BUG: unable to handle kernel NULL pointer dereference in fuse_conn_put BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 113f8e067 P4D 113f8e067 PUD 113f34067 PMD 0 Oops: 0000 [#1] PREEMPT SMP CPU: 0 PID: 6472 Comm: syz-fuzzer Not tainted 5.14.0-next-20210903-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:29 [inline] RIP: 0010:atomic_read include/linux/atomic/atomic-instrumented.h:28 [inline] RIP: 0010:fuse_conn_put fs/fuse/inode.c:827 [inline] RIP: 0010:fuse_conn_put+0x10d/0x190 fs/fuse/inode.c:814 Code: ed 0f 88 82 00 00 00 e8 81 7d 83 ff 31 ff 89 ee e8 18 85 83 ff 85 ed 74 70 e8 6f 7d 83 ff 48 8b ab f8 01 00 00 bf 01 00 00 00 <44> 8b 65 00 44 89 e6 e8 f7 84 83 ff 41 83 fc 01 75 64 e8 4c 7d 83 RSP: 0018:ffffc9000101be08 EFLAGS: 00010293 RAX: 0000000000000000 RBX: ffff888113e6cc30 RCX: 0000000000000000 RDX: ffff8881061c5000 RSI: ffffffff81b1a2e1 RDI: 0000000000000001 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001 R10: ffffffff81b1a2d8 R11: 0000000000000000 R12: ffffffff85883960 R13: ffffffff85883a64 R14: ffff88811b3a658c R15: ffff8881004819c0 FS: 000000c0004f0890(0000) GS:ffff88813bc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000010b383000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: fuse_dev_free+0x79/0xa0 fs/fuse/inode.c:1324 fuse_dev_release+0xfd/0x160 fs/fuse/dev.c:2205 __fput+0x105/0x430 fs/file_table.c:280 task_work_run+0x73/0xb0 kernel/task_work.c:164 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop kernel/entry/common.c:175 [inline] exit_to_user_mode_prepare+0x171/0x180 kernel/entry/common.c:209 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x1d/0x40 kernel/entry/common.c:302 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4af19b Code: fb ff eb bd e8 a6 b6 fb ff e9 61 ff ff ff cc e8 9b 82 fb ff 48 8b 7c 24 10 48 8b 74 24 18 48 8b 54 24 20 48 8b 44 24 08 0f 05 <48> 3d 01 f0 ff ff 76 20 48 c7 44 24 28 ff ff ff ff 48 c7 44 24 30 RSP: 002b:000000c00032d450 EFLAGS: 00000206 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 000000c00001e800 RCX: 00000000004af19b RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006 RBP: 000000c00032d490 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000077 R13: 0000000000000076 R14: 0000000000000200 R15: 000000c00006e820 Modules linked in: CR2: 0000000000000000 ---[ end trace 2bc0abef3a096ef5 ]--- RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:29 [inline] RIP: 0010:atomic_read include/linux/atomic/atomic-instrumented.h:28 [inline] RIP: 0010:fuse_conn_put fs/fuse/inode.c:827 [inline] RIP: 0010:fuse_conn_put+0x10d/0x190 fs/fuse/inode.c:814 Code: ed 0f 88 82 00 00 00 e8 81 7d 83 ff 31 ff 89 ee e8 18 85 83 ff 85 ed 74 70 e8 6f 7d 83 ff 48 8b ab f8 01 00 00 bf 01 00 00 00 <44> 8b 65 00 44 89 e6 e8 f7 84 83 ff 41 83 fc 01 75 64 e8 4c 7d 83 RSP: 0018:ffffc9000101be08 EFLAGS: 00010293 RAX: 0000000000000000 RBX: ffff888113e6cc30 RCX: 0000000000000000 RDX: ffff8881061c5000 RSI: ffffffff81b1a2e1 RDI: 0000000000000001 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001 R10: ffffffff81b1a2d8 R11: 0000000000000000 R12: ffffffff85883960 R13: ffffffff85883a64 R14: ffff88811b3a658c R15: ffff8881004819c0 FS: 000000c0004f0890(0000) GS:ffff88813bc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000010b383000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: ed in (%dx),%eax 1: 0f 88 82 00 00 00 js 0x89 7: e8 81 7d 83 ff callq 0xff837d8d c: 31 ff xor %edi,%edi e: 89 ee mov %ebp,%esi 10: e8 18 85 83 ff callq 0xff83852d 15: 85 ed test %ebp,%ebp 17: 74 70 je 0x89 19: e8 6f 7d 83 ff callq 0xff837d8d 1e: 48 8b ab f8 01 00 00 mov 0x1f8(%rbx),%rbp 25: bf 01 00 00 00 mov $0x1,%edi * 2a: 44 8b 65 00 mov 0x0(%rbp),%r12d <-- trapping instruction 2e: 44 89 e6 mov %r12d,%esi 31: e8 f7 84 83 ff callq 0xff83852d 36: 41 83 fc 01 cmp $0x1,%r12d 3a: 75 64 jne 0xa0 3c: e8 .byte 0xe8 3d: 4c 7d 83 rex.WR jge 0xffffffc3 Warning: Permanently added '10.128.1.52' (ECDSA) to the list of known hosts. 2021/09/04 09:02:42 fuzzer started 2021/09/04 09:02:43 connecting to host at 10.128.0.169:45383 2021/09/04 09:02:43 checking machine... 2021/09/04 09:02:43 checking revisions... 2021/09/04 09:02:43 testing simple program... executing program executing program syzkaller login: [ 49.359358][ T6476] chnl_net:caif_netlink_parms(): no params data found [ 49.385672][ T6476] bridge0: port 1(bridge_slave_0) entered blocking state [ 49.392741][ T6476] bridge0: port 1(bridge_slave_0) entered disabled state [ 49.400403][ T6476] device bridge_slave_0 entered promiscuous mode [ 49.407860][ T6476] bridge0: port 2(bridge_slave_1) entered blocking state [ 49.415466][ T6476] bridge0: port 2(bridge_slave_1) entered disabled state [ 49.422930][ T6476] device bridge_slave_1 entered promiscuous mode [ 49.435052][ T6476] bond0: (slave bond_slave_0): Enslaving as an active interface with an up link [ 49.445116][ T6476] bond0: (slave bond_slave_1): Enslaving as an active interface with an up link [ 49.460179][ T6476] team0: Port device team_slave_0 added [ 49.466684][ T6476] team0: Port device team_slave_1 added [ 49.479046][ T6476] batman_adv: batadv0: Adding interface: batadv_slave_0 [ 49.486175][ T6476] 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. [ 49.512933][ T6476] batman_adv: batadv0: Not using interface batadv_slave_0 (retrying later): interface not active [ 49.524081][ T6476] batman_adv: batadv0: Adding interface: batadv_slave_1 [ 49.531271][ T6476] 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. executing program [ 49.557482][ T6476] batman_adv: batadv0: Not using interface batadv_slave_1 (retrying later): interface not active [ 49.574711][ T6476] device hsr_slave_0 entered promiscuous mode [ 49.581307][ T6476] device hsr_slave_1 entered promiscuous mode [ 49.613670][ T6476] netdevsim netdevsim0 netdevsim0: renamed from eth0 [ 49.621544][ T6476] netdevsim netdevsim0 netdevsim1: renamed from eth1 [ 49.630519][ T6476] netdevsim netdevsim0 netdevsim2: renamed from eth2 [ 49.638570][ T6476] netdevsim netdevsim0 netdevsim3: renamed from eth3 [ 49.650411][ T6476] bridge0: port 2(bridge_slave_1) entered blocking state [ 49.657844][ T6476] bridge0: port 2(bridge_slave_1) entered forwarding state [ 49.665096][ T6476] bridge0: port 1(bridge_slave_0) entered blocking state [ 49.672451][ T6476] bridge0: port 1(bridge_slave_0) entered forwarding state [ 49.690425][ T6476] 8021q: adding VLAN 0 to HW filter on device bond0 [ 49.699786][ T1395] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 49.708520][ T1395] bridge0: port 1(bridge_slave_0) entered disabled state [ 49.716812][ T1395] bridge0: port 2(bridge_slave_1) entered disabled state [ 49.724304][ T1395] IPv6: ADDRCONF(NETDEV_CHANGE): bond0: link becomes ready [ 49.733376][ T6476] 8021q: adding VLAN 0 to HW filter on device team0 [ 49.741786][ T7] IPv6: ADDRCONF(NETDEV_CHANGE): bridge_slave_0: link becomes ready [ 49.750929][ T7] bridge0: port 1(bridge_slave_0) entered blocking state [ 49.758296][ T7] bridge0: port 1(bridge_slave_0) entered forwarding state [ 49.767157][ T6807] IPv6: ADDRCONF(NETDEV_CHANGE): bridge_slave_1: link becomes ready [ 49.776169][ T6807] bridge0: port 2(bridge_slave_1) entered blocking state [ 49.783326][ T6807] bridge0: port 2(bridge_slave_1) entered forwarding state [ 49.794783][ T7] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_0: link becomes ready [ 49.803167][ T7] IPv6: ADDRCONF(NETDEV_CHANGE): team0: link becomes ready [ 49.815050][ T6476] hsr0: Slave A (hsr_slave_0) is not up; please bring it up to get a fully working HSR network [ 49.825579][ T6476] hsr0: Slave B (hsr_slave_1) is not up; please bring it up to get a fully working HSR network [ 49.837196][ T6807] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready [ 49.845634][ T6807] IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_0: link becomes ready [ 49.853831][ T6807] IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_1: link becomes ready [ 49.862480][ T6807] IPv6: ADDRCONF(NETDEV_CHANGE): hsr0: link becomes ready [ 49.873502][ T7] IPv6: ADDRCONF(NETDEV_CHANGE): vxcan0: link becomes ready [ 49.881009][ T7] IPv6: ADDRCONF(NETDEV_CHANGE): vxcan1: link becomes ready [ 49.890606][ T6476] 8021q: adding VLAN 0 to HW filter on device batadv0 [ 49.903007][ T6807] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_virt_wifi: link becomes ready [ 49.915600][ T2938] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_vlan: link becomes ready [ 49.924045][ T2938] IPv6: ADDRCONF(NETDEV_CHANGE): vlan0: link becomes ready [ 49.932086][ T2938] IPv6: ADDRCONF(NETDEV_CHANGE): vlan1: link becomes ready [ 49.940849][ T6476] device veth0_vlan entered promiscuous mode [ 49.949688][ T6476] device veth1_vlan entered promiscuous mode [ 49.961495][ T2938] IPv6: ADDRCONF(NETDEV_CHANGE): macvlan0: link becomes ready [ 49.969663][ T2938] IPv6: ADDRCONF(NETDEV_CHANGE): macvlan1: link becomes ready [ 49.977878][ T2938] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_macvtap: link becomes ready [ 49.987357][ T6476] device veth0_macvtap entered promiscuous mode [ 49.995494][ T6476] device veth1_macvtap entered promiscuous mode [ 50.007227][ T6476] batman_adv: batadv0: Interface activated: batadv_slave_0 [ 50.014644][ T6808] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_batadv: link becomes ready [ 50.024045][ T6808] IPv6: ADDRCONF(NETDEV_CHANGE): macvtap0: link becomes ready [ 50.033839][ T6476] batman_adv: batadv0: Interface activated: batadv_slave_1 [ 50.041252][ T2938] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_batadv: link becomes ready [ 50.053975][ T6476] netdevsim netdevsim0 netdevsim0: set [1, 0] type 2 family 0 port 6081 - 0 [ 50.064275][ T6476] netdevsim netdevsim0 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0 [ 50.073376][ T6476] netdevsim netdevsim0 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0 [ 50.082689][ T6476] netdevsim netdevsim0 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0 [ 50.114096][ T6343] wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50 [ 50.125298][ T6343] wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50 [ 50.134301][ T6808] IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready [ 50.145740][ T147] wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50 [ 50.154220][ T147] wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50 2021/09/04 09:02:52 building call list... [ 50.162001][ T6808] IPv6: ADDRCONF(NETDEV_CHANGE): wlan1: link becomes ready [ 50.333422][ T147] netdevsim netdevsim0 netdevsim3 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0 [ 51.471065][ T6472] BUG: kernel NULL pointer dereference, address: 0000000000000000 [ 51.478899][ T6472] #PF: supervisor read access in kernel mode [ 51.484867][ T6472] #PF: error_code(0x0000) - not-present page [ 51.490958][ T6472] PGD 113f8e067 P4D 113f8e067 PUD 113f34067 PMD 0 [ 51.497445][ T6472] Oops: 0000 [#1] PREEMPT SMP [ 51.502123][ T6472] CPU: 0 PID: 6472 Comm: syz-fuzzer Not tainted 5.14.0-next-20210903-syzkaller #0 [ 51.511409][ T6472] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 51.521589][ T6472] RIP: 0010:fuse_conn_put+0x10d/0x190 [ 51.526960][ T6472] Code: ed 0f 88 82 00 00 00 e8 81 7d 83 ff 31 ff 89 ee e8 18 85 83 ff 85 ed 74 70 e8 6f 7d 83 ff 48 8b ab f8 01 00 00 bf 01 00 00 00 <44> 8b 65 00 44 89 e6 e8 f7 84 83 ff 41 83 fc 01 75 64 e8 4c 7d 83 [ 51.546647][ T6472] RSP: 0018:ffffc9000101be08 EFLAGS: 00010293 [ 51.552705][ T6472] RAX: 0000000000000000 RBX: ffff888113e6cc30 RCX: 0000000000000000 [ 51.560675][ T6472] RDX: ffff8881061c5000 RSI: ffffffff81b1a2e1 RDI: 0000000000000001 [ 51.568716][ T6472] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001 [ 51.576931][ T6472] R10: ffffffff81b1a2d8 R11: 0000000000000000 R12: ffffffff85883960 [ 51.584993][ T6472] R13: ffffffff85883a64 R14: ffff88811b3a658c R15: ffff8881004819c0 [ 51.593099][ T6472] FS: 000000c0004f0890(0000) GS:ffff88813bc00000(0000) knlGS:0000000000000000 [ 51.602129][ T6472] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 51.608860][ T6472] CR2: 0000000000000000 CR3: 000000010b383000 CR4: 00000000001506f0 [ 51.616827][ T6472] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 51.624905][ T6472] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 51.632949][ T6472] Call Trace: [ 51.636216][ T6472] fuse_dev_free+0x79/0xa0 [ 51.640620][ T6472] fuse_dev_release+0xfd/0x160 [ 51.645366][ T6472] ? cuse_class_waiting_show+0x30/0x30 [ 51.650809][ T6472] __fput+0x105/0x430 [ 51.654842][ T6472] task_work_run+0x73/0xb0 [ 51.659354][ T6472] exit_to_user_mode_prepare+0x171/0x180 [ 51.665102][ T6472] syscall_exit_to_user_mode+0x1d/0x40 [ 51.670636][ T6472] do_syscall_64+0x42/0xb0 [ 51.675051][ T6472] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 51.680931][ T6472] RIP: 0033:0x4af19b [ 51.684819][ T6472] Code: fb ff eb bd e8 a6 b6 fb ff e9 61 ff ff ff cc e8 9b 82 fb ff 48 8b 7c 24 10 48 8b 74 24 18 48 8b 54 24 20 48 8b 44 24 08 0f 05 <48> 3d 01 f0 ff ff 76 20 48 c7 44 24 28 ff ff ff ff 48 c7 44 24 30 [ 51.704415][ T6472] RSP: 002b:000000c00032d450 EFLAGS: 00000206 ORIG_RAX: 0000000000000003 [ 51.712910][ T6472] RAX: 0000000000000000 RBX: 000000c00001e800 RCX: 00000000004af19b [ 51.720966][ T6472] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006 [ 51.729024][ T6472] RBP: 000000c00032d490 R08: 0000000000000001 R09: 0000000000000000 [ 51.737082][ T6472] R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000077 [ 51.745292][ T6472] R13: 0000000000000076 R14: 0000000000000200 R15: 000000c00006e820 [ 51.753570][ T6472] Modules linked in: [ 51.757543][ T6472] CR2: 0000000000000000 [ 51.763663][ T6472] ---[ end trace 2bc0abef3a096ef5 ]--- [ 51.769545][ T6472] RIP: 0010:fuse_conn_put+0x10d/0x190 [ 51.775197][ T6472] Code: ed 0f 88 82 00 00 00 e8 81 7d 83 ff 31 ff 89 ee e8 18 85 83 ff 85 ed 74 70 e8 6f 7d 83 ff 48 8b ab f8 01 00 00 bf 01 00 00 00 <44> 8b 65 00 44 89 e6 e8 f7 84 83 ff 41 83 fc 01 75 64 e8 4c 7d 83 [ 51.795042][ T6472] RSP: 0018:ffffc9000101be08 EFLAGS: 00010293 [ 51.801474][ T6472] RAX: 0000000000000000 RBX: ffff888113e6cc30 RCX: 0000000000000000 [ 51.809932][ T6472] RDX: ffff8881061c5000 RSI: ffffffff81b1a2e1 RDI: 0000000000000001 [ 51.818112][ T6472] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001 [ 51.826521][ T6472] R10: ffffffff81b1a2d8 R11: 0000000000000000 R12: ffffffff85883960 [ 51.834504][ T6472] R13: ffffffff85883a64 R14: ffff88811b3a658c R15: ffff8881004819c0 [ 51.843012][ T6472] FS: 000000c0004f0890(0000) GS:ffff88813bc00000(0000) knlGS:0000000000000000 [ 51.852569][ T6472] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 51.859421][ T6472] CR2: 0000000000000000 CR3: 000000010b383000 CR4: 00000000001506f0 [ 51.867669][ T6472] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 51.875770][ T6472] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 51.883845][ T6472] Kernel panic - not syncing: Fatal exception [ 51.890074][ T6472] Kernel Offset: disabled [ 51.894382][ T6472] Rebooting in 86400 seconds..