bisecting fixing commit since 14b58326976de6ef3998eefec1dd7f8b38b97a75 building syzkaller on ff51e5229e0ee846d2fd687cb0dbca13de758c66 testing commit 14b58326976de6ef3998eefec1dd7f8b38b97a75 with gcc (GCC) 8.4.1 20210217 kernel signature: b4104e9684d061fc1119ce4fa871f5c6b781c361cea2f411d2725a068f958b83 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 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 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 Read in __queue_work run #13: crashed: KASAN: use-after-free Write in hci_conn_del 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: use-after-free Read in __queue_work testing current HEAD 670d6552eda8ff0c5f396d3d6f0174237917c66c testing commit 670d6552eda8ff0c5f396d3d6f0174237917c66c with gcc (GCC) 8.4.1 20210217 kernel signature: d8fa39f357cf8d5b437cbfe6662bea8a0a8922da1a9f78bd28e05db11dd811a1 run #0: crashed: KASAN: use-after-free Write in hci_conn_del run #1: crashed: KASAN: slab-out-of-bounds Write in hci_conn_del run #2: crashed: KASAN: slab-out-of-bounds Write in hci_conn_del 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: 25m58.403980695s (build: 15m8.563804041s, test: 10m27.635385428s) the crash still happens on HEAD commit msg: Linux 4.14.227 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 ffff8881f4ee9048 by task syz-executor.5/5772 CPU: 0 PID: 5772 Comm: syz-executor.5 Not tainted 4.14.227-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:1622 hci_unregister_dev+0x163/0x790 net/bluetooth/hci_core.c:3193 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:00007fff367d9cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 000000000000053a RCX: 0000000000464909 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000043 RBP: 00000000004ae1ea R08: 000000000000000b R09: 000000000001cac5 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000001cb3c R14: 000000000001cac5 R15: 000000000000000f Allocated by task 3349: 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 user_path_at_empty+0x1e/0x40 fs/namei.c:2631 user_path_at include/linux/namei.h:57 [inline] vfs_statx+0xb6/0x130 fs/stat.c:185 vfs_lstat include/linux/fs.h:3070 [inline] SYSC_newlstat fs/stat.c:350 [inline] SyS_newlstat+0x7d/0xc0 fs/stat.c:344 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb Freed by task 3349: 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 filename_lookup.part.19+0x22c/0x340 fs/namei.c:2386 filename_lookup fs/namei.c:2370 [inline] user_path_at_empty+0x39/0x40 fs/namei.c:2631 user_path_at include/linux/namei.h:57 [inline] vfs_statx+0xb6/0x130 fs/stat.c:185 vfs_lstat include/linux/fs.h:3070 [inline] SYSC_newlstat fs/stat.c:350 [inline] SyS_newlstat+0x7d/0xc0 fs/stat.c:344 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 ffff8881f4ee8880 which belongs to the cache names_cache of size 4096 The buggy address is located 1992 bytes inside of 4096-byte region [ffff8881f4ee8880, ffff8881f4ee9880) The buggy address belongs to the page: page:ffffea0007d3ba00 count:1 mapcount:0 mapping:ffff8881f4ee8880 index:0x0 compound_mapcount: 0 flags: 0x17ffe0000008100(slab|head) raw: 017ffe0000008100 ffff8881f4ee8880 0000000000000000 0000000100000001 raw: ffffea00074f79a0 ffffea0007527ea0 ffff8881f621a0c0 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8881f4ee8f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881f4ee8f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8881f4ee9000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881f4ee9080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881f4ee9100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== batman_adv: batadv0: Interface deactivated: batadv_slave_0 batman_adv: batadv0: Removing interface: batadv_slave_0 batman_adv: batadv0: Interface deactivated: batadv_slave_1 batman_adv: batadv0: Removing interface: batadv_slave_1 device bridge_slave_1 left promiscuous mode bridge0: port 2(bridge_slave_1) entered disabled state device bridge_slave_0 left promiscuous mode bridge0: port 1(bridge_slave_0) entered disabled state device veth1_macvtap left promiscuous mode device veth0_macvtap left promiscuous mode device veth1_vlan left promiscuous mode device veth0_vlan left promiscuous mode device hsr_slave_1 left promiscuous mode device hsr_slave_0 left promiscuous mode team0 (unregistering): Port device team_slave_1 removed team0 (unregistering): Port device team_slave_0 removed bond0 (unregistering): Releasing backup interface bond_slave_1 bond0 (unregistering): Releasing backup interface bond_slave_0 bond0 (unregistering): Released all slaves IPVS: ftp: loaded support on port[0] = 21 Bluetooth: hci4 command 0x0405 tx timeout chnl_net:caif_netlink_parms(): no params data found bridge0: port 1(bridge_slave_0) entered blocking state bridge0: port 1(bridge_slave_0) entered disabled state device bridge_slave_0 entered promiscuous mode bridge0: port 2(bridge_slave_1) entered blocking state bridge0: port 2(bridge_slave_1) entered disabled state device bridge_slave_1 entered promiscuous mode bond0: Enslaving bond_slave_0 as an active interface with an up link bond0: Enslaving bond_slave_1 as an active interface with an up link IPv6: ADDRCONF(NETDEV_UP): team_slave_0: link is not ready team0: Port device team_slave_0 added IPv6: ADDRCONF(NETDEV_UP): team_slave_1: link is not ready team0: Port device team_slave_1 added batman_adv: batadv0: Adding interface: batadv_slave_0 batman_adv: batadv0: The MTU of interface batadv_slave_0 is too small (1500) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to 1560 would solve the problem. batman_adv: batadv0: Not using interface batadv_slave_0 (retrying later): interface not active batman_adv: batadv0: Adding interface: batadv_slave_1 batman_adv: batadv0: The MTU of interface batadv_slave_1 is too small (1500) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to 1560 would solve the problem. batman_adv: batadv0: Not using interface batadv_slave_1 (retrying later): interface not active IPv6: ADDRCONF(NETDEV_UP): bridge_slave_0: link is not ready IPv6: ADDRCONF(NETDEV_UP): bridge_slave_1: link is not ready device hsr_slave_0 entered promiscuous mode device hsr_slave_1 entered promiscuous mode IPv6: ADDRCONF(NETDEV_UP): hsr_slave_0: link is not ready IPv6: ADDRCONF(NETDEV_UP): hsr_slave_1: link is not ready bridge0: port 2(bridge_slave_1) entered blocking state bridge0: port 2(bridge_slave_1) entered forwarding state bridge0: port 1(bridge_slave_0) entered blocking state bridge0: port 1(bridge_slave_0) entered forwarding state IPv6: ADDRCONF(NETDEV_UP): bond0: link is not ready 8021q: adding VLAN 0 to HW filter on device bond0 IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready bridge0: port 1(bridge_slave_0) entered disabled state bridge0: port 2(bridge_slave_1) entered disabled state IPv6: ADDRCONF(NETDEV_UP): team0: link is not ready 8021q: adding VLAN 0 to HW filter on device team0 IPv6: ADDRCONF(NETDEV_CHANGE): bridge_slave_0: link becomes ready bridge0: port 1(bridge_slave_0) entered blocking state bridge0: port 1(bridge_slave_0) entered forwarding state hsr0: Slave A (hsr_slave_0) is not up; please bring it up to get a fully working HSR network hsr0: Slave B (hsr_slave_1) is not up; please bring it up to get a fully working HSR network IPv6: ADDRCONF(NETDEV_UP): hsr0: link is not ready IPv6: ADDRCONF(NETDEV_CHANGE): bridge_slave_1: link becomes ready bridge0: port 2(bridge_slave_1) entered blocking state bridge0: port 2(bridge_slave_1) entered forwarding state IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_1: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): hsr0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): team0: link becomes ready IPv6: ADDRCONF(NETDEV_UP): vxcan0: link is not ready IPv6: ADDRCONF(NETDEV_CHANGE): vxcan0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): vxcan1: link becomes ready 8021q: adding VLAN 0 to HW filter on device batadv0 IPv6: ADDRCONF(NETDEV_UP): veth0_virt_wifi: link is not ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0_virt_wifi: link becomes ready 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 IPv6: ADDRCONF(NETDEV_CHANGE): veth0_vlan: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): vlan0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): vlan1: link becomes ready device veth0_vlan entered promiscuous mode device veth1_vlan entered promiscuous mode IPv6: ADDRCONF(NETDEV_UP): macvlan0: link is not ready IPv6: ADDRCONF(NETDEV_UP): macvlan1: link is not ready IPv6: ADDRCONF(NETDEV_UP): veth0_macvtap: link is not ready IPv6: ADDRCONF(NETDEV_CHANGE): macvlan0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): macvlan1: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0_macvtap: link becomes ready device veth0_macvtap entered promiscuous mode IPv6: ADDRCONF(NETDEV_UP): macvtap0: link is not ready device veth1_macvtap entered promiscuous mode IPv6: ADDRCONF(NETDEV_UP): veth0_to_batadv: link is not ready IPv6: ADDRCONF(NETDEV_UP): veth1_to_batadv: link is not ready batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3d) already exists on: batadv_slave_0 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3d) already exists on: batadv_slave_0 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3d) already exists on: batadv_slave_0 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3d) already exists on: batadv_slave_0 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3d) already exists on: batadv_slave_0 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! batman_adv: batadv0: Interface activated: batadv_slave_0 IPv6: ADDRCONF(NETDEV_CHANGE): bond0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_batadv: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): macvtap0: link becomes ready batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! IPv6: ADDRCONF(NETDEV_UP): batadv_slave_1: link is not ready 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