netlink: 12 bytes leftover after parsing attributes in process `syz.1.3454'. ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.1.3454/17654 is trying to acquire lock: ffff88802b2ad258 (&ovl_i_mutex_dir_key[depth]){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:884 [inline] ffff88802b2ad258 (&ovl_i_mutex_dir_key[depth]){++++}-{4:4}, at: lookup_slow fs/namei.c:1824 [inline] ffff88802b2ad258 (&ovl_i_mutex_dir_key[depth]){++++}-{4:4}, at: walk_component+0x345/0x5b0 fs/namei.c:2129 but task is already holding lock: ffff88803bbfa488 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x510 fs/kernfs/file.c:325 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (&of->mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:598 [inline] __mutex_lock+0x193/0x1060 kernel/locking/mutex.c:760 kernfs_seq_start+0x4d/0x240 fs/kernfs/file.c:154 seq_read_iter+0x2be/0x12c0 fs/seq_file.c:225 kernfs_fop_read_iter+0x40f/0x5a0 fs/kernfs/file.c:279 new_sync_read fs/read_write.c:491 [inline] vfs_read+0x8bf/0xcf0 fs/read_write.c:572 ksys_read+0x12a/0x250 fs/read_write.c:715 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #3 (&p->lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:598 [inline] __mutex_lock+0x193/0x1060 kernel/locking/mutex.c:760 seq_read_iter+0xe1/0x12c0 fs/seq_file.c:182 kernfs_fop_read_iter+0x40f/0x5a0 fs/kernfs/file.c:279 copy_splice_read+0x615/0xc20 fs/splice.c:363 do_splice_read fs/splice.c:982 [inline] do_splice_read+0x285/0x370 fs/splice.c:956 splice_file_to_pipe+0x109/0x120 fs/splice.c:1292 do_sendfile+0x400/0xe50 fs/read_write.c:1376 __do_sys_sendfile64 fs/read_write.c:1431 [inline] __se_sys_sendfile64 fs/read_write.c:1417 [inline] __x64_sys_sendfile64+0x1d8/0x220 fs/read_write.c:1417 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #2 (&pipe->mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:598 [inline] __mutex_lock+0x193/0x1060 kernel/locking/mutex.c:760 pipe_lock fs/pipe.c:91 [inline] pipe_lock+0x64/0x80 fs/pipe.c:88 iter_file_splice_write+0x1ea/0x12e0 fs/splice.c:683 do_splice_from fs/splice.c:938 [inline] do_splice+0x1478/0x1fc0 fs/splice.c:1351 __do_splice+0x32a/0x360 fs/splice.c:1433 __do_sys_splice fs/splice.c:1636 [inline] __se_sys_splice fs/splice.c:1618 [inline] __x64_sys_splice+0x187/0x250 fs/splice.c:1618 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (sb_writers#6){.+.+}-{0:0}: percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline] percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline] __sb_start_write include/linux/fs.h:1798 [inline] sb_start_write include/linux/fs.h:1934 [inline] mnt_want_write+0x6f/0x450 fs/namespace.c:557 ovl_fileattr_set+0x108/0x2c0 fs/overlayfs/inode.c:664 vfs_fileattr_set+0x779/0xb80 fs/file_attr.c:298 ioctl_fssetxattr+0x244/0x2c0 fs/file_attr.c:372 do_vfs_ioctl+0xc2b/0x14f0 fs/ioctl.c:567 __do_sys_ioctl fs/ioctl.c:596 [inline] __se_sys_ioctl fs/ioctl.c:584 [inline] __x64_sys_ioctl+0x114/0x210 fs/ioctl.c:584 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&ovl_i_mutex_dir_key[depth]){++++}-{4:4}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x12a6/0x1ce0 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5825 down_read+0x9b/0x480 kernel/locking/rwsem.c:1537 inode_lock_shared include/linux/fs.h:884 [inline] lookup_slow fs/namei.c:1824 [inline] walk_component+0x345/0x5b0 fs/namei.c:2129 lookup_last fs/namei.c:2630 [inline] path_lookupat+0x142/0x6d0 fs/namei.c:2654 filename_lookup+0x224/0x5f0 fs/namei.c:2683 kern_path+0x35/0x50 fs/namei.c:2816 lookup_bdev+0xd8/0x280 block/bdev.c:1205 resume_store+0x1d6/0x460 kernel/power/hibernate.c:1295 kobj_attr_store+0x55/0x80 lib/kobject.c:840 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145 kernfs_fop_write_iter+0x354/0x510 fs/kernfs/file.c:334 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x7d0/0x11d0 fs/read_write.c:686 ksys_write+0x12a/0x250 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 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: &ovl_i_mutex_dir_key[depth] --> &p->lock --> &of->mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&of->mutex); lock(&p->lock); lock(&of->mutex); rlock(&ovl_i_mutex_dir_key[depth]); *** DEADLOCK *** 4 locks held by syz.1.3454/17654: #0: ffff888013c00ef8 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2a2/0x370 fs/file.c:1232 #1: ffff88802c6ae428 (sb_writers#8){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738 #2: ffff88803bbfa488 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x510 fs/kernfs/file.c:325 #3: ffff888100abb008 (kn->active#66){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2b2/0x510 fs/kernfs/file.c:326 stack backtrace: CPU: 2 UID: 0 PID: 17654 Comm: syz.1.3454 Not tainted syzkaller #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:2043 check_noncircular+0x14c/0x170 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x12a6/0x1ce0 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5825 down_read+0x9b/0x480 kernel/locking/rwsem.c:1537 inode_lock_shared include/linux/fs.h:884 [inline] lookup_slow fs/namei.c:1824 [inline] walk_component+0x345/0x5b0 fs/namei.c:2129 lookup_last fs/namei.c:2630 [inline] path_lookupat+0x142/0x6d0 fs/namei.c:2654 filename_lookup+0x224/0x5f0 fs/namei.c:2683 kern_path+0x35/0x50 fs/namei.c:2816 lookup_bdev+0xd8/0x280 block/bdev.c:1205 resume_store+0x1d6/0x460 kernel/power/hibernate.c:1295 kobj_attr_store+0x55/0x80 lib/kobject.c:840 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145 kernfs_fop_write_iter+0x354/0x510 fs/kernfs/file.c:334 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x7d0/0x11d0 fs/read_write.c:686 ksys_write+0x12a/0x250 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd6f4d8ebe9 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:00007fd6f5b4a038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fd6f4fb5fa0 RCX: 00007fd6f4d8ebe9 RDX: 0000000000000012 RSI: 0000200000000000 RDI: 0000000000000003 RBP: 00007fd6f4e11e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fd6f4fb6038 R14: 00007fd6f4fb5fa0 R15: 00007ffc5eb53d48 PM: Image not found (code -6)