====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.0.1927/12657 is trying to acquire lock: ffff88807726ec88 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:343 but task is already holding lock: ffff888023851868 (&pipe->mutex){+.+.}-{4:4}, at: pipe_lock fs/pipe.c:91 [inline] ffff888023851868 (&pipe->mutex){+.+.}-{4:4}, at: pipe_lock+0x69/0x80 fs/pipe.c:88 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&pipe->mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x1a2/0x1b90 kernel/locking/mutex.c:776 pipe_lock fs/pipe.c:91 [inline] pipe_lock+0x69/0x80 fs/pipe.c:88 iter_file_splice_write+0x1f8/0x10a0 fs/splice.c:683 do_splice_from fs/splice.c:938 [inline] do_splice+0x109c/0x1fd0 fs/splice.c:1351 __do_splice+0x33b/0x370 fs/splice.c:1433 __do_sys_splice fs/splice.c:1636 [inline] __se_sys_splice fs/splice.c:1618 [inline] __ia32_sys_splice+0x189/0x250 fs/splice.c:1618 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xde/0x660 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e -> #2 (sb_writers#5){.+.+}-{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/super.h:19 [inline] sb_start_write include/linux/fs/super.h:125 [inline] mnt_want_write+0x6f/0x450 fs/namespace.c:499 ovl_xattr_set+0x137/0x5a0 fs/overlayfs/xattrs.c:61 ovl_own_xattr_set+0x86/0xd0 fs/overlayfs/xattrs.c:204 __vfs_setxattr+0x175/0x1e0 fs/xattr.c:200 __vfs_setxattr_noperm+0x127/0x660 fs/xattr.c:234 __vfs_setxattr_locked+0x17d/0x250 fs/xattr.c:295 vfs_setxattr+0x140/0x330 fs/xattr.c:321 do_setxattr+0x145/0x180 fs/xattr.c:636 filename_setxattr+0x16e/0x1d0 fs/xattr.c:665 path_setxattrat+0x1ff/0x3a0 fs/xattr.c:713 __do_sys_setxattr fs/xattr.c:747 [inline] __se_sys_setxattr fs/xattr.c:743 [inline] __ia32_sys_setxattr+0xc4/0x140 fs/xattr.c:743 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xde/0x660 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e -> #1 (&ovl_i_mutex_dir_key[depth]#2){++++}-{4:4}: down_read+0x99/0x460 kernel/locking/rwsem.c:1537 inode_lock_shared include/linux/fs.h:1042 [inline] lookup_slow+0x42/0x70 fs/namei.c:1882 walk_component fs/namei.c:2229 [inline] lookup_last fs/namei.c:2730 [inline] path_lookupat+0x5e8/0xc40 fs/namei.c:2754 filename_lookup+0x202/0x590 fs/namei.c:2783 kern_path+0x35/0x50 fs/namei.c:2996 lookup_bdev+0xd8/0x280 block/bdev.c:1222 resume_store+0x1d6/0x460 kernel/power/hibernate.c:1306 kobj_attr_store+0x58/0x80 lib/kobject.c:840 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:142 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:352 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x6ac/0x1070 fs/read_write.c:686 ksys_write+0x12a/0x250 fs/read_write.c:738 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xde/0x660 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e -> #0 (&of->mutex){+.+.}-{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+0x14b8/0x2630 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x17c/0x330 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x1a2/0x1b90 kernel/locking/mutex.c:776 kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:343 iter_file_splice_write+0x82b/0x10a0 fs/splice.c:738 do_splice_from fs/splice.c:938 [inline] do_splice+0x109c/0x1fd0 fs/splice.c:1351 __do_splice+0x33b/0x370 fs/splice.c:1433 __do_sys_splice fs/splice.c:1636 [inline] __se_sys_splice fs/splice.c:1618 [inline] __ia32_sys_splice+0x189/0x250 fs/splice.c:1618 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xde/0x660 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e other info that might help us debug this: Chain exists of: &of->mutex --> sb_writers#5 --> &pipe->mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&pipe->mutex); lock(sb_writers#5); lock(&pipe->mutex); lock(&of->mutex); *** DEADLOCK *** 2 locks held by syz.0.1927/12657: #0: ffff88802a636420 (sb_writers#10){.+.+}-{0:0}, at: __do_splice+0x33b/0x370 fs/splice.c:1433 #1: ffff888023851868 (&pipe->mutex){+.+.}-{4:4}, at: pipe_lock fs/pipe.c:91 [inline] #1: ffff888023851868 (&pipe->mutex){+.+.}-{4:4}, at: pipe_lock+0x69/0x80 fs/pipe.c:88 stack backtrace: CPU: 0 UID: 0 PID: 12657 Comm: syz.0.1927 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_circular_bug.cold+0x178/0x1c7 kernel/locking/lockdep.c:2043 check_noncircular+0x146/0x160 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+0x14b8/0x2630 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x17c/0x330 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x1a2/0x1b90 kernel/locking/mutex.c:776 kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:343 iter_file_splice_write+0x82b/0x10a0 fs/splice.c:738 do_splice_from fs/splice.c:938 [inline] do_splice+0x109c/0x1fd0 fs/splice.c:1351 __do_splice+0x33b/0x370 fs/splice.c:1433 __do_sys_splice fs/splice.c:1636 [inline] __se_sys_splice fs/splice.c:1618 [inline] __ia32_sys_splice+0x189/0x250 fs/splice.c:1618 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xde/0x660 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf73ed579 Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 2e 8d b4 26 00 00 00 00 8d b4 26 00 00 00 RSP: 002b:00000000f541650c EFLAGS: 00000292 ORIG_RAX: 0000000000000139 RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 0000000000000000 RDX: 0000000000000009 RSI: 0000000000000000 RDI: 0000000000000011 RBP: 0000000000000004 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ---------------- Code disassembly (best guess), 2 bytes skipped: 0: 10 06 adc %al,(%rsi) 2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 6: 10 07 adc %al,(%rdi) 8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi c: 10 08 adc %cl,(%rax) e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1e: 00 51 52 add %dl,0x52(%rcx) 21: 55 push %rbp 22: 89 e5 mov %esp,%ebp 24: 0f 34 sysenter 26: cd 80 int $0x80 * 28: 5d pop %rbp <-- trapping instruction 29: 5a pop %rdx 2a: 59 pop %rcx 2b: c3 ret 2c: 90 nop 2d: 90 nop 2e: 90 nop 2f: 90 nop 30: 2e 8d b4 26 00 00 00 cs lea 0x0(%rsi,%riz,1),%esi 37: 00 38: 8d .byte 0x8d 39: b4 26 mov $0x26,%ah 3b: 00 00 add %al,(%rax)