====================================================== WARNING: possible circular locking dependency detected 6.14.0-syzkaller-g56f944529ec2 #0 Not tainted ------------------------------------------------------ syz.0.16/6243 is trying to acquire lock: ffff8880287b7888 (&of->mutex){+.+.}-{4:4}, at: kernfs_seq_start+0x4d/0x240 fs/kernfs/file.c:154 but task is already holding lock: ffff88802a6da1c8 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x12c0 fs/seq_file.c:182 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (&p->lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:601 [inline] __mutex_lock+0x199/0xb90 kernel/locking/mutex.c:746 seq_read_iter+0xe1/0x12c0 fs/seq_file.c:182 kernfs_fop_read_iter+0x40f/0x5a0 fs/kernfs/file.c:279 copy_splice_read+0x615/0xba0 fs/splice.c:363 do_splice_read fs/splice.c:979 [inline] do_splice_read+0x282/0x370 fs/splice.c:953 splice_file_to_pipe+0x109/0x120 fs/splice.c:1289 do_sendfile+0x400/0xe50 fs/read_write.c:1374 __do_sys_sendfile64 fs/read_write.c:1429 [inline] __se_sys_sendfile64 fs/read_write.c:1415 [inline] __x64_sys_sendfile64+0x1d8/0x220 fs/read_write.c:1415 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #3 (&pipe->mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:601 [inline] __mutex_lock+0x199/0xb90 kernel/locking/mutex.c:746 pipe_lock fs/pipe.c:92 [inline] pipe_lock+0x64/0x80 fs/pipe.c:89 iter_file_splice_write+0x1ea/0x1150 fs/splice.c:683 backing_file_splice_write+0x27c/0x890 fs/backing-file.c:315 ovl_splice_write+0x38d/0x630 fs/overlayfs/file.c:440 do_splice_from fs/splice.c:935 [inline] do_splice+0x1475/0x1fc0 fs/splice.c:1348 __do_splice+0x32a/0x360 fs/splice.c:1430 __do_sys_splice fs/splice.c:1633 [inline] __se_sys_splice fs/splice.c:1615 [inline] __x64_sys_splice+0x187/0x250 fs/splice.c:1615 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #2 (sb_writers#6){.+.+}-{0:0}: percpu_down_read include/linux/percpu-rwsem.h:52 [inline] __sb_start_write include/linux/fs.h:1783 [inline] sb_start_write include/linux/fs.h:1919 [inline] mnt_want_write+0x6f/0x450 fs/namespace.c:556 ovl_create_object+0x12c/0x300 fs/overlayfs/dir.c:628 lookup_open.isra.0+0x11d0/0x1580 fs/namei.c:3666 open_last_lookups fs/namei.c:3765 [inline] path_openat+0x905/0x2d40 fs/namei.c:4001 do_filp_open+0x20b/0x470 fs/namei.c:4031 do_sys_openat2+0x11b/0x1d0 fs/open.c:1429 do_sys_open fs/open.c:1444 [inline] __do_sys_open fs/open.c:1452 [inline] __se_sys_open fs/open.c:1448 [inline] __x64_sys_open+0x153/0x1e0 fs/open.c:1448 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&ovl_i_mutex_dir_key[depth]){++++}-{4:4}: down_read+0x9b/0x480 kernel/locking/rwsem.c:1524 inode_lock_shared include/linux/fs.h:877 [inline] lookup_slow fs/namei.c:1823 [inline] walk_component+0x345/0x5b0 fs/namei.c:2128 lookup_last fs/namei.c:2626 [inline] path_lookupat+0x17e/0x780 fs/namei.c:2650 filename_lookup+0x224/0x5f0 fs/namei.c:2679 kern_path+0x35/0x50 fs/namei.c:2787 lookup_bdev+0xd8/0x280 block/bdev.c:1167 resume_store+0x1d6/0x460 kernel/power/hibernate.c:1248 kobj_attr_store+0x55/0x80 lib/kobject.c:840 sysfs_kf_write+0xef/0x150 fs/sysfs/file.c:145 kernfs_fop_write_iter+0x351/0x510 fs/kernfs/file.c:334 new_sync_write fs/read_write.c:591 [inline] vfs_write+0x5ba/0x1180 fs/read_write.c:684 ksys_write+0x12a/0x240 fs/read_write.c:736 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&of->mutex){+.+.}-{4:4}: check_prev_add kernel/locking/lockdep.c:3166 [inline] check_prevs_add kernel/locking/lockdep.c:3285 [inline] validate_chain kernel/locking/lockdep.c:3909 [inline] __lock_acquire+0x1173/0x1ba0 kernel/locking/lockdep.c:5235 lock_acquire kernel/locking/lockdep.c:5866 [inline] lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5823 __mutex_lock_common kernel/locking/mutex.c:601 [inline] __mutex_lock+0x199/0xb90 kernel/locking/mutex.c:746 kernfs_seq_start+0x4d/0x240 fs/kernfs/file.c:154 traverse.part.0.constprop.0+0xac/0x640 fs/seq_file.c:106 traverse fs/seq_file.c:98 [inline] seq_read_iter+0x932/0x12c0 fs/seq_file.c:195 kernfs_fop_read_iter+0x40f/0x5a0 fs/kernfs/file.c:279 copy_splice_read+0x615/0xba0 fs/splice.c:363 do_splice_read fs/splice.c:979 [inline] do_splice_read+0x282/0x370 fs/splice.c:953 splice_file_to_pipe+0x109/0x120 fs/splice.c:1289 do_sendfile+0x400/0xe50 fs/read_write.c:1374 __do_sys_sendfile64 fs/read_write.c:1429 [inline] __se_sys_sendfile64 fs/read_write.c:1415 [inline] __x64_sys_sendfile64+0x1d8/0x220 fs/read_write.c:1415 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: &of->mutex --> &pipe->mutex --> &p->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&p->lock); lock(&pipe->mutex); lock(&p->lock); lock(&of->mutex); *** DEADLOCK *** 2 locks held by syz.0.16/6243: #0: ffff888050075c68 (&pipe->mutex){+.+.}-{4:4}, at: pipe_lock fs/pipe.c:92 [inline] #0: ffff888050075c68 (&pipe->mutex){+.+.}-{4:4}, at: pipe_lock+0x64/0x80 fs/pipe.c:89 #1: ffff88802a6da1c8 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x12c0 fs/seq_file.c:182 stack backtrace: CPU: 0 UID: 0 PID: 6243 Comm: syz.0.16 Not tainted 6.14.0-syzkaller-g56f944529ec2 #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_circular_bug+0x275/0x350 kernel/locking/lockdep.c:2079 check_noncircular+0x14c/0x170 kernel/locking/lockdep.c:2211 check_prev_add kernel/locking/lockdep.c:3166 [inline] check_prevs_add kernel/locking/lockdep.c:3285 [inline] validate_chain kernel/locking/lockdep.c:3909 [inline] __lock_acquire+0x1173/0x1ba0 kernel/locking/lockdep.c:5235 lock_acquire kernel/locking/lockdep.c:5866 [inline] lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5823 __mutex_lock_common kernel/locking/mutex.c:601 [inline] __mutex_lock+0x199/0xb90 kernel/locking/mutex.c:746 kernfs_seq_start+0x4d/0x240 fs/kernfs/file.c:154 traverse.part.0.constprop.0+0xac/0x640 fs/seq_file.c:106 traverse fs/seq_file.c:98 [inline] seq_read_iter+0x932/0x12c0 fs/seq_file.c:195 kernfs_fop_read_iter+0x40f/0x5a0 fs/kernfs/file.c:279 copy_splice_read+0x615/0xba0 fs/splice.c:363 do_splice_read fs/splice.c:979 [inline] do_splice_read+0x282/0x370 fs/splice.c:953 splice_file_to_pipe+0x109/0x120 fs/splice.c:1289 do_sendfile+0x400/0xe50 fs/read_write.c:1374 __do_sys_sendfile64 fs/read_write.c:1429 [inline] __se_sys_sendfile64 fs/read_write.c:1415 [inline] __x64_sys_sendfile64+0x1d8/0x220 fs/read_write.c:1415 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe58b985d29 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fe58c869038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007fe58bb76080 RCX: 00007fe58b985d29 RDX: 0000000000000000 RSI: 0000000000000007 RDI: 0000000000000006 RBP: 00007fe58ba01b08 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fe58bb76080 R15: 00007ffcfa724c98