overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir ====================================================== WARNING: possible circular locking dependency detected 4.19.107-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.2/17698 is trying to acquire lock: 00000000484cda04 (sb_writers#4){.+.+}, at: sb_start_write include/linux/fs.h:1578 [inline] 00000000484cda04 (sb_writers#4){.+.+}, at: mnt_want_write+0x3a/0xb0 fs/namespace.c:360 but task is already holding lock: 00000000b5228392 (&ovl_i_mutex_dir_key[depth]){++++}, at: inode_lock include/linux/fs.h:747 [inline] 00000000b5228392 (&ovl_i_mutex_dir_key[depth]){++++}, at: vfs_setxattr+0x92/0xf0 fs/xattr.c:218 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&ovl_i_mutex_dir_key[depth]){++++}: inode_lock_shared include/linux/fs.h:757 [inline] do_last fs/namei.c:3326 [inline] path_openat+0x1d18/0x4200 fs/namei.c:3537 do_filp_open+0x1a1/0x280 fs/namei.c:3567 do_open_execat+0x124/0x5b0 fs/exec.c:853 __do_execve_file.isra.0+0x1577/0x2110 fs/exec.c:1755 do_execveat_common fs/exec.c:1866 [inline] do_execve fs/exec.c:1883 [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+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #2 (&sig->cred_guard_mutex){+.+.}: do_io_accounting+0x1da/0x7b0 fs/proc/base.c:2738 proc_single_show+0xeb/0x170 fs/proc/base.c:755 seq_read+0x4b9/0x10f0 fs/seq_file.c:229 do_loop_readv_writev fs/read_write.c:701 [inline] do_loop_readv_writev fs/read_write.c:688 [inline] do_iter_read+0x46b/0x640 fs/read_write.c:925 vfs_readv+0xf0/0x160 fs/read_write.c:987 do_preadv+0x1b6/0x270 fs/read_write.c:1071 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #1 (&p->lock){+.+.}: seq_read+0x6b/0x10f0 fs/seq_file.c:161 do_loop_readv_writev fs/read_write.c:701 [inline] do_loop_readv_writev fs/read_write.c:688 [inline] do_iter_read+0x46b/0x640 fs/read_write.c:925 vfs_readv+0xf0/0x160 fs/read_write.c:987 kernel_readv fs/splice.c:362 [inline] default_file_splice_read+0x478/0x970 fs/splice.c:417 do_splice_to+0x10e/0x160 fs/splice.c:881 splice_direct_to_actor+0x2b9/0x8d0 fs/splice.c:959 do_splice_direct+0x1a8/0x270 fs/splice.c:1068 do_sendfile+0x549/0xc10 fs/read_write.c:1447 __do_sys_sendfile64 fs/read_write.c:1508 [inline] __se_sys_sendfile64 fs/read_write.c:1494 [inline] __x64_sys_sendfile64+0x1cc/0x210 fs/read_write.c:1494 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (sb_writers#4){.+.+}: 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+0x1e6/0x340 fs/super.c:1387 sb_start_write include/linux/fs.h:1578 [inline] mnt_want_write+0x3a/0xb0 fs/namespace.c:360 ovl_xattr_set+0x53/0x5a0 fs/overlayfs/inode.c:338 __vfs_setxattr+0x10e/0x170 fs/xattr.c:149 __vfs_setxattr_noperm+0x11a/0x410 fs/xattr.c:180 vfs_setxattr+0xd2/0xf0 fs/xattr.c:223 setxattr+0x23d/0x330 fs/xattr.c:450 path_setxattr+0x170/0x190 fs/xattr.c:469 __do_sys_lsetxattr fs/xattr.c:491 [inline] __se_sys_lsetxattr fs/xattr.c:487 [inline] __x64_sys_lsetxattr+0xbd/0x150 fs/xattr.c:487 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: Chain exists of: sb_writers#4 --> &sig->cred_guard_mutex --> &ovl_i_mutex_dir_key[depth] Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&ovl_i_mutex_dir_key[depth]); lock(&sig->cred_guard_mutex); lock(&ovl_i_mutex_dir_key[depth]); lock(sb_writers#4); *** DEADLOCK *** 2 locks held by syz-executor.2/17698: #0: 0000000094da3619 (sb_writers#13){.+.+}, at: sb_start_write include/linux/fs.h:1578 [inline] #0: 0000000094da3619 (sb_writers#13){.+.+}, at: mnt_want_write+0x3a/0xb0 fs/namespace.c:360 #1: 00000000b5228392 (&ovl_i_mutex_dir_key[depth]){++++}, at: inode_lock include/linux/fs.h:747 [inline] #1: 00000000b5228392 (&ovl_i_mutex_dir_key[depth]){++++}, at: vfs_setxattr+0x92/0xf0 fs/xattr.c:218 stack backtrace: CPU: 1 PID: 17698 Comm: syz-executor.2 Not tainted 4.19.107-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 print_circular_bug.isra.0.cold+0x1c4/0x282 kernel/locking/lockdep.c:1221 check_prev_add kernel/locking/lockdep.c:1861 [inline] check_prevs_add kernel/locking/lockdep.c:1974 [inline] validate_chain kernel/locking/lockdep.c:2415 [inline] __lock_acquire+0x2e19/0x49c0 kernel/locking/lockdep.c:3411 lock_acquire+0x170/0x400 kernel/locking/lockdep.c:3903 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+0x1e6/0x340 fs/super.c:1387 sb_start_write include/linux/fs.h:1578 [inline] mnt_want_write+0x3a/0xb0 fs/namespace.c:360 ovl_xattr_set+0x53/0x5a0 fs/overlayfs/inode.c:338 __vfs_setxattr+0x10e/0x170 fs/xattr.c:149 __vfs_setxattr_noperm+0x11a/0x410 fs/xattr.c:180 vfs_setxattr+0xd2/0xf0 fs/xattr.c:223 setxattr+0x23d/0x330 fs/xattr.c:450 path_setxattr+0x170/0x190 fs/xattr.c:469 __do_sys_lsetxattr fs/xattr.c:491 [inline] __se_sys_lsetxattr fs/xattr.c:487 [inline] __x64_sys_lsetxattr+0xbd/0x150 fs/xattr.c:487 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c479 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f409090cc78 EFLAGS: 00000246 ORIG_RAX: 00000000000000bd RAX: ffffffffffffffda RBX: 00007f409090d6d4 RCX: 000000000045c479 RDX: 0000000000000000 RSI: 0000000020000200 RDI: 0000000020000140 RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 000000000000071a R14: 00000000004c9a45 R15: 000000000076bf2c overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: failed to resolve 'file0': -2 overlayfs: failed to resolve 'file0': -2 overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: failed to resolve 'file0': -2 overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: failed to resolve 'file0': -2 overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: failed to resolve 'file0': -2 overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: failed to resolve 'file0': -2 overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: failed to resolve 'file0': -2 overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: failed to resolve 'file0': -2 overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: failed to resolve 'file0': -2 overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: './bus' not a directory overlayfs: failed to resolve 'file0': -2 overlayfs: filesystem on './file0' not supported as upperdir overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: failed to resolve 'file0': -2 overlayfs: filesystem on './file0' not supported as upperdir overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: failed to resolve 'file0': -2 overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: failed to resolve 'file0': -2 overlayfs: filesystem on './file0' not supported as upperdir overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: failed to resolve 'file0': -2 overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: failed to resolve 'file0': -2 overlayfs: filesystem on './file0' not supported as upperdir overlayfs: failed to resolve 'file0': -2 overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: failed to resolve 'file0': -2 overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: failed to resolve 'file0': -2 overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: failed to resolve 'file0': -2 overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir overlayfs: './bus' not a directory overlayfs: filesystem on './file0' not supported as upperdir overlayfs: filesystem on './file0' not supported as upperdir