bisecting fixing commit since d7e78d08fa77acdea351c8f628f49ca9a0e1029a
building syzkaller on 318430cbb3b2ceefe51518ecccabbdabb32ffe3b
testing commit d7e78d08fa77acdea351c8f628f49ca9a0e1029a with gcc (GCC) 8.1.0
kernel signature: 22d1c6451417a291b882520c786f1da61335947ab445347cf86b79d6a7178abf
all runs: crashed: KASAN: slab-out-of-bounds Read in hci_le_meta_evt
testing current HEAD 5b7a52cd2eef952cee8a72512ef370bcdef46636
testing commit 5b7a52cd2eef952cee8a72512ef370bcdef46636 with gcc (GCC) 8.1.0
kernel signature: 7fd7224d202b8e85f260cc2f48bdc8702ace7ba13b24c1e1d15af2dcc12c2c40
all runs: crashed: KASAN: slab-out-of-bounds Read in hci_le_meta_evt
revisions tested: 2, total time: 22m17.882091137s (build: 15m59.832182285s, test: 5m47.299988955s)
the crash still happens on HEAD
commit msg: Linux 4.14.202
crash: KASAN: slab-out-of-bounds Read in hci_le_meta_evt
IPv6: ADDRCONF(NETDEV_UP): veth0_macvtap: link is not ready
device veth0_vlan entered promiscuous mode
IPv6: ADDRCONF(NETDEV_UP): veth1_macvtap: link is not ready
device veth1_vlan entered promiscuous mode
==================================================================
BUG: KASAN: slab-out-of-bounds in hci_le_direct_adv_report_evt net/bluetooth/hci_event.c:5153 [inline]
BUG: KASAN: slab-out-of-bounds in hci_le_meta_evt+0x3611/0x42e0 net/bluetooth/hci_event.c:5193
Read of size 1 at addr ffff8880a04c7a4c by task kworker/u5:7/6548
IPv6: ADDRCONF(NETDEV_UP): macvlan0: link is not ready

CPU: 0 PID: 6548 Comm: kworker/u5:7 Not tainted 4.14.202-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
IPv6: ADDRCONF(NETDEV_CHANGE): macvlan0: link becomes ready
Workqueue: hci0 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
IPv6: ADDRCONF(NETDEV_CHANGE): veth1_macvtap: link becomes ready
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report.cold.7+0x11a/0x2d4 mm/kasan/report.c:409
 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:427
 hci_le_direct_adv_report_evt net/bluetooth/hci_event.c:5153 [inline]
 hci_le_meta_evt+0x3611/0x42e0 net/bluetooth/hci_event.c:5193
IPv6: ADDRCONF(NETDEV_CHANGE): veth0_macvtap: link becomes ready
 hci_event_packet+0x141a/0x70c0 net/bluetooth/hci_event.c:5429
IPv6: ADDRCONF(NETDEV_UP): veth0_vlan: link is not ready
IPv6: ADDRCONF(NETDEV_UP): vlan0: link is not ready
IPv6: ADDRCONF(NETDEV_UP): vlan1: link is not ready
 hci_rx_work+0x30e/0x8d0 net/bluetooth/hci_core.c:4244
 process_one_work+0x74f/0x1620 kernel/workqueue.c:2116
 worker_thread+0xcc/0xed0 kernel/workqueue.c:2250
 kthread+0x338/0x400 kernel/kthread.c:232
device veth0_macvtap entered promiscuous mode
IPv6: ADDRCONF(NETDEV_UP): macvtap0: link is not ready
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
IPv6: ADDRCONF(NETDEV_UP): macvlan1: link is not ready

IPv6: ADDRCONF(NETDEV_UP): veth1_vlan: link is not ready
Allocated by task 7824:
 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_node mm/slab.c:3682 [inline]
 __kmalloc_node_track_caller+0x50/0x70 mm/slab.c:3696
 __kmalloc_reserve.isra.7+0x2c/0xc0 net/core/skbuff.c:137
 __alloc_skb+0xc1/0x540 net/core/skbuff.c:205
 alloc_skb include/linux/skbuff.h:980 [inline]
 bt_skb_alloc include/net/bluetooth/bluetooth.h:336 [inline]
 vhci_get_user drivers/bluetooth/hci_vhci.c:180 [inline]
 vhci_write+0xa8/0x3e0 drivers/bluetooth/hci_vhci.c:299
 call_write_iter include/linux/fs.h:1778 [inline]
 new_sync_write fs/read_write.c:469 [inline]
 __vfs_write+0x413/0x840 fs/read_write.c:482
 vfs_write+0x150/0x4f0 fs/read_write.c:544
 SYSC_write fs/read_write.c:590 [inline]
 SyS_write+0x100/0x250 fs/read_write.c:582
 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

IPv6: ADDRCONF(NETDEV_CHANGE): macvlan1: link becomes ready
Freed by task 0:
(stack is not available)
IPv6: ADDRCONF(NETDEV_CHANGE): macvtap0: link becomes ready

The buggy address belongs to the object at ffff8880a04c7840
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 12 bytes to the right of
 512-byte region [ffff8880a04c7840, ffff8880a04c7a40)
The buggy address belongs to the page:
page:ffffea00028131c0 count:1 mapcount:0 mapping:ffff8880a04c70c0 index:0x0
flags: 0xfffe0000000100(slab)
raw: 00fffe0000000100 ffff8880a04c70c0 0000000000000000 0000000100000006
raw: ffffea00027ecd20 ffffea00028473e0 ffff8880b6400940 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a04c7900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
IPv6: ADDRCONF(NETDEV_CHANGE): veth1_vlan: link becomes ready
 ffff8880a04c7980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880a04c7a00: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
                                              ^
 ffff8880a04c7a80: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
 ffff8880a04c7b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================