bisecting fixing commit since f6d5cb9e2c06f7d583dd9f4f7cca21d13d78c32a building syzkaller on 816e0689d7d9d8321f8bf360740f0e516aee15ca testing commit f6d5cb9e2c06f7d583dd9f4f7cca21d13d78c32a with gcc (GCC) 8.1.0 kernel signature: fb5478a478292ea455bfe13173d77545734fb385c3d1ac3ef90ab1aa4718cacf all runs: crashed: KASAN: slab-out-of-bounds Read in hci_le_meta_evt testing current HEAD d09b80172c22df7a5e2ec58aa1a0fbe8914752e7 testing commit d09b80172c22df7a5e2ec58aa1a0fbe8914752e7 with gcc (GCC) 8.1.0 kernel signature: 1298a237f02d95311e1c2e8ff943a7e1d302e228857101d06aedcc1f75376389 all runs: crashed: KASAN: slab-out-of-bounds Read in hci_le_meta_evt revisions tested: 2, total time: 24m24.705612959s (build: 17m47.715043123s, test: 5m53.827940997s) the crash still happens on HEAD commit msg: Linux 4.19.147 crash: KASAN: slab-out-of-bounds Read in hci_le_meta_evt batman_adv: batadv0: Interface activated: batadv_slave_0 IPv6: ADDRCONF(NETDEV_UP): veth1_to_batadv: link is not ready IPv6: ADDRCONF(NETDEV_CHANGE): batadv_slave_0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_batadv: link becomes ready ================================================================== BUG: KASAN: slab-out-of-bounds in hci_le_direct_adv_report_evt net/bluetooth/hci_event.c:5619 [inline] BUG: KASAN: slab-out-of-bounds in hci_le_meta_evt+0x2e9f/0x3950 net/bluetooth/hci_event.c:5660 Read of size 1 at addr ffff88808ce1b54c by task kworker/u5:5/6659 IPv6: ADDRCONF(NETDEV_CHANGE): batadv_slave_0: link becomes ready CPU: 1 PID: 6659 Comm: kworker/u5:5 Not tainted 4.19.147-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_batadv: link becomes ready Workqueue: hci1 hci_rx_work Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x17c/0x22a lib/dump_stack.c:118 print_address_description.cold.6+0x9/0x211 mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.7+0x242/0x307 mm/kasan/report.c:412 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:430 hci_le_direct_adv_report_evt net/bluetooth/hci_event.c:5619 [inline] hci_le_meta_evt+0x2e9f/0x3950 net/bluetooth/hci_event.c:5660 hci_event_packet+0x1934/0x7174 net/bluetooth/hci_event.c:5904 hci_rx_work+0x31b/0x8e0 net/bluetooth/hci_core.c:4359 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 Allocated by task 7913: save_stack mm/kasan/kasan.c:448 [inline] set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc.part.1+0x62/0xf0 mm/kasan/kasan.c:553 kasan_kmalloc+0xaf/0xc0 mm/kasan/kasan.c:538 __do_kmalloc_node mm/slab.c:3689 [inline] __kmalloc_node_track_caller+0x50/0x70 mm/slab.c:3703 __kmalloc_reserve.isra.9+0x2c/0xc0 net/core/skbuff.c:137 __alloc_skb+0xd7/0x580 net/core/skbuff.c:205 alloc_skb include/linux/skbuff.h:995 [inline] bt_skb_alloc include/net/bluetooth/bluetooth.h:339 [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:1821 [inline] new_sync_write fs/read_write.c:474 [inline] __vfs_write+0x443/0x890 fs/read_write.c:487 vfs_write+0x150/0x4d0 fs/read_write.c:549 ksys_write+0x103/0x260 fs/read_write.c:599 __do_sys_write fs/read_write.c:611 [inline] __se_sys_write fs/read_write.c:608 [inline] __x64_sys_write+0x6e/0xb0 fs/read_write.c:608 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 0: (stack is not available) The buggy address belongs to the object at ffff88808ce1b340 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 12 bytes to the right of 512-byte region [ffff88808ce1b340, ffff88808ce1b540) The buggy address belongs to the page: page:ffffea00023386c0 count:1 mapcount:0 mapping:ffff88812c29c940 index:0x0 flags: 0xfffe0000000100(slab) raw: 00fffe0000000100 ffffea0002328548 ffffea0002336548 ffff88812c29c940 raw: 0000000000000000 ffff88808ce1b0c0 0000000100000006 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88808ce1b400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88808ce1b480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff88808ce1b500: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc ^ ffff88808ce1b580: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00 ffff88808ce1b600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ================================================================== Bluetooth: hci4: unknown advertising packet type: 0x88 Bluetooth: hci4: unknown advertising packet type: 0x4e batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1 Bluetooth: hci4: unknown advertising packet type: 0xff Bluetooth: hci4: unknown advertising packet type: 0xff Bluetooth: hci4: unknown advertising packet type: 0x88 Bluetooth: hci4: unknown advertising packet type: 0x88 Bluetooth: hci4: unknown advertising packet type: 0xff Bluetooth: hci4: unknown advertising packet type: 0xff batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! Bluetooth: hci4: unknown advertising packet type: 0x88