====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.8.6122/25410 is trying to acquire lock: ffff888057173088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x510 fs/kernfs/file.c:325 but task is already holding lock: ffff88804080c868 (&pipe->mutex){+.+.}-{4:4}, at: pipe_lock fs/pipe.c:91 [inline] ffff88804080c868 (&pipe->mutex){+.+.}-{4:4}, at: pipe_lock+0x64/0x80 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: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+0x1475/0x1fc0 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 -> #2 (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_setattr+0x1c1/0x560 fs/overlayfs/inode.c:76 notify_change+0x6a9/0x1230 fs/attr.c:552 chown_common+0x54e/0x680 fs/open.c:791 do_fchownat+0x1a7/0x200 fs/open.c:822 __do_sys_lchown fs/open.c:847 [inline] __se_sys_lchown fs/open.c:845 [inline] __x64_sys_lchown+0x7e/0xc0 fs/open.c:845 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 (&ovl_i_mutex_dir_key[depth]){++++}-{4:4}: 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 -> #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+0x12a6/0x1ce0 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:598 [inline] __mutex_lock+0x193/0x1060 kernel/locking/mutex.c:760 kernfs_fop_write_iter+0x28f/0x510 fs/kernfs/file.c:325 iter_file_splice_write+0xa21/0x12e0 fs/splice.c:738 do_splice_from fs/splice.c:938 [inline] do_splice+0x1475/0x1fc0 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 other info that might help us debug this: Chain exists of: &of->mutex --> sb_writers#6 --> &pipe->mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&pipe->mutex); lock(sb_writers#6); lock(&pipe->mutex); lock(&of->mutex); *** DEADLOCK *** 2 locks held by syz.8.6122/25410: #0: ffff88803a536428 (sb_writers#11){.+.+}-{0:0}, at: __do_splice+0x32a/0x360 fs/splice.c:1433 #1: ffff88804080c868 (&pipe->mutex){+.+.}-{4:4}, at: pipe_lock fs/pipe.c:91 [inline] #1: ffff88804080c868 (&pipe->mutex){+.+.}-{4:4}, at: pipe_lock+0x64/0x80 fs/pipe.c:88 stack backtrace: CPU: 3 UID: 0 PID: 25410 Comm: syz.8.6122 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 __mutex_lock_common kernel/locking/mutex.c:598 [inline] __mutex_lock+0x193/0x1060 kernel/locking/mutex.c:760 kernfs_fop_write_iter+0x28f/0x510 fs/kernfs/file.c:325 iter_file_splice_write+0xa21/0x12e0 fs/splice.c:738 do_splice_from fs/splice.c:938 [inline] do_splice+0x1475/0x1fc0 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 RIP: 0033:0x7f16c0f8ebe9 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:00007f16c1d85038 EFLAGS: 00000246 ORIG_RAX: 0000000000000113 RAX: ffffffffffffffda RBX: 00007f16c11b5fa0 RCX: 00007f16c0f8ebe9 RDX: 0000000000000006 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00007f16c1011e19 R08: 0000000000000049 R09: 0000000000000002 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f16c11b6038 R14: 00007f16c11b5fa0 R15: 00007ffe75229918