====================================================== WARNING: possible circular locking dependency detected 5.2.0-next-20190710 #35 Not tainted ------------------------------------------------------ syz-executor.5/9162 is trying to acquire lock: 0000000039fb6065 (rename_lock#2){+.+.}, at: shrink_dcache_parent+0xb7/0x430 fs/dcache.c:1544 but task is already holding lock: 0000000016a081b6 (&(&dentry->d_lockref.lock)->rlock){+.+.}, at: spin_lock include/linux/spinlock.h:338 [inline] 0000000016a081b6 (&(&dentry->d_lockref.lock)->rlock){+.+.}, at: shrink_dcache_parent+0x134/0x430 fs/dcache.c:1558 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&(&dentry->d_lockref.lock)->rlock){+.+.}: __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] d_set_mounted+0x17e/0x2e0 fs/dcache.c:1434 get_mountpoint+0x166/0x3f0 fs/namespace.c:724 lock_mount+0xf1/0x2e0 fs/namespace.c:2131 do_add_mount+0x27/0x380 fs/namespace.c:2669 do_new_mount_fc fs/namespace.c:2730 [inline] do_new_mount fs/namespace.c:2785 [inline] do_mount+0x178f/0x1c30 fs/namespace.c:3103 ksys_mount+0xdb/0x150 fs/namespace.c:3312 devtmpfsd+0xbd/0x130 drivers/base/devtmpfs.c:397 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 -> #0 (rename_lock#2){+.+.}: check_prev_add kernel/locking/lockdep.c:2405 [inline] check_prevs_add kernel/locking/lockdep.c:2507 [inline] validate_chain kernel/locking/lockdep.c:2897 [inline] __lock_acquire+0x25a9/0x4c30 kernel/locking/lockdep.c:3880 lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4413 seqcount_lockdep_reader_access include/linux/seqlock.h:81 [inline] read_seqcount_begin include/linux/seqlock.h:164 [inline] read_seqbegin include/linux/seqlock.h:433 [inline] read_seqbegin_or_lock include/linux/seqlock.h:529 [inline] d_walk+0xe8/0x950 fs/dcache.c:1277 shrink_dcache_parent+0xb7/0x430 fs/dcache.c:1544 vfs_rmdir fs/namei.c:3882 [inline] vfs_rmdir+0x26f/0x4f0 fs/namei.c:3857 do_rmdir+0x39e/0x420 fs/namei.c:3940 __do_sys_rmdir fs/namei.c:3958 [inline] __se_sys_rmdir fs/namei.c:3956 [inline] __x64_sys_rmdir+0x36/0x40 fs/namei.c:3956 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&(&dentry->d_lockref.lock)->rlock); lock(rename_lock#2); lock(&(&dentry->d_lockref.lock)->rlock); lock(rename_lock#2); *** DEADLOCK *** 4 locks held by syz-executor.5/9162: #0: 0000000064353482 (sb_writers#3){.+.+}, at: sb_start_write include/linux/fs.h:1625 [inline] #0: 0000000064353482 (sb_writers#3){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:354 #1: 0000000061b5f5fe (&type->i_mutex_dir_key#3/1){+.+.}, at: inode_lock_nested include/linux/fs.h:813 [inline] #1: 0000000061b5f5fe (&type->i_mutex_dir_key#3/1){+.+.}, at: do_rmdir+0x271/0x420 fs/namei.c:3928 #2: 00000000ba279aa1 (&type->i_mutex_dir_key#3){++++}, at: inode_lock include/linux/fs.h:778 [inline] #2: 00000000ba279aa1 (&type->i_mutex_dir_key#3){++++}, at: vfs_rmdir fs/namei.c:3868 [inline] #2: 00000000ba279aa1 (&type->i_mutex_dir_key#3){++++}, at: vfs_rmdir+0xe5/0x4f0 fs/namei.c:3857 #3: 0000000016a081b6 (&(&dentry->d_lockref.lock)->rlock){+.+.}, at: spin_lock include/linux/spinlock.h:338 [inline] #3: 0000000016a081b6 (&(&dentry->d_lockref.lock)->rlock){+.+.}, at: shrink_dcache_parent+0x134/0x430 fs/dcache.c:1558 stack backtrace: CPU: 1 PID: 9162 Comm: syz-executor.5 Not tainted 5.2.0-next-20190710 #35 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+0x172/0x1f0 lib/dump_stack.c:113 print_circular_bug.cold+0x163/0x172 kernel/locking/lockdep.c:1617 check_noncircular+0x345/0x3e0 kernel/locking/lockdep.c:1741 check_prev_add kernel/locking/lockdep.c:2405 [inline] check_prevs_add kernel/locking/lockdep.c:2507 [inline] validate_chain kernel/locking/lockdep.c:2897 [inline] __lock_acquire+0x25a9/0x4c30 kernel/locking/lockdep.c:3880 lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4413 seqcount_lockdep_reader_access include/linux/seqlock.h:81 [inline] read_seqcount_begin include/linux/seqlock.h:164 [inline] read_seqbegin include/linux/seqlock.h:433 [inline] read_seqbegin_or_lock include/linux/seqlock.h:529 [inline] d_walk+0xe8/0x950 fs/dcache.c:1277 shrink_dcache_parent+0xb7/0x430 fs/dcache.c:1544 vfs_rmdir fs/namei.c:3882 [inline] vfs_rmdir+0x26f/0x4f0 fs/namei.c:3857 do_rmdir+0x39e/0x420 fs/namei.c:3940 __do_sys_rmdir fs/namei.c:3958 [inline] __se_sys_rmdir fs/namei.c:3956 [inline] __x64_sys_rmdir+0x36/0x40 fs/namei.c:3956 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459537 Code: 00 66 90 b8 57 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 7d ba fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 54 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 5d ba fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fff83167188 EFLAGS: 00000207 ORIG_RAX: 0000000000000054 RAX: ffffffffffffffda RBX: 0000000000000065 RCX: 0000000000459537 RDX: 0000000000000000 RSI: 0000000000714698 RDI: 00007fff831682c0 RBP: 0000000000000340 R08: 0000000000000000 R09: 0000000000000001 R10: 000000000000000a R11: 0000000000000207 R12: 00007fff831682c0 R13: 000055555604a940 R14: 0000000000000000 R15: 00007fff831682c0 BUG: sleeping function called from invalid context at fs/dcache.c:1551 in_atomic(): 1, irqs_disabled(): 0, pid: 9162, name: syz-executor.5 INFO: lockdep is turned off. Preemption disabled at: [] spin_lock include/linux/spinlock.h:338 [inline] [] shrink_dcache_parent+0x134/0x430 fs/dcache.c:1558 CPU: 1 PID: 9162 Comm: syz-executor.5 Not tainted 5.2.0-next-20190710 #35 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+0x172/0x1f0 lib/dump_stack.c:113 ___might_sleep.cold+0x1be/0x1f7 kernel/sched/core.c:6603 shrink_dcache_parent+0xdc/0x430 fs/dcache.c:1551 vfs_rmdir fs/namei.c:3882 [inline] vfs_rmdir+0x26f/0x4f0 fs/namei.c:3857 do_rmdir+0x39e/0x420 fs/namei.c:3940 __do_sys_rmdir fs/namei.c:3958 [inline] __se_sys_rmdir fs/namei.c:3956 [inline] __x64_sys_rmdir+0x36/0x40 fs/namei.c:3956 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459537 Code: 00 66 90 b8 57 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 7d ba fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 54 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 5d ba fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fff83167188 EFLAGS: 00000207 ORIG_RAX: 0000000000000054 RAX: ffffffffffffffda RBX: 0000000000000065 RCX: 0000000000459537 RDX: 0000000000000000 RSI: 0000000000714698 RDI: 00007fff831682c0 RBP: 0000000000000340 R08: 0000000000000000 R09: 0000000000000001 R10: 000000000000000a R11: 0000000000000207 R12: 00007fff831682c0 R13: 000055555604a940 R14: 0000000000000000 R15: 00007fff831682c0 BUG: scheduling while atomic: syz-executor.5/9162/0x00000002 INFO: lockdep is turned off. Modules linked in: Preemption disabled at: [] spin_lock include/linux/spinlock.h:338 [inline] [] shrink_dcache_parent+0x134/0x430 fs/dcache.c:1558