0x1620 kernel/workqueue.c:2116 worker_thread+0xcc/0xed0 kernel/workqueue.c:2250 kthread+0x338/0x400 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Allocated by task 1202: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack mm/kasan/kasan.c:447 [inline] set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc.part.1+0x62/0xf0 mm/kasan/kasan.c:551 kasan_kmalloc+0xaf/0xc0 mm/kasan/kasan.c:536 __do_kmalloc mm/slab.c:3720 [inline] __kmalloc+0x15d/0x410 mm/slab.c:3729 kmalloc include/linux/slab.h:493 [inline] sk_prot_alloc+0x196/0x240 net/core/sock.c:1467 sk_alloc+0x34/0xc20 net/core/sock.c:1521 l2cap_sock_alloc.constprop.4+0x28/0x1e0 net/bluetooth/l2cap_sock.c:1618 l2cap_sock_new_connection_cb+0xd8/0x180 net/bluetooth/l2cap_sock.c:1257 l2cap_connect+0x35a/0x1280 net/bluetooth/l2cap_core.c:3869 l2cap_connect_req net/bluetooth/l2cap_core.c:3980 [inline] l2cap_bredr_sig_cmd net/bluetooth/l2cap_core.c:5415 [inline] l2cap_sig_channel net/bluetooth/l2cap_core.c:5798 [inline] l2cap_recv_frame+0x1cd0/0x9e10 net/bluetooth/l2cap_core.c:7023 l2cap_recv_acldata+0x756/0x8a0 net/bluetooth/l2cap_core.c:7594 hci_acldata_packet net/bluetooth/hci_core.c:4066 [inline] hci_rx_work+0x5d4/0x8d0 net/bluetooth/hci_core.c:4249 process_one_work+0x74f/0x1620 kernel/workqueue.c:2116 worker_thread+0xcc/0xed0 kernel/workqueue.c:2250 kthread+0x338/0x400 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Freed by task 1202: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack mm/kasan/kasan.c:447 [inline] set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0xab/0x190 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3496 [inline] kfree+0xcc/0x270 mm/slab.c:3815 sk_prot_free net/core/sock.c:1504 [inline] __sk_destruct+0x47e/0x5a0 net/core/sock.c:1582 sk_destruct+0x83/0xb0 net/core/sock.c:1597 __sk_free+0x47/0x1f0 net/core/sock.c:1605 sk_free+0x1a/0x20 net/core/sock.c:1616 sock_put include/net/sock.h:1662 [inline] l2cap_sock_kill.part.2+0x52/0x60 net/bluetooth/l2cap_sock.c:1056 l2cap_sock_kill net/bluetooth/l2cap_sock.c:1325 [inline] l2cap_sock_close_cb+0x84/0xa0 net/bluetooth/l2cap_sock.c:1324 l2cap_disconnect_req net/bluetooth/l2cap_core.c:4355 [inline] l2cap_bredr_sig_cmd net/bluetooth/l2cap_core.c:5432 [inline] l2cap_sig_channel net/bluetooth/l2cap_core.c:5798 [inline] l2cap_recv_frame+0x443f/0x9e10 net/bluetooth/l2cap_core.c:7023 l2cap_recv_acldata+0x756/0x8a0 net/bluetooth/l2cap_core.c:7594 hci_acldata_packet net/bluetooth/hci_core.c:4066 [inline] hci_rx_work+0x5d4/0x8d0 net/bluetooth/hci_core.c:4249 process_one_work+0x74f/0x1620 kernel/workqueue.c:2116 worker_thread+0xcc/0xed0 kernel/workqueue.c:2250 kthread+0x338/0x400 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 The buggy address belongs to the object at ffff888092f1b340 which belongs to the cache kmalloc-2048 of size 2048 The buggy address is located 1104 bytes inside of 2048-byte region [ffff888092f1b340, ffff888092f1bb40) The buggy address belongs to the page: page:ffffea00024bc680 count:1 mapcount:0 mapping:ffff888092f1a240 index:0x0 compound_mapcount: 0 flags: 0xfffe0000008100(slab|head) raw: 00fffe0000008100 ffff888092f1a240 0000000000000000 0000000100000003 raw: ffffea00024a0320 ffffea0002adbd20 ffff8880b6400c40 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888092f1b680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888092f1b700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888092f1b780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888092f1b800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888092f1b880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================