bisecting fixing commit since c076c79e03c6094e578df5d210fde808b3ad32e6 building syzkaller on 4ca1c0ea446d2c09b1fb49a85ae645e3754f1058 testing commit c076c79e03c6094e578df5d210fde808b3ad32e6 with gcc (GCC) 8.4.1 20210217 kernel signature: d89f29fe202f2879e5fcaa8ff2552052be18d201741bd4bab68b25e0f89da1f6 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: WARNING: ODEBUG bug in bt_link_release run #5: crashed: WARNING in __queue_work run #6: crashed: KASAN: use-after-free Write in hci_conn_del run #7: crashed: KASAN: slab-out-of-bounds 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: slab-out-of-bounds Write in hci_conn_del run #12: crashed: KASAN: slab-out-of-bounds Write in hci_conn_del run #13: crashed: KASAN: slab-out-of-bounds 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: slab-out-of-bounds Write in hci_conn_del run #18: crashed: KASAN: use-after-free Write in hci_conn_del run #19: OK testing current HEAD 1e986fe9ad15b8406034c504afc5ae76f0a8e852 testing commit 1e986fe9ad15b8406034c504afc5ae76f0a8e852 with gcc (GCC) 8.4.1 20210217 kernel signature: 45bfc784673ec96f03b7f3a998f03210bae29a247c2c7dc96025dab215efca24 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 Read in __queue_work run #9: crashed: KASAN: use-after-free Write in hci_conn_del revisions tested: 2, total time: 39m39.241525836s (build: 25m0.252425532s, test: 14m2.579391601s) the crash still happens on HEAD commit msg: Linux 4.19.191 crash: KASAN: use-after-free Write in hci_conn_del bond0 (unregistering): Releasing backup interface bond_slave_0 bond0 (unregistering): Released all slaves ================================================================== BUG: KASAN: use-after-free in hci_conn_del+0x5a4/0x5f0 net/bluetooth/hci_conn.c:596 Write of size 8 at addr ffff8881dd066ab0 by task syz-executor.1/5921 CPU: 1 PID: 5921 Comm: syz-executor.1 Not tainted 4.19.191-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x17c/0x226 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 mm/kasan/report.c:412 [inline] kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:396 __asan_report_store8_noabort+0x17/0x20 mm/kasan/report.c:438 hci_conn_del+0x5a4/0x5f0 net/bluetooth/hci_conn.c:596 hci_conn_hash_flush+0x168/0x200 net/bluetooth/hci_conn.c:1513 hci_dev_do_close+0x4d2/0xcd0 net/bluetooth/hci_core.c:1668 hci_unregister_dev+0x163/0x7a0 net/bluetooth/hci_core.c:3273 vhci_release+0x6b/0xe0 drivers/bluetooth/hci_vhci.c:354 __fput+0x249/0x7f0 fs/file_table.c:278 ____fput+0x9/0x10 fs/file_table.c:309 task_work_run+0x108/0x180 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0xa6a/0x2d90 kernel/exit.c:870 do_group_exit+0xf8/0x2c0 kernel/exit.c:967 __do_sys_exit_group kernel/exit.c:978 [inline] __se_sys_exit_group kernel/exit.c:976 [inline] __x64_sys_exit_group+0x39/0x40 kernel/exit.c:976 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x464759 Code: Bad RIP value. RSP: 002b:00007ffe176c6938 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00000000000004fb RCX: 0000000000464759 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000043 RBP: 00000000004ae1d2 R08: 000000000000000b R09: 000000000002c07f R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000002c0b3 R14: 000000000002c07f R15: 0000000000000019 Allocated by task 3412: 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 kmem_cache_alloc_trace+0x152/0x3a0 mm/slab.c:3625 kmalloc include/linux/slab.h:515 [inline] kzalloc include/linux/slab.h:709 [inline] kernfs_iop_get_link fs/kernfs/symlink.c:136 [inline] kernfs_iop_get_link+0x59/0x640 fs/kernfs/symlink.c:127 vfs_readlink+0x1b8/0x480 fs/namei.c:4738 do_readlinkat+0x20a/0x2b0 fs/stat.c:406 __do_sys_readlinkat fs/stat.c:421 [inline] __se_sys_readlinkat fs/stat.c:418 [inline] __x64_sys_readlinkat+0x92/0xf0 fs/stat.c:418 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 3412: save_stack mm/kasan/kasan.c:448 [inline] set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x13c/0x220 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3503 [inline] kfree+0xcf/0x220 mm/slab.c:3822 kfree_link+0x9/0x10 fs/libfs.c:1113 do_delayed_call include/linux/delayed_call.h:28 [inline] vfs_readlink+0x124/0x480 fs/namei.c:4743 do_readlinkat+0x20a/0x2b0 fs/stat.c:406 __do_sys_readlinkat fs/stat.c:421 [inline] __se_sys_readlinkat fs/stat.c:418 [inline] __x64_sys_readlinkat+0x92/0xf0 fs/stat.c:418 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8881dd066380 which belongs to the cache kmalloc-4096 of size 4096 The buggy address is located 1840 bytes inside of 4096-byte region [ffff8881dd066380, ffff8881dd067380) The buggy address belongs to the page: page:ffffea0007741980 count:1 mapcount:0 mapping:ffff8881f6400dc0 index:0x0 compound_mapcount: 0 flags: 0x17ffe0000008100(slab|head) raw: 017ffe0000008100 ffffea00076b2308 ffffea0007a02308 ffff8881f6400dc0 raw: 0000000000000000 ffff8881dd066380 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8881dd066980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881dd066a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8881dd066a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881dd066b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881dd066b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== IPVS: ftp: loaded support on port[0] = 21 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 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 IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready 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 Bluetooth: hci2: command 0x0405 tx timeout 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 IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes 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): veth0_to_bond: link becomes ready IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bond: link becomes ready IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_team: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): team0: link becomes ready IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_team: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready IPv6: ADDRCONF(NETDEV_UP): veth0_to_hsr: link is not ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_hsr: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_0: link becomes ready IPv6: ADDRCONF(NETDEV_UP): veth1_to_hsr: link is not ready IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_hsr: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_1: link becomes ready IPv6: ADDRCONF(NETDEV_UP): hsr0: link is not ready IPv6: ADDRCONF(NETDEV_CHANGE): hsr0: link becomes ready IPv6: ADDRCONF(NETDEV_UP): vxcan0: link is not ready IPv6: ADDRCONF(NETDEV_UP): vxcan1: link is not ready IPv6: ADDRCONF(NETDEV_CHANGE): vxcan1: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): vxcan0: 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_UP): veth1_virt_wifi: link is not ready IPv6: ADDRCONF(NETDEV_CHANGE): veth1_virt_wifi: link becomes 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_UP): veth1_vlan: link is not ready IPv6: ADDRCONF(NETDEV_CHANGE): veth1_vlan: link becomes 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_UP): veth1_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): veth1_macvtap: 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): macsec0: link is not ready 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! IPv6: ADDRCONF(NETDEV_UP): batadv_slave_0: link is not ready batman_adv: batadv0: Interface activated: batadv_slave_0 IPv6: ADDRCONF(NETDEV_CHANGE): macvtap0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): macsec0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): batadv_slave_0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_batadv: 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 Bluetooth: hci2: command 0x0405 tx timeout