====================================================== WARNING: possible circular locking dependency detected 4.14.177-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.5/15008 is trying to acquire lock: (&sig->cred_guard_mutex){+.+.}, at: [] lock_trace+0x3f/0xc0 fs/proc/base.c:407 but task is already holding lock: (&p->lock){+.+.}, at: [] seq_read+0xba/0x1160 fs/seq_file.c:165 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&p->lock){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xe8/0x1470 kernel/locking/mutex.c:893 seq_read+0xba/0x1160 fs/seq_file.c:165 proc_reg_read+0xf2/0x160 fs/proc/inode.c:217 do_loop_readv_writev fs/read_write.c:695 [inline] do_loop_readv_writev fs/read_write.c:682 [inline] do_iter_read+0x3e3/0x5a0 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+0x41d/0x870 fs/splice.c:416 do_splice_to+0xfb/0x150 fs/splice.c:880 splice_direct_to_actor+0x20a/0x730 fs/splice.c:952 do_splice_direct+0x164/0x210 fs/splice.c:1061 do_sendfile+0x469/0xaf0 fs/read_write.c:1441 SYSC_sendfile64 fs/read_write.c:1502 [inline] SyS_sendfile64+0xff/0x110 fs/read_write.c:1488 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 -> #2 (sb_writers#3){.+.+}: 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+0x1a1/0x2e0 fs/super.c:1363 sb_start_write include/linux/fs.h:1549 [inline] mnt_want_write+0x3a/0xb0 fs/namespace.c:386 ovl_do_remove+0x65/0xb10 fs/overlayfs/dir.c:759 vfs_rmdir fs/namei.c:3908 [inline] vfs_rmdir+0x212/0x410 fs/namei.c:3886 do_rmdir+0x2d1/0x340 fs/namei.c:3968 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 -> #1 (&ovl_i_mutex_dir_key[depth]#2){++++}: down_read+0x37/0xa0 kernel/locking/rwsem.c:24 inode_lock_shared include/linux/fs.h:729 [inline] do_last fs/namei.c:3333 [inline] path_openat+0x185a/0x3c50 fs/namei.c:3569 do_filp_open+0x18e/0x250 fs/namei.c:3603 do_open_execat+0xda/0x430 fs/exec.c:849 do_execveat_common.isra.0+0x694/0x1c70 fs/exec.c:1740 do_execveat fs/exec.c:1858 [inline] SYSC_execveat fs/exec.c:1939 [inline] SyS_execveat+0x49/0x60 fs/exec.c:1931 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 -> #0 (&sig->cred_guard_mutex){+.+.}: lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xe8/0x1470 kernel/locking/mutex.c:893 lock_trace+0x3f/0xc0 fs/proc/base.c:407 proc_pid_stack+0x10b/0x240 fs/proc/base.c:457 proc_single_show+0xe7/0x150 fs/proc/base.c:761 seq_read+0x4d2/0x1160 fs/seq_file.c:237 do_loop_readv_writev fs/read_write.c:695 [inline] do_loop_readv_writev fs/read_write.c:682 [inline] do_iter_read+0x3e3/0x5a0 fs/read_write.c:919 vfs_readv+0xd3/0x130 fs/read_write.c:981 do_preadv+0x161/0x200 fs/read_write.c:1065 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 other info that might help us debug this: Chain exists of: &sig->cred_guard_mutex --> sb_writers#3 --> &p->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&p->lock); lock(sb_writers#3); lock(&p->lock); lock(&sig->cred_guard_mutex); *** DEADLOCK *** 1 lock held by syz-executor.5/15008: #0: (&p->lock){+.+.}, at: [] seq_read+0xba/0x1160 fs/seq_file.c:165 stack backtrace: CPU: 1 PID: 15008 Comm: syz-executor.5 Not tainted 4.14.177-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+0x13e/0x194 lib/dump_stack.c:58 print_circular_bug.isra.0.cold+0x1c4/0x282 kernel/locking/lockdep.c:1258 check_prev_add kernel/locking/lockdep.c:1905 [inline] check_prevs_add kernel/locking/lockdep.c:2022 [inline] validate_chain kernel/locking/lockdep.c:2464 [inline] __lock_acquire+0x2cb3/0x4620 kernel/locking/lockdep.c:3491 lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xe8/0x1470 kernel/locking/mutex.c:893 lock_trace+0x3f/0xc0 fs/proc/base.c:407 proc_pid_stack+0x10b/0x240 fs/proc/base.c:457 proc_single_show+0xe7/0x150 fs/proc/base.c:761 seq_read+0x4d2/0x1160 fs/seq_file.c:237 do_loop_readv_writev fs/read_write.c:695 [inline] do_loop_readv_writev fs/read_write.c:682 [inline] do_iter_read+0x3e3/0x5a0 fs/read_write.c:919 vfs_readv+0xd3/0x130 fs/read_write.c:981 do_preadv+0x161/0x200 fs/read_write.c:1065 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x45c829 RSP: 002b:00007f29047adc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 00000000004fa1c0 RCX: 000000000045c829 RDX: 000000000000037d RSI: 0000000020000500 RDI: 0000000000000004 RBP: 000000000078bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 000000000000085c R14: 00000000004cb1c7 R15: 00007f29047ae6d4 IPVS: persistence engine module ip_vs_pe_ ip not found kauditd_printk_skb: 21 callbacks suppressed audit: type=1800 audit(1587794663.496:789): pid=15115 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="collect_data" cause="failed(directio)" comm="syz-executor.4" name="bus" dev="sda1" ino=15874 res=0 audit: type=1800 audit(1587794663.506:790): pid=15122 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="collect_data" cause="failed(directio)" comm="syz-executor.2" name="bus" dev="sda1" ino=15891 res=0 audit: type=1800 audit(1587794663.756:791): pid=15147 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="collect_data" cause="failed(directio)" comm="syz-executor.2" name="bus" dev="sda1" ino=15862 res=0 audit: type=1800 audit(1587794663.786:792): pid=15149 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="collect_data" cause="failed(directio)" comm="syz-executor.5" name="bus" dev="sda1" ino=15873 res=0 audit: type=1800 audit(1587794663.786:793): pid=15148 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="collect_data" cause="failed(directio)" comm="syz-executor.4" name="bus" dev="sda1" ino=15874 res=0 audit: type=1800 audit(1587794663.806:794): pid=15152 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="collect_data" cause="failed(directio)" comm="syz-executor.1" name="bus" dev="sda1" ino=15786 res=0 audit: type=1800 audit(1587794663.896:795): pid=15164 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="collect_data" cause="failed(directio)" comm="syz-executor.5" name="bus" dev="sda1" ino=15873 res=0 netlink: 52 bytes leftover after parsing attributes in process `syz-executor.4'. ptrace attach of "/root/syz-executor.4"[15172] was attempted by "/root/syz-executor.4"[15176] audit: type=1800 audit(1587794664.026:796): pid=15180 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="collect_data" cause="failed(directio)" comm="syz-executor.2" name="bus" dev="sda1" ino=15956 res=0 IPVS: persistence engine module ip_vs_pe_ ip not found audit: type=1800 audit(1587794664.036:797): pid=15175 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="collect_data" cause="failed(directio)" comm="syz-executor.1" name="bus" dev="sda1" ino=15971 res=0 audit: type=1800 audit(1587794664.046:798): pid=15172 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="collect_data" cause="failed(directio)" comm="syz-executor.4" name="bus" dev="sda1" ino=15986 res=0 ptrace attach of "/root/syz-executor.4"[15226] was attempted by "/root/syz-executor.4"[15228] IPVS: persistence engine module ip_vs_pe_ ip not found IPVS: persistence engine module ip_vs_pe_ ip not found IPVS: persistence engine module ip_vs_pe_ ip not found ptrace attach of "/root/syz-executor.4"[15255] was attempted by "/root/syz-executor.4"[15256] IPVS: persistence engine module ip_vs_pe_ ip not found IPVS: persistence engine module ip_vs_pe_ ip not found IPVS: persistence engine module ip_vs_pe_ ip not found IPVS: persistence engine module ip_vs_pe_ ip not found IPVS: persistence engine module ip_vs_pe_ ip not found netlink: 52 bytes leftover after parsing attributes in process `syz-executor.0'. ptrace attach of "/root/syz-executor.0"[15336] was attempted by "/root/syz-executor.0"[15338] netlink: 52 bytes leftover after parsing attributes in process `syz-executor.0'. NOHZ: local_softirq_pending 08 NOHZ: local_softirq_pending 08 IPVS: persistence engine module ip_vs_pe_ ip not found IPVS: persistence engine module ip_vs_pe_ ip not found IPVS: persistence engine module ip_vs_pe_ ip not found IPVS: persistence engine module ip_vs_pe_ ip not found kauditd_printk_skb: 28 callbacks suppressed audit: type=1800 audit(1587794668.546:827): pid=15477 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="collect_data" cause="failed(directio)" comm="syz-executor.4" name="bus" dev="sda1" ino=15890 res=0 IPVS: persistence engine module ip_vs_pe_ ip not found audit: type=1800 audit(1587794668.586:828): pid=15480 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="collect_data" cause="failed(directio)" comm="syz-executor.0" name="bus" dev="sda1" ino=15785 res=0 IPVS: persistence engine module ip_vs_pe_ ip not found audit: type=1800 audit(1587794668.986:829): pid=15516 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="collect_data" cause="failed(directio)" comm="syz-executor.0" name="bus" dev="sda1" ino=15820 res=0 IPVS: persistence engine module ip_vs_pe_ ip not found IPVS: persistence engine module ip_vs_pe_ ip not found audit: type=1800 audit(1587794669.486:830): pid=15561 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="collect_data" cause="failed(directio)" comm="syz-executor.4" name="bus" dev="sda1" ino=16001 res=0 netlink: 40 bytes leftover after parsing attributes in process `syz-executor.0'. audit: type=1800 audit(1587794670.006:831): pid=15607 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="collect_data" cause="failed(directio)" comm="syz-executor.0" name="bus" dev="sda1" ino=16097 res=0 audit: type=1800 audit(1587794670.236:832): pid=15632 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="collect_data" cause="failed(directio)" comm="syz-executor.0" name="bus" dev="sda1" ino=15792 res=0 IPVS: persistence engine module ip_vs_pe_ ip not found