overlayfs: './file0' not a directory ====================================================== WARNING: possible circular locking dependency detected 5.6.0-rc5-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.3/11170 is trying to acquire lock: ffff888097db9c50 (&sig->cred_guard_mutex){+.+.}, at: lock_trace+0x45/0xe0 fs/proc/base.c:408 but task is already holding lock: ffff8880913eebe0 (&p->lock){+.+.}, at: seq_read+0x6b/0x1160 fs/seq_file.c:161 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:956 [inline] __mutex_lock+0x156/0x13c0 kernel/locking/mutex.c:1103 seq_read+0x6b/0x1160 fs/seq_file.c:161 do_loop_readv_writev fs/read_write.c:714 [inline] do_loop_readv_writev fs/read_write.c:701 [inline] do_iter_read+0x47f/0x650 fs/read_write.c:935 vfs_readv+0xf0/0x160 fs/read_write.c:1053 kernel_readv fs/splice.c:365 [inline] default_file_splice_read+0x4fb/0xa20 fs/splice.c:422 do_splice_to+0x10e/0x160 fs/splice.c:892 splice_direct_to_actor+0x307/0x980 fs/splice.c:971 do_splice_direct+0x1a8/0x270 fs/splice.c:1080 do_sendfile+0x549/0xc40 fs/read_write.c:1520 __do_sys_sendfile64 fs/read_write.c:1581 [inline] __se_sys_sendfile64 fs/read_write.c:1567 [inline] __x64_sys_sendfile64+0x1cc/0x210 fs/read_write.c:1567 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #2 (sb_writers#4){.+.+}: percpu_down_read include/linux/percpu-rwsem.h:40 [inline] __sb_start_write+0x21b/0x430 fs/super.c:1674 sb_start_write include/linux/fs.h:1650 [inline] mnt_want_write+0x3a/0xb0 fs/namespace.c:354 ovl_setattr+0xdd/0x8b0 fs/overlayfs/inode.c:27 notify_change+0xb6d/0x1060 fs/attr.c:336 do_truncate+0x134/0x1f0 fs/open.c:64 handle_truncate fs/namei.c:3083 [inline] do_last fs/namei.c:3496 [inline] path_openat+0x291f/0x32b0 fs/namei.c:3607 do_filp_open+0x192/0x260 fs/namei.c:3637 do_sys_openat2+0x54c/0x740 fs/open.c:1146 do_sys_open+0xc3/0x140 fs/open.c:1162 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #1 (&ovl_i_mutex_key[depth]){+.+.}: down_write+0x8d/0x150 kernel/locking/rwsem.c:1534 inode_lock include/linux/fs.h:792 [inline] process_measurement+0x68a/0x1740 security/integrity/ima/ima_main.c:230 ima_file_check+0xb9/0x100 security/integrity/ima/ima_main.c:442 do_last fs/namei.c:3494 [inline] path_openat+0x127f/0x32b0 fs/namei.c:3607 do_filp_open+0x192/0x260 fs/namei.c:3637 do_open_execat+0x122/0x600 fs/exec.c:860 __do_execve_file.isra.0+0x16d5/0x2270 fs/exec.c:1765 do_execveat_common fs/exec.c:1871 [inline] do_execve fs/exec.c:1888 [inline] __do_sys_execve fs/exec.c:1964 [inline] __se_sys_execve fs/exec.c:1959 [inline] __x64_sys_execve+0x8a/0xb0 fs/exec.c:1959 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (&sig->cred_guard_mutex){+.+.}: check_prev_add kernel/locking/lockdep.c:2475 [inline] check_prevs_add kernel/locking/lockdep.c:2580 [inline] validate_chain kernel/locking/lockdep.c:2970 [inline] __lock_acquire+0x201b/0x3ca0 kernel/locking/lockdep.c:3954 lock_acquire+0x197/0x420 kernel/locking/lockdep.c:4484 __mutex_lock_common kernel/locking/mutex.c:956 [inline] __mutex_lock+0x156/0x13c0 kernel/locking/mutex.c:1103 lock_trace+0x45/0xe0 fs/proc/base.c:408 proc_pid_personality+0x17/0xc0 fs/proc/base.c:3052 proc_single_show+0xf7/0x1c0 fs/proc/base.c:758 seq_read+0x4b9/0x1160 fs/seq_file.c:229 do_loop_readv_writev fs/read_write.c:714 [inline] do_loop_readv_writev fs/read_write.c:701 [inline] do_iter_read+0x47f/0x650 fs/read_write.c:935 vfs_readv+0xf0/0x160 fs/read_write.c:1053 kernel_readv fs/splice.c:365 [inline] default_file_splice_read+0x4fb/0xa20 fs/splice.c:422 do_splice_to+0x10e/0x160 fs/splice.c:892 splice_direct_to_actor+0x307/0x980 fs/splice.c:971 do_splice_direct+0x1a8/0x270 fs/splice.c:1080 do_sendfile+0x549/0xc40 fs/read_write.c:1520 __do_sys_sendfile64 fs/read_write.c:1581 [inline] __se_sys_sendfile64 fs/read_write.c:1567 [inline] __x64_sys_sendfile64+0x1cc/0x210 fs/read_write.c:1567 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: Chain exists of: &sig->cred_guard_mutex --> sb_writers#4 --> &p->lock 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-executor.3/11170: #0: ffff88809fa24428 (sb_writers#13){.+.+}, at: file_start_write include/linux/fs.h:2904 [inline] #0: ffff88809fa24428 (sb_writers#13){.+.+}, at: do_sendfile+0x939/0xc40 fs/read_write.c:1519 #1: ffff8880913eebe0 (&p->lock){+.+.}, at: seq_read+0x6b/0x1160 fs/seq_file.c:161 stack backtrace: CPU: 0 PID: 11170 Comm: syz-executor.3 Not tainted 5.6.0-rc5-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+0x188/0x20d lib/dump_stack.c:118 check_noncircular+0x32e/0x3e0 kernel/locking/lockdep.c:1808 check_prev_add kernel/locking/lockdep.c:2475 [inline] check_prevs_add kernel/locking/lockdep.c:2580 [inline] validate_chain kernel/locking/lockdep.c:2970 [inline] __lock_acquire+0x201b/0x3ca0 kernel/locking/lockdep.c:3954 lock_acqu