====================================================== WARNING: possible circular locking dependency detected 5.15.170-syzkaller #0 Not tainted ------------------------------------------------------ syz.1.1233/9717 is trying to acquire lock: ffff888064db8488 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e7/0x4f0 fs/kernfs/file.c:287 but task is already holding lock: ffff8880243d5468 (&pipe->mutex/1){+.+.}-{3:3}, at: iter_file_splice_write+0x2ab/0xfa0 fs/splice.c:635 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #7 (&pipe->mutex/1){+.+.}-{3:3}: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 iter_file_splice_write+0x2ab/0xfa0 fs/splice.c:635 do_splice_from fs/splice.c:767 [inline] do_splice+0xfe6/0x1790 fs/splice.c:1079 __do_splice fs/splice.c:1144 [inline] __do_sys_splice fs/splice.c:1350 [inline] __se_sys_splice+0x340/0x420 fs/splice.c:1332 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #6 (sb_writers#3){.+.+}-{0:0}: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1813 [inline] sb_start_write include/linux/fs.h:1883 [inline] file_start_write include/linux/fs.h:3044 [inline] lo_write_bvec+0x1a3/0x740 drivers/block/loop.c:315 lo_write_simple drivers/block/loop.c:338 [inline] do_req_filebacked drivers/block/loop.c:656 [inline] loop_handle_cmd drivers/block/loop.c:2234 [inline] loop_process_work+0x2309/0x2af0 drivers/block/loop.c:2274 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457 kthread+0x3f6/0x4f0 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 -> #5 ((work_completion)(&worker->work)){+.+.}-{0:0}: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 process_one_work+0x7f1/0x10c0 kernel/workqueue.c:2286 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457 kthread+0x3f6/0x4f0 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 -> #4 ((wq_completion)loop7){+.+.}-{0:0}: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 flush_workqueue+0x170/0x1610 kernel/workqueue.c:2830 drain_workqueue+0xc5/0x390 kernel/workqueue.c:2995 destroy_workqueue+0x7b/0xae0 kernel/workqueue.c:4439 __loop_clr_fd+0x241/0xbe0 drivers/block/loop.c:1383 blkdev_put_whole block/bdev.c:692 [inline] blkdev_put+0x455/0x790 block/bdev.c:954 deactivate_locked_super+0xa0/0x110 fs/super.c:335 cleanup_mnt+0x44e/0x500 fs/namespace.c:1143 task_work_run+0x129/0x1a0 kernel/task_work.c:188 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop+0x106/0x130 kernel/entry/common.c:181 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x5d/0x240 kernel/entry/common.c:307 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #3 (&lo->lo_mutex){+.+.}-{3:3}: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_killable_nested+0x17/0x20 kernel/locking/mutex.c:758 lo_open+0x68/0x100 drivers/block/loop.c:2055 blkdev_get_whole+0x94/0x390 block/bdev.c:669 blkdev_get_by_dev+0x2bc/0xa50 block/bdev.c:824 blkdev_open+0x138/0x2d0 block/fops.c:463 do_dentry_open+0x807/0xfb0 fs/open.c:826 do_open fs/namei.c:3608 [inline] path_openat+0x2705/0x2f20 fs/namei.c:3742 do_filp_open+0x21c/0x460 fs/namei.c:3769 do_sys_openat2+0x13b/0x4f0 fs/open.c:1253 do_sys_open fs/open.c:1269 [inline] __do_sys_openat fs/open.c:1285 [inline] __se_sys_openat fs/open.c:1280 [inline] __x64_sys_openat+0x243/0x290 fs/open.c:1280 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #2 (&disk->open_mutex){+.+.}-{3:3}: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 blkdev_get_by_dev+0x14d/0xa50 block/bdev.c:817 swsusp_check+0xb1/0x2c0 kernel/power/swap.c:1526 software_resume+0xc6/0x3c0 kernel/power/hibernate.c:977 resume_store+0xe3/0x130 kernel/power/hibernate.c:1179 kernfs_fop_write_iter+0x3a2/0x4f0 fs/kernfs/file.c:296 call_write_iter include/linux/fs.h:2174 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0xacd/0xe50 fs/read_write.c:594 ksys_write+0x1a2/0x2c0 fs/read_write.c:647 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #1 (system_transition_mutex/1){+.+.}-{3:3}: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 software_resume+0x7c/0x3c0 kernel/power/hibernate.c:932 resume_store+0xe3/0x130 kernel/power/hibernate.c:1179 kernfs_fop_write_iter+0x3a2/0x4f0 fs/kernfs/file.c:296 call_write_iter include/linux/fs.h:2174 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0xacd/0xe50 fs/read_write.c:594 ksys_write+0x1a2/0x2c0 fs/read_write.c:647 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #0 (&of->mutex){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 kernfs_fop_write_iter+0x1e7/0x4f0 fs/kernfs/file.c:287 do_iter_readv_writev+0x594/0x7a0 do_iter_write+0x1e6/0x760 fs/read_write.c:855 iter_file_splice_write+0x806/0xfa0 fs/splice.c:689 do_splice_from fs/splice.c:767 [inline] do_splice+0xfe6/0x1790 fs/splice.c:1079 __do_splice fs/splice.c:1144 [inline] __do_sys_splice fs/splice.c:1350 [inline] __se_sys_splice+0x340/0x420 fs/splice.c:1332 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 other info that might help us debug this: Chain exists of: &of->mutex --> sb_writers#3 --> &pipe->mutex/1 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&pipe->mutex/1); lock(sb_writers#3); lock(&pipe->mutex/1); lock(&of->mutex); *** DEADLOCK *** 2 locks held by syz.1.1233/9717: #0: ffff88802b50c460 (sb_writers#8){.+.+}-{0:0}, at: __do_splice fs/splice.c:1144 [inline] #0: ffff88802b50c460 (sb_writers#8){.+.+}-{0:0}, at: __do_sys_splice fs/splice.c:1350 [inline] #0: ffff88802b50c460 (sb_writers#8){.+.+}-{0:0}, at: __se_sys_splice+0x340/0x420 fs/splice.c:1332 #1: ffff8880243d5468 (&pipe->mutex/1){+.+.}-{3:3}, at: iter_file_splice_write+0x2ab/0xfa0 fs/splice.c:635 stack backtrace: CPU: 0 PID: 9717 Comm: syz.1.1233 Not tainted 5.15.170-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106 check_noncircular+0x2f8/0x3b0 kernel/locking/lockdep.c:2133 check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __mutex_lock_common+0x1da/0x25a0 kernel/locking/mutex.c:596 __mutex_lock kernel/locking/mutex.c:729 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743 kernfs_fop_write_iter+0x1e7/0x4f0 fs/kernfs/file.c:287 do_iter_readv_writev+0x594/0x7a0 do_iter_write+0x1e6/0x760 fs/read_write.c:855 iter_file_splice_write+0x806/0xfa0 fs/splice.c:689 do_splice_from fs/splice.c:767 [inline] do_splice+0xfe6/0x1790 fs/splice.c:1079 __do_splice fs/splice.c:1144 [inline] __do_sys_splice fs/splice.c:1350 [inline] __se_sys_splice+0x340/0x420 fs/splice.c:1332 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f92bc820719 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:00007f92bac77038 EFLAGS: 00000246 ORIG_RAX: 0000000000000113 RAX: ffffffffffffffda RBX: 00007f92bc9d8058 RCX: 00007f92bc820719 RDX: 0000000000000005 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00007f92bc89332e R08: 000000000000bfcd R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007f92bc9d8058 R15: 00007ffda0289488