====================================================== WARNING: possible circular locking dependency detected 4.14.163-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.0/15723 is trying to acquire lock: (&ovl_i_mutex_key[depth]#2){+.+.}, at: [] inode_lock include/linux/fs.h:718 [inline] (&ovl_i_mutex_key[depth]#2){+.+.}, at: [] bprm_fill_uid fs/exec.c:1522 [inline] (&ovl_i_mutex_key[depth]#2){+.+.}, at: [] prepare_binprm+0x31c/0x7f0 fs/exec.c:1557 but task is already holding lock: (&sig->cred_guard_mutex){+.+.}, at: [] prepare_bprm_creds+0x55/0x120 fs/exec.c:1389 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&sig->cred_guard_mutex){+.+.}: lock_acquire+0x16f/0x430 kernel/locking/lockdep.c:3994 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xe8/0x1470 kernel/locking/mutex.c:893 mutex_lock_killable_nested+0x16/0x20 kernel/locking/mutex.c:923 do_io_accounting+0x1d6/0x7b0 fs/proc/base.c:2726 proc_tgid_io_accounting+0x23/0x30 fs/proc/base.c:2775 proc_single_show+0xf0/0x160 fs/proc/base.c:761 autofs4:pid:15730:autofs4_fill_super: called with bogus options seq_read+0x51a/0x1280 fs/seq_file.c:237 __vfs_read+0x105/0x6a0 fs/read_write.c:411 vfs_read+0x137/0x350 fs/read_write.c:447 SYSC_read fs/read_write.c:574 [inline] SyS_read+0xfd/0x230 fs/read_write.c:567 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 -> #2 (&p->lock){+.+.}: lock_acquire+0x16f/0x430 kernel/locking/lockdep.c:3994 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xe8/0x1470 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 seq_read+0xc1/0x1280 fs/seq_file.c:165 do_loop_readv_writev fs/read_write.c:695 [inline] do_loop_readv_writev fs/read_write.c:682 [inline] do_iter_read+0x3e2/0x5b0 fs/read_write.c:919 vfs_readv+0xd3/0x130 fs/read_write.c:981 kernel_readv fs/splice.c:361 [inline] default_file_splice_read+0x421/0x870 fs/splice.c:416 do_splice_to+0x105/0x170 fs/splice.c:880 splice_direct_to_actor+0x222/0x7b0 fs/splice.c:952 do_splice_direct+0x18d/0x230 fs/splice.c:1061 do_sendfile+0x4db/0xbd0 fs/read_write.c:1441 SYSC_sendfile64 fs/read_write.c:1502 [inline] SyS_sendfile64+0x102/0x110 fs/read_write.c:1488 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 -> #1 (sb_writers#4){.+.+}: lock_acquire+0x16f/0x430 kernel/locking/lockdep.c:3994 percpu_down_read_preempt_disable include/linux/percpu-rwsem.h:36 [inline] percpu_down_read include/linux/percpu-rwsem.h:59 [inline] __sb_start_write+0x1ae/0x2f0 fs/super.c:1363 sb_start_write include/linux/fs.h:1548 [inline] mnt_want_write+0x3f/0xb0 fs/namespace.c:386 ovl_want_write+0x76/0xa0 fs/overlayfs/util.c:25 ovl_do_remove+0x68/0xbd0 fs/overlayfs/dir.c:759 ovl_unlink+0x18/0x20 fs/overlayfs/dir.c:792 vfs_unlink+0x281/0x480 fs/namei.c:4024 do_unlinkat+0x33d/0x600 fs/namei.c:4089 SYSC_unlink fs/namei.c:4136 [inline] SyS_unlink+0x1b/0x20 fs/namei.c:4134 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 -> #0 (&ovl_i_mutex_key[depth]#2){+.+.}: check_prev_add kernel/locking/lockdep.c:1901 [inline] check_prevs_add kernel/locking/lockdep.c:2018 [inline] validate_chain kernel/locking/lockdep.c:2460 [inline] __lock_acquire+0x2cb3/0x4620 kernel/locking/lockdep.c:3487 lock_acquire+0x16f/0x430 kernel/locking/lockdep.c:3994 down_write+0x38/0x90 kernel/locking/rwsem.c:54 inode_lock include/linux/fs.h:718 [inline] bprm_fill_uid fs/exec.c:1522 [inline] prepare_binprm+0x31c/0x7f0 fs/exec.c:1557 do_execveat_common.isra.0+0xd81/0x1dd0 fs/exec.c:1783 do_execve fs/exec.c:1847 [inline] SYSC_execve fs/exec.c:1928 [inline] SyS_execve+0x39/0x50 fs/exec.c:1923 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 other info that might help us debug this: Chain exists of: &ovl_i_mutex_key[depth]#2 --> &p->lock --> &sig->cred_guard_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sig->cred_guard_mutex); lock(&p->lock); lock(&sig->cred_guard_mutex); lock(&ovl_i_mutex_key[depth]#2); *** DEADLOCK *** 1 lock held by syz-executor.0/15723: #0: (&sig->cred_guard_mutex){+.+.}, at: [] prepare_bprm_creds+0x55/0x120 fs/exec.c:1389 stack backtrace: CPU: 1 PID: 15723 Comm: syz-executor.0 Not tainted 4.14.163-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+0x142/0x197 lib/dump_stack.c:58 print_circular_bug.isra.0.cold+0x1cc/0x28f kernel/locking/lockdep.c:1258 check_prev_add kernel/locking/lockdep.c:1901 [inline] check_prevs_add kernel/locking/lockdep.c:2018 [inline] validate_chain kernel/locking/lockdep.c:2460 [inline] __lock_acquire+0x2cb3/0x4620 kernel/locking/lockdep.c:3487 lock_acquire+0x16f/0x430 kernel/locking/lockdep.c:3994 down_write+0x38/0x90 kernel/locking/rwsem.c:54 inode_lock include/linux/fs.h:718 [inline] bprm_fill_uid fs/exec.c:1522 [inline] prepare_binprm+0x31c/0x7f0 fs/exec.c:1557 do_execveat_common.isra.0+0xd81/0x1dd0 fs/exec.c:1783 do_execve fs/exec.c:1847 [inline] SYSC_execve fs/exec.c:1928 [inline] SyS_execve+0x39/0x50 fs/exec.c:1923 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x45af49 RSP: 002b:00007fe64485cc78 EFLAGS: 00000246 ORIG_RAX: 000000000000003b RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045af49 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000140 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fe64485d6d4 R13: 00000000004c198f R14: 00000000004d6b10 R15: 00000000ffffffff autofs4:pid:15739:autofs4_fill_super: called with bogus options autofs4:pid:15748:autofs4_fill_super: called with bogus options autofs4:pid:15760:autofs4_fill_super: called with bogus options autofs4:pid:15762:autofs4_fill_super: called with bogus options IPv6: ADDRCONF(NETDEV_CHANGE): vcan0: link becomes ready chnl_net:chnl_net_open(): err: Unable to register and open device, Err:-19 kauditd_printk_skb: 35 callbacks suppressed audit: type=1804 audit(1578820766.922:4336): pid=15778 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op="invalid_pcr" cause="open_writers" comm="syz-executor.2" name="/root/syzkaller-testdir735506959/syzkaller.qDTwDf/315/bus" dev="sda1" ino=17141 res=1 caif:caif_disconnect_client(): nothing to disconnect chnl_net:chnl_flowctrl_cb(): NET flowctrl func called flow: CLOSE/DEINIT chnl_net:chnl_net_open(): state disconnected A link change request failed with some changes committed already. Interface caif0 may have been left with an inconsistent configuration, please check. autofs4:pid:15789:autofs4_fill_super: called with bogus options audit: type=1800 audit(1578820766.922:4337): pid=15778 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op="collect_data" cause="failed(directio)" comm="syz-executor.2" name="bus" dev="sda1" ino=17141 res=0 audit: type=1804 audit(1578820766.932:4338): pid=15778 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op="invalid_pcr" cause="ToMToU" comm="syz-executor.2" name="/root/syzkaller-testdir735506959/syzkaller.qDTwDf/315/bus" dev="sda1" ino=17141 res=1 audit: type=1804 audit(1578820766.982:4339): pid=15785 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op="invalid_pcr" cause="open_writers" comm="syz-executor.2" name="/root/syzkaller-testdir735506959/syzkaller.qDTwDf/316/bus" dev="sda1" ino=17141 res=1 audit: type=1800 audit(1578820766.982:4340): pid=15785 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op="collect_data" cause="failed(directio)" comm="syz-executor.2" name="bus" dev="sda1" ino=17141 res=0 audit: type=1804 audit(1578820766.982:4341): pid=15785 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op="invalid_pcr" cause="ToMToU" comm="syz-executor.2" name="/root/syzkaller-testdir735506959/syzkaller.qDTwDf/316/bus" dev="sda1" ino=17141 res=1 audit: type=1804 audit(1578820767.202:4342): pid=15795 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op="invalid_pcr" cause="open_writers" comm="syz-executor.2" name="/root/syzkaller-testdir735506959/syzkaller.qDTwDf/317/bus" dev="sda1" ino=17141 res=1 audit: type=1800 audit(1578820767.202:4343): pid=15795 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op="collect_data" cause="failed(directio)" comm="syz-executor.2" name="bus" dev="sda1" ino=17141 res=0 IPv6: ADDRCONF(NETDEV_CHANGE): vcan0: link becomes ready chnl_net:chnl_net_open(): err: Unable to register and open device, Err:-19 caif:caif_disconnect_client(): nothing to disconnect chnl_net:chnl_flowctrl_cb(): NET flowctrl func called flow: CLOSE/DEINIT chnl_net:chnl_net_open(): state disconnected A link change request failed with some changes committed already. Interface caif0 may have been left with an inconsistent configuration, please check. audit: type=1804 audit(1578820767.372:4344): pid=15803 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op="invalid_pcr" cause="open_writers" comm="syz-executor.2" name="/root/syzkaller-testdir735506959/syzkaller.qDTwDf/318/bus" dev="sda1" ino=17141 res=1 audit: type=1800 audit(1578820767.412:4345): pid=15803 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op="collect_data" cause="failed(directio)" comm="syz-executor.2" name="bus" dev="sda1" ino=17141 res=0 IPv6: ADDRCONF(NETDEV_CHANGE): vcan0: link becomes ready chnl_net:chnl_net_open(): err: Unable to register and open device, Err:-19 caif:caif_disconnect_client(): nothing to disconnect chnl_net:chnl_flowctrl_cb(): NET flowctrl func called flow: CLOSE/DEINIT chnl_net:chnl_net_open(): state disconnected A link change request failed with some changes committed already. Interface caif0 may have been left with an inconsistent configuration, please check. autofs4:pid:15816:autofs4_fill_super: called with bogus options IPv6: ADDRCONF(NETDEV_CHANGE): vcan0: link becomes ready chnl_net:chnl_net_open(): err: Unable to register and open device, Err:-19 caif:caif_disconnect_client(): nothing to disconnect chnl_net:chnl_flowctrl_cb(): NET flowctrl func called flow: CLOSE/DEINIT chnl_net:chnl_net_open(): state disconnected A link change request failed with some changes committed already. Interface caif0 may have been left with an inconsistent configuration, please check. autofs4:pid:15842:autofs4_fill_super: called with bogus options autofs4:pid:15842:autofs4_fill_super: called with bogus options IPv6: ADDRCONF(NETDEV_CHANGE): vcan0: link becomes ready chnl_net:chnl_net_open(): err: Unable to register and open device, Err:-19 caif:caif_disconnect_client(): nothing to disconnect chnl_net:chnl_flowctrl_cb(): NET flowctrl func called flow: CLOSE/DEINIT chnl_net:chnl_net_open(): state disconnected A link change request failed with some changes committed already. Interface caif0 may have been left with an inconsistent configuration, please check. autofs4:pid:15863:autofs4_fill_super: called with bogus options IPv6: ADDRCONF(NETDEV_UP): bridge0: link is not ready IPv6: ADDRCONF(NETDEV_CHANGE): vcan0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): vcan0: link becomes ready 8021q: adding VLAN 0 to HW filter on device bond0 IPv6: ADDRCONF(NETDEV_UP): team0: link is not ready 8021q: adding VLAN 0 to HW filter on device team0 chnl_net:chnl_net_open(): err: Unable to register and open device, Err:-19 caif:caif_disconnect_client(): nothing to disconnect chnl_net:chnl_flowctrl_cb(): NET flowctrl func called flow: CLOSE/DEINIT chnl_net:chnl_net_open(): state disconnected A link change request failed with some changes committed already. Interface caif0 may have been left with an inconsistent configuration, please check. autofs4:pid:15923:autofs4_fill_super: called with bogus options autofs4:pid:15930:autofs4_fill_super: called with bogus options autofs4:pid:15930:autofs4_fill_super: called with bogus options autofs4:pid:15951:autofs4_fill_super: called with bogus options autofs4:pid:15962:autofs4_fill_super: called with bogus options autofs4:pid:15969:autofs4_fill_super: called with bogus options kauditd_printk_skb: 7 callbacks suppressed audit: type=1804 audit(1578820772.632:4353): pid=16034 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op="invalid_pcr" cause="open_writers" comm="syz-executor.2" name="/root/syzkaller-testdir735506959/syzkaller.qDTwDf/336/bus" dev="sda1" ino=17696 res=1 audit: type=1804 audit(1578820772.682:4354): pid=16034 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op="invalid_pcr" cause="ToMToU" comm="syz-executor.2" name="/root/syzkaller-testdir735506959/syzkaller.qDTwDf/336/bus" dev="sda1" ino=17696 res=1 autofs4:pid:16043:autofs4_fill_super: called with bogus options autofs4:pid:16048:autofs4_fill_super: called with bogus options audit: type=1804 audit(1578820772.762:4355): pid=16047 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op="invalid_pcr" cause="open_writers" comm="syz-executor.2" name="/root/syzkaller-testdir735506959/syzkaller.qDTwDf/337/bus" dev="sda1" ino=17679 res=1 audit: type=1804 audit(1578820772.762:4356): pid=16047 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op="invalid_pcr" cause="ToMToU" comm="syz-executor.2" name="/root/syzkaller-testdir735506959/syzkaller.qDTwDf/337/bus" dev="sda1" ino=17679 res=1 autofs4:pid:16069:autofs4_fill_super: called with bogus options audit: type=1804 audit(1578820773.502:4357): pid=16068 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op="invalid_pcr" cause="open_writers" comm="syz-executor.2" name="/root/syzkaller-testdir735506959/syzkaller.qDTwDf/338/bus" dev="sda1" ino=17710 res=1 audit: type=1804 audit(1578820773.522:4358): pid=16068 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op="invalid_pcr" cause="ToMToU" comm="syz-executor.2" name="/root/syzkaller-testdir735506959/syzkaller.qDTwDf/338/bus" dev="sda1" ino=17710 res=1 audit: type=1804 audit(1578820773.612:4359): pid=16078 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op="invalid_pcr" cause="open_writers" comm="syz-executor.2" name="/root/syzkaller-testdir735506959/syzkaller.qDTwDf/339/bus" dev="sda1" ino=17704 res=1 audit: type=1804 audit(1578820773.642:4360): pid=16078 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op="invalid_pcr" cause="ToMToU" comm="syz-executor.2" name="/root/syzkaller-testdir735506959/syzkaller.qDTwDf/339/bus" dev="sda1" ino=17704 res=1 audit: type=1804 audit(1578820773.682:4361): pid=16085 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op="invalid_pcr" cause="open_writers" comm="syz-executor.2" name="/root/syzkaller-testdir735506959/syzkaller.qDTwDf/340/bus" dev="sda1" ino=17689 res=1 audit: type=1804 audit(1578820773.682:4362): pid=16085 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op="invalid_pcr" cause="ToMToU" comm="syz-executor.2" name="/root/syzkaller-testdir735506959/syzkaller.qDTwDf/340/bus" dev="sda1" ino=17689 res=1 autofs4:pid:16069:autofs4_fill_super: called with bogus options autofs4:pid:16093:autofs4_fill_super: called with bogus options autofs4:pid:16093:autofs4_fill_super: called with bogus options