audit: type=1401 audit(1546899258.623:34): op=fscreate invalid_context=40010020D10000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000617474722F66736372656174650000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000073797A33000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000CC6F871D907E97C4AFBFF1 ====================================================== [ INFO: possible circular locking dependency detected ] 4.4.169+ #2 Not tainted ------------------------------------------------------- syz-executor5/5700 is trying to acquire lock: (&sig->cred_guard_mutex){+.+.+.}, at: [] lock_trace+0x44/0xc0 fs/proc/base.c:448 but task is already holding lock: (&p->lock){+.+.+.}, at: [] seq_read+0xd6/0x1240 fs/seq_file.c:178 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: [] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592 [] __mutex_lock_common kernel/locking/mutex.c:521 [inline] [] mutex_lock_nested+0xc1/0xb80 kernel/locking/mutex.c:621 [] seq_read+0xd6/0x1240 fs/seq_file.c:178 [] proc_reg_read+0xfd/0x180 fs/proc/inode.c:202 [] do_loop_readv_writev+0x148/0x1e0 fs/read_write.c:680 [] do_readv_writev+0x573/0x6e0 fs/read_write.c:810 [] vfs_readv+0x7a/0xb0 fs/read_write.c:834 [] kernel_readv fs/splice.c:586 [inline] [] default_file_splice_read+0x3ac/0x8b0 fs/splice.c:662 [] do_splice_to+0xff/0x160 fs/splice.c:1154 [] splice_direct_to_actor+0x249/0x850 fs/splice.c:1226 [] do_splice_direct+0x1a5/0x260 fs/splice.c:1337 [] do_sendfile+0x4ed/0xba0 fs/read_write.c:1227 [] C_SYSC_sendfile fs/read_write.c:1309 [inline] [] compat_SyS_sendfile+0x144/0x160 fs/read_write.c:1292 [] do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline] [] do_fast_syscall_32+0x32d/0xa90 arch/x86/entry/common.c:397 [] sysenter_flags_fixed+0xd/0x1a [] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592 [] percpu_down_read include/linux/percpu-rwsem.h:26 [inline] [] __sb_start_write+0x1af/0x310 fs/super.c:1221 [] sb_start_write include/linux/fs.h:1517 [inline] [] ext4_run_li_request fs/ext4/super.c:2674 [inline] [] ext4_lazyinit_thread fs/ext4/super.c:2773 [inline] [] ext4_lazyinit_thread+0x1e4/0x7b0 fs/ext4/super.c:2749 [] kthread+0x273/0x310 kernel/kthread.c:211 [] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:537 [] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592 [] __mutex_lock_common kernel/locking/mutex.c:521 [inline] [] mutex_lock_nested+0xc1/0xb80 kernel/locking/mutex.c:621 [] ext4_register_li_request+0x2fd/0x7d0 fs/ext4/super.c:2961 [] ext4_remount+0x1366/0x1b90 fs/ext4/super.c:4911 [] do_remount_sb2+0x41b/0x7a0 fs/super.c:771 [] do_remount fs/namespace.c:2347 [inline] [] do_mount+0xfdb/0x2a40 fs/namespace.c:2860 [] SYSC_mount fs/namespace.c:3063 [inline] [] SyS_mount+0x130/0x1d0 fs/namespace.c:3041 [] entry_SYSCALL_64_fastpath+0x1e/0x9a [] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592 [] __mutex_lock_common kernel/locking/mutex.c:521 [inline] [] mutex_lock_nested+0xc1/0xb80 kernel/locking/mutex.c:621 [] ext4_register_li_request+0x89/0x7d0 fs/ext4/super.c:2934 [] ext4_remount+0x1366/0x1b90 fs/ext4/super.c:4911 [] do_remount_sb2+0x41b/0x7a0 fs/super.c:771 [] do_remount fs/namespace.c:2347 [inline] [] do_mount+0xfdb/0x2a40 fs/namespace.c:2860 [] SYSC_mount fs/namespace.c:3063 [inline] [] SyS_mount+0x130/0x1d0 fs/namespace.c:3041 [] entry_SYSCALL_64_fastpath+0x1e/0x9a [] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592 [] down_read+0x42/0x60 kernel/locking/rwsem.c:22 [] iterate_supers+0xe1/0x250 fs/super.c:537 [] selinux_complete_init+0x2f/0x31 security/selinux/hooks.c:6154 [] security_load_policy+0x69d/0x9c0 security/selinux/ss/services.c:2060 [] sel_write_load+0x175/0xf90 security/selinux/selinuxfs.c:535 [] __vfs_write+0x116/0x3d0 fs/read_write.c:489 [] vfs_write+0x182/0x4e0 fs/read_write.c:538 [] SYSC_write fs/read_write.c:585 [inline] [] SyS_write+0xdc/0x1c0 fs/read_write.c:577 [] entry_SYSCALL_64_fastpath+0x1e/0x9a [] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592 [] __mutex_lock_common kernel/locking/mutex.c:521 [inline] [] mutex_lock_nested+0xc1/0xb80 kernel/locking/mutex.c:621 [] sel_commit_bools_write+0x89/0x260 security/selinux/selinuxfs.c:1142 [] __vfs_write+0x116/0x3d0 fs/read_write.c:489 [] __kernel_write+0x112/0x370 fs/read_write.c:511 [] write_pipe_buf+0x15d/0x1f0 fs/splice.c:1074 [] splice_from_pipe_feed fs/splice.c:776 [inline] [] __splice_from_pipe+0x37e/0x7a0 fs/splice.c:901 [] splice_from_pipe+0x108/0x170 fs/splice.c:936 [] default_file_splice_write+0x3c/0x80 fs/splice.c:1086 [] do_splice_from fs/splice.c:1128 [inline] [] do_splice fs/splice.c:1404 [inline] [] SYSC_splice fs/splice.c:1707 [inline] [] SyS_splice+0xd71/0x13a0 fs/splice.c:1690 [] do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline] [] do_fast_syscall_32+0x32d/0xa90 arch/x86/entry/common.c:397 [] sysenter_flags_fixed+0xd/0x1a [] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592 [] __mutex_lock_common kernel/locking/mutex.c:521 [inline] [] mutex_lock_nested+0xc1/0xb80 kernel/locking/mutex.c:621 [] __pipe_lock fs/pipe.c:86 [inline] [] fifo_open+0x15d/0xa00 fs/pipe.c:896 [] do_dentry_open+0x38f/0xbd0 fs/open.c:749 [] vfs_open+0x10b/0x210 fs/open.c:862 [] do_last fs/namei.c:3269 [inline] [] path_openat+0x136f/0x4470 fs/namei.c:3406 [] do_filp_open+0x1a1/0x270 fs/namei.c:3440 [] do_open_execat+0x10c/0x6e0 fs/exec.c:805 [] do_execveat_common.isra.0+0x6f6/0x1e90 fs/exec.c:1577 [] compat_do_execve fs/exec.c:1710 [inline] [] C_SYSC_execve fs/exec.c:1785 [inline] [] compat_SyS_execve+0x48/0x60 fs/exec.c:1781 [] do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline] [] do_fast_syscall_32+0x32d/0xa90 arch/x86/entry/common.c:397 [] sysenter_flags_fixed+0xd/0x1a [] check_prev_add kernel/locking/lockdep.c:1853 [inline] [] check_prevs_add kernel/locking/lockdep.c:1958 [inline] [] validate_chain kernel/locking/lockdep.c:2144 [inline] [] __lock_acquire+0x37d6/0x4f50 kernel/locking/lockdep.c:3213 [] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592 [] __mutex_lock_common kernel/locking/mutex.c:521 [inline] [] mutex_lock_killable_nested+0xd2/0xd00 kernel/locking/mutex.c:641 [] lock_trace+0x44/0xc0 fs/proc/base.c:448 [] proc_pid_syscall+0x9b/0x250 fs/proc/base.c:683 [] proc_single_show+0xf6/0x160 fs/proc/base.c:805 [] seq_read+0x4cd/0x1240 fs/seq_file.c:240 [] do_loop_readv_writev+0x148/0x1e0 fs/read_write.c:680 [] do_readv_writev+0x573/0x6e0 fs/read_write.c:810 [] vfs_readv+0x7a/0xb0 fs/read_write.c:834 [] kernel_readv fs/splice.c:586 [inline] [] default_file_splice_read+0x3ac/0x8b0 fs/splice.c:662 [] do_splice_to+0xff/0x160 fs/splice.c:1154 [] splice_direct_to_actor+0x249/0x850 fs/splice.c:1226 [] do_splice_direct+0x1a5/0x260 fs/splice.c:1337 [] do_sendfile+0x4ed/0xba0 fs/read_write.c:1227 [] C_SYSC_sendfile fs/read_write.c:1309 [inline] [] compat_SyS_sendfile+0x144/0x160 fs/read_write.c:1292 [] do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline] [] do_fast_syscall_32+0x32d/0xa90 arch/x86/entry/common.c:397 [] sysenter_flags_fixed+0xd/0x1a other info that might help us debug this: Chain exists of: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&p->lock); lock(sb_writers#4); lock(&p->lock); lock(&sig->cred_guard_mutex); *** DEADLOCK *** 2 locks held by syz-executor5/5700: #0: (sb_writers#7){.+.+.+}, at: [] file_start_write include/linux/fs.h:2543 [inline] #0: (sb_writers#7){.+.+.+}, at: [] do_sendfile+0x8a6/0xba0 fs/read_write.c:1226 #1: (&p->lock){+.+.+.}, at: [] seq_read+0xd6/0x1240 fs/seq_file.c:178 stack backtrace: CPU: 0 PID: 5700 Comm: syz-executor5 Not tainted 4.4.169+ #2 0000000000000000 7ccaf0ec93835b3c ffff8801d1456d40 ffffffff81aab9c1 ffffffff84055ac0 ffff8800b3202f80 ffffffff83ab4860 ffffffff83ab61b0 ffffffff83aba380 ffff8801d1456d90 ffffffff813abaf4 ffffffff83e28400 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x120 lib/dump_stack.c:51 [] print_circular_bug.cold+0x2f7/0x44e kernel/locking/lockdep.c:1226 [] check_prev_add kernel/locking/lockdep.c:1853 [inline] [] check_prevs_add kernel/locking/lockdep.c:1958 [inline] [] validate_chain kernel/locking/lockdep.c:2144 [inline] [] __lock_acquire+0x37d6/0x4f50 kernel/locking/lockdep.c:3213 [] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592 [] __mutex_lock_common kernel/locking/mutex.c:521 [inline] [] mutex_lock_killable_nested+0xd2/0xd00 kernel/locking/mutex.c:641 [] lock_trace+0x44/0xc0 fs/proc/base.c:448 [] proc_pid_syscall+0x9b/0x250 fs/proc/base.c:683 [] proc_single_show+0xf6/0x160 fs/proc/base.c:805 [] seq_read+0x4cd/0x1240 fs/seq_file.c:240 [] do_loop_readv_writev+0x148/0x1e0 fs/read_write.c:680 [] do_readv_writev+0x573/0x6e0 fs/read_write.c:810 [] vfs_readv+0x7a/0xb0 fs/read_write.c:834 [] kernel_readv fs/splice.c:586 [inline] [] default_file_splice_read+0x3ac/0x8b0 fs/splice.c:662 [] do_splice_to+0xff/0x160 fs/splice.c:1154 [] splice_direct_to_actor+0x249/0x850 fs/splice.c:1226 [] do_splice_direct+0x1a5/0x260 fs/splice.c:1337 [] do_sendfile+0x4ed/0xba0 fs/read_write.c:1227 [] C_SYSC_sendfile fs/read_write.c:1309 [inline] [] compat_SyS_sendfile+0x144/0x160 fs/read_write.c:1292 [] do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline] [] do_fast_syscall_32+0x32d/0xa90 arch/x86/entry/common.c:397 [] sysenter_flags_fixed+0xd/0x1a