====================================================== WARNING: possible circular locking dependency detected 6.7.0-rc7-syzkaller-00016-gf5837722ffec #0 Not tainted ------------------------------------------------------ syz-executor.2/10806 is trying to acquire lock: ffff88807d194418 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:404 but task is already holding lock: ffff88807d9caff0 (&ovl_i_mutex_dir_key[depth]){++++}-{3:3}, at: inode_lock include/linux/fs.h:802 [inline] ffff88807d9caff0 (&ovl_i_mutex_dir_key[depth]){++++}-{3:3}, at: open_last_lookups fs/namei.c:3543 [inline] ffff88807d9caff0 (&ovl_i_mutex_dir_key[depth]){++++}-{3:3}, at: path_openat+0x7bc/0x3290 fs/namei.c:3776 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&ovl_i_mutex_dir_key[depth]){++++}-{3:3}: lock_acquire+0x1e3/0x530 kernel/locking/lockdep.c:5754 down_read+0xb1/0xa40 kernel/locking/rwsem.c:1526 inode_lock_shared include/linux/fs.h:812 [inline] lookup_slow+0x45/0x70 fs/namei.c:1710 walk_component+0x2d0/0x400 fs/namei.c:2002 lookup_last fs/namei.c:2459 [inline] path_lookupat+0x16f/0x450 fs/namei.c:2483 filename_lookup+0x255/0x610 fs/namei.c:2512 kern_path+0x35/0x50 fs/namei.c:2610 lookup_bdev+0xc5/0x290 block/bdev.c:979 resume_store+0x1a0/0x710 kernel/power/hibernate.c:1177 kernfs_fop_write_iter+0x3b3/0x510 fs/kernfs/file.c:334 do_iter_readv_writev+0x330/0x4a0 do_iter_write+0x1f6/0x8d0 fs/read_write.c:860 iter_file_splice_write+0x86d/0x1010 fs/splice.c:736 do_splice_from fs/splice.c:933 [inline] direct_splice_actor+0xea/0x1c0 fs/splice.c:1142 splice_direct_to_actor+0x376/0x9e0 fs/splice.c:1088 do_splice_direct+0x2ac/0x3f0 fs/splice.c:1194 do_sendfile+0x62c/0x1000 fs/read_write.c:1254 __do_sys_sendfile64 fs/read_write.c:1322 [inline] __se_sys_sendfile64+0x17c/0x1e0 fs/read_write.c:1308 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x45/0x110 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b -> #2 (&of->mutex){+.+.}-{3:3}: lock_acquire+0x1e3/0x530 kernel/locking/lockdep.c:5754 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x136/0xd60 kernel/locking/mutex.c:747 kernfs_seq_start+0x53/0x3a0 fs/kernfs/file.c:154 seq_read_iter+0x3d4/0xd10 fs/seq_file.c:225 call_read_iter include/linux/fs.h:2014 [inline] new_sync_read fs/read_write.c:389 [inline] vfs_read+0x78b/0xb00 fs/read_write.c:470 ksys_read+0x1a0/0x2c0 fs/read_write.c:613 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x45/0x110 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b -> #1 (&p->lock){+.+.}-{3:3}: lock_acquire+0x1e3/0x530 kernel/locking/lockdep.c:5754 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x136/0xd60 kernel/locking/mutex.c:747 seq_read_iter+0xb2/0xd10 fs/seq_file.c:182 proc_reg_read_iter+0x1bc/0x290 fs/proc/inode.c:302 call_read_iter include/linux/fs.h:2014 [inline] copy_splice_read+0x4c9/0x9c0 fs/splice.c:364 splice_direct_to_actor+0x2c4/0x9e0 fs/splice.c:1069 do_splice_direct+0x2ac/0x3f0 fs/splice.c:1194 do_sendfile+0x62c/0x1000 fs/read_write.c:1254 __do_sys_sendfile64 fs/read_write.c:1322 [inline] __se_sys_sendfile64+0x17c/0x1e0 fs/read_write.c:1308 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x45/0x110 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b -> #0 (sb_writers#4){.+.+}-{0:0}: check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain+0x1909/0x5ab0 kernel/locking/lockdep.c:3869 __lock_acquire+0x1345/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1e3/0x530 kernel/locking/lockdep.c:5754 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1635 [inline] sb_start_write+0x4d/0x1c0 include/linux/fs.h:1710 mnt_want_write+0x3f/0x90 fs/namespace.c:404 ovl_create_object+0x13b/0x360 fs/overlayfs/dir.c:629 lookup_open fs/namei.c:3477 [inline] open_last_lookups fs/namei.c:3546 [inline] path_openat+0x13fa/0x3290 fs/namei.c:3776 do_filp_open+0x234/0x490 fs/namei.c:3809 do_sys_openat2+0x13e/0x1d0 fs/open.c:1437 do_sys_open fs/open.c:1452 [inline] __do_sys_openat fs/open.c:1468 [inline] __se_sys_openat fs/open.c:1463 [inline] __x64_sys_openat+0x247/0x290 fs/open.c:1463 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x45/0x110 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b other info that might help us debug this: Chain exists of: sb_writers#4 --> &of->mutex --> &ovl_i_mutex_dir_key[depth] Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&ovl_i_mutex_dir_key[depth]); lock(&of->mutex); lock(&ovl_i_mutex_dir_key[depth]); rlock(sb_writers#4); *** DEADLOCK *** 2 locks held by syz-executor.2/10806: #0: ffff88807c774418 (sb_writers#23){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:404 #1: ffff88807d9caff0 (&ovl_i_mutex_dir_key[depth]){++++}-{3:3}, at: inode_lock include/linux/fs.h:802 [inline] #1: ffff88807d9caff0 (&ovl_i_mutex_dir_key[depth]){++++}-{3:3}, at: open_last_lookups fs/namei.c:3543 [inline] #1: ffff88807d9caff0 (&ovl_i_mutex_dir_key[depth]){++++}-{3:3}, at: path_openat+0x7bc/0x3290 fs/namei.c:3776 stack backtrace: CPU: 0 PID: 10806 Comm: syz-executor.2 Not tainted 6.7.0-rc7-syzkaller-00016-gf5837722ffec #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106 check_noncircular+0x366/0x490 kernel/locking/lockdep.c:2187 check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain+0x1909/0x5ab0 kernel/locking/lockdep.c:3869 __lock_acquire+0x1345/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1e3/0x530 kernel/locking/lockdep.c:5754 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1635 [inline] sb_start_write+0x4d/0x1c0 include/linux/fs.h:1710 mnt_want_write+0x3f/0x90 fs/namespace.c:404 ovl_create_object+0x13b/0x360 fs/overlayfs/dir.c:629 lookup_open fs/namei.c:3477 [inline] open_last_lookups fs/namei.c:3546 [inline] path_openat+0x13fa/0x3290 fs/namei.c:3776 do_filp_open+0x234/0x490 fs/namei.c:3809 do_sys_openat2+0x13e/0x1d0 fs/open.c:1437 do_sys_open fs/open.c:1452 [inline] __do_sys_openat fs/open.c:1468 [inline] __se_sys_openat fs/open.c:1463 [inline] __x64_sys_openat+0x247/0x290 fs/open.c:1463 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x45/0x110 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b RIP: 0033:0x7f24abc7cce9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 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 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f24aca1f0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f24abd9bf80 RCX: 00007f24abc7cce9 RDX: 0000000000141842 RSI: 0000000020000440 RDI: ffffffffffffff9c RBP: 00007f24abcc947a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f24abd9bf80 R15: 00007fff22dbe0c8