bisecting fixing commit since 14b58326976de6ef3998eefec1dd7f8b38b97a75 building syzkaller on ff51e5229e0ee846d2fd687cb0dbca13de758c66 testing commit 14b58326976de6ef3998eefec1dd7f8b38b97a75 with gcc (GCC) 8.4.1 20210217 kernel signature: 045d1724715486cf8559f04ff5b859d06098f5a4dedc1fc0de69eb2639fa988e run #0: crashed: KASAN: use-after-free Write in hci_conn_del run #1: crashed: KASAN: use-after-free Write in hci_conn_del run #2: crashed: KASAN: use-after-free Write in hci_conn_del run #3: crashed: KASAN: use-after-free Write in hci_conn_del run #4: crashed: KASAN: use-after-free Read in __queue_work run #5: crashed: KASAN: use-after-free Write in hci_conn_del run #6: crashed: KASAN: use-after-free Write in hci_conn_del run #7: crashed: KASAN: use-after-free Write in hci_conn_del run #8: crashed: KASAN: use-after-free Write in hci_conn_del run #9: crashed: KASAN: use-after-free Write in hci_conn_del run #10: crashed: KASAN: use-after-free Write in hci_conn_del run #11: crashed: KASAN: use-after-free Write in hci_conn_del run #12: crashed: KASAN: use-after-free Write in hci_conn_del run #13: crashed: possible deadlock in hci_dev_do_close run #14: crashed: KASAN: use-after-free Write in hci_conn_del run #15: crashed: KASAN: use-after-free Write in hci_conn_del run #16: crashed: KASAN: use-after-free Write in hci_conn_del run #17: crashed: KASAN: use-after-free Write in hci_conn_del run #18: crashed: KASAN: use-after-free Read in __queue_work run #19: crashed: KASAN: slab-out-of-bounds Write in hci_conn_del testing current HEAD 3242aa3a635c0958671ee1e4b0958dcc7c4e5c79 testing commit 3242aa3a635c0958671ee1e4b0958dcc7c4e5c79 with gcc (GCC) 8.4.1 20210217 kernel signature: 6ddf982c96e1039b0e7496e76eb5fc0ada6269524f68d4012ab2b702e68949b9 run #0: crashed: WARNING: ODEBUG bug in bt_link_release run #1: crashed: KASAN: use-after-free Write in hci_conn_del run #2: crashed: WARNING: ODEBUG bug in bt_link_release run #3: crashed: KASAN: use-after-free Write in hci_conn_del run #4: crashed: KASAN: use-after-free Write in hci_conn_del run #5: crashed: KASAN: use-after-free Write in hci_conn_del run #6: crashed: KASAN: use-after-free Write in hci_conn_del run #7: crashed: KASAN: use-after-free Write in hci_conn_del run #8: crashed: KASAN: use-after-free Write in hci_conn_del run #9: crashed: KASAN: use-after-free Write in hci_conn_del revisions tested: 2, total time: 27m36.359675116s (build: 15m52.547561941s, test: 10m46.027681646s) the crash still happens on HEAD commit msg: Linux 4.14.222 crash: KASAN: use-after-free Write in hci_conn_del batman_adv: batadv0: Interface activated: batadv_slave_1 IPv6: ADDRCONF(NETDEV_CHANGE): batadv_slave_1: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_batadv: link becomes ready ================================================================== BUG: KASAN: use-after-free in hci_conn_del+0x587/0x5e0 net/bluetooth/hci_conn.c:596 Write of size 8 at addr ffff8881f45ff408 by task syz-executor.4/5814 CPU: 1 PID: 5814 Comm: syz-executor.4 Not tainted 4.14.222-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x14b/0x1e7 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 mm/kasan/report.c:409 [inline] kasan_report.cold.7+0x11a/0x2d3 mm/kasan/report.c:393 __asan_report_store8_noabort+0x17/0x20 mm/kasan/report.c:435 hci_conn_del+0x587/0x5e0 net/bluetooth/hci_conn.c:596 hci_conn_hash_flush+0x168/0x200 net/bluetooth/hci_conn.c:1394 hci_dev_do_close+0x47a/0xb10 net/bluetooth/hci_core.c:1620 hci_unregister_dev+0x163/0x790 net/bluetooth/hci_core.c:3191 vhci_release+0x6b/0xe0 drivers/bluetooth/hci_vhci.c:354 __fput+0x232/0x740 fs/file_table.c:210 ____fput+0x9/0x10 fs/file_table.c:244 task_work_run+0xe5/0x170 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x98b/0x2c90 kernel/exit.c:868 do_group_exit+0xf8/0x2c0 kernel/exit.c:965 SYSC_exit_group kernel/exit.c:976 [inline] SyS_exit_group+0x18/0x20 kernel/exit.c:974 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x464909 RSP: 002b:00007fff8e44ca38 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000728 RCX: 0000000000464909 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000043 RBP: 00000000004ae1ea R08: 000000000000000b R09: 000000000002b9c1 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000002b9d6 R14: 000000000002b9c1 R15: 000000000000000f Allocated by task 24762: 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 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489 kmem_cache_alloc+0x12e/0x3e0 mm/slab.c:3552 getname_flags+0xb8/0x510 fs/namei.c:138 getname+0xd/0x10 fs/namei.c:209 do_sys_open+0x14b/0x350 fs/open.c:1075 SYSC_open fs/open.c:1099 [inline] SyS_open+0x19/0x20 fs/open.c:1094 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb Freed by task 24762: 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] kmem_cache_free+0x80/0x2d0 mm/slab.c:3758 putname+0xa8/0xe0 fs/namei.c:259 do_sys_open+0x16d/0x350 fs/open.c:1090 SYSC_open fs/open.c:1099 [inline] SyS_open+0x19/0x20 fs/open.c:1094 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb The buggy address belongs to the object at ffff8881f45fe4c0 which belongs to the cache names_cache of size 4096 The buggy address is located 3912 bytes inside of 4096-byte region [ffff8881f45fe4c0, ffff8881f45ff4c0) The buggy address belongs to the page: page:ffffea0007d17f80 count:1 mapcount:0 mapping:ffff8881f45fe4c0 index:0x0 compound_mapcount: 0 flags: 0x17ffe0000008100(slab|head) raw: 017ffe0000008100 ffff8881f45fe4c0 0000000000000000 0000000100000001 raw: ffffea00075058a0 ffffea00073e63a0 ffff8881f621a0c0 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8881f45ff300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881f45ff380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8881f45ff400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881f45ff480: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff8881f45ff500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================