====================================================== WARNING: possible circular locking dependency detected 6.13.0-rc7-syzkaller-00043-g619f0b6fad52 #0 Not tainted ------------------------------------------------------ syz.0.500/8247 is trying to acquire lock: ffff8880244a1ca8 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_register_queue+0x13c/0x4f0 block/blk-sysfs.c:774 but task is already holding lock: ffff8880244a1968 (&q->sysfs_lock){+.+.}-{4:4}, at: blk_register_queue+0x132/0x4f0 block/blk-sysfs.c:772 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #5 (&q->sysfs_lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x19b/0xa60 kernel/locking/mutex.c:735 blk_mq_elv_switch_none block/blk-mq.c:4932 [inline] __blk_mq_update_nr_hw_queues+0x446/0x1460 block/blk-mq.c:5010 blk_mq_update_nr_hw_queues+0x2a/0x40 block/blk-mq.c:5070 nbd_start_device+0x15b/0xd70 drivers/block/nbd.c:1413 nbd_start_device_ioctl drivers/block/nbd.c:1464 [inline] __nbd_ioctl drivers/block/nbd.c:1539 [inline] nbd_ioctl+0x21a/0xfd0 drivers/block/nbd.c:1579 compat_blkdev_ioctl+0x2f7/0x750 block/ioctl.c:749 __do_compat_sys_ioctl+0x1cb/0x2c0 fs/ioctl.c:1004 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e -> #4 (&q->q_usage_counter(io)#52){++++}-{0:0}: bio_queue_enter block/blk.h:75 [inline] blk_mq_submit_bio+0x1fb6/0x24c0 block/blk-mq.c:3090 __submit_bio+0x384/0x540 block/blk-core.c:629 __submit_bio_noacct_mq block/blk-core.c:710 [inline] submit_bio_noacct_nocheck+0x698/0xd70 block/blk-core.c:739 submit_bio_noacct+0x93a/0x1e20 block/blk-core.c:868 submit_bh fs/buffer.c:2819 [inline] block_read_full_folio+0x812/0xa50 fs/buffer.c:2446 filemap_read_folio+0xc6/0x2a0 mm/filemap.c:2357 filemap_update_page mm/filemap.c:2441 [inline] filemap_get_pages+0x155f/0x1be0 mm/filemap.c:2562 filemap_read+0x3ca/0xd70 mm/filemap.c:2637 blkdev_read_iter+0x187/0x480 block/fops.c:770 new_sync_read fs/read_write.c:484 [inline] vfs_read+0x87f/0xbe0 fs/read_write.c:565 ksys_read+0x12b/0x250 fs/read_write.c:708 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #3 (mapping.invalidate_lock#2){++++}-{4:4}: down_read+0x9a/0x330 kernel/locking/rwsem.c:1524 filemap_invalidate_lock_shared include/linux/fs.h:873 [inline] filemap_fault+0x2e0/0x2820 mm/filemap.c:3323 __do_fault+0x10a/0x490 mm/memory.c:4907 do_shared_fault mm/memory.c:5386 [inline] do_fault mm/memory.c:5460 [inline] do_pte_missing+0x1a8/0x3e00 mm/memory.c:3979 handle_pte_fault mm/memory.c:5801 [inline] __handle_mm_fault+0x103c/0x2a40 mm/memory.c:5944 handle_mm_fault+0x3fa/0xaa0 mm/memory.c:6112 do_user_addr_fault+0x60d/0x13f0 arch/x86/mm/fault.c:1338 handle_page_fault arch/x86/mm/fault.c:1481 [inline] exc_page_fault+0x5c/0xc0 arch/x86/mm/fault.c:1539 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 -> #2 (&vma->vm_lock->lock){++++}-{4:4}: down_write+0x93/0x200 kernel/locking/rwsem.c:1577 vma_start_write include/linux/mm.h:770 [inline] vma_link+0x26d/0x4a0 mm/vma.c:1691 insert_vm_struct+0x197/0x3f0 mm/mmap.c:1744 __bprm_mm_init fs/exec.c:289 [inline] bprm_mm_init fs/exec.c:393 [inline] alloc_bprm+0x6e0/0xc90 fs/exec.c:1544 kernel_execve+0xb0/0x3b0 fs/exec.c:1974 try_to_run_init_process init/main.c:1394 [inline] kernel_init+0x14a/0x2b0 init/main.c:1522 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 -> #1 (&mm->mmap_lock){++++}-{4:4}: __might_fault mm/memory.c:6751 [inline] __might_fault+0x11b/0x190 mm/memory.c:6744 _inline_copy_from_user include/linux/uaccess.h:162 [inline] _copy_from_user+0x29/0xd0 lib/usercopy.c:18 copy_from_user include/linux/uaccess.h:212 [inline] compat_blk_trace_setup+0xc9/0x200 kernel/trace/blktrace.c:664 blk_trace_ioctl+0x24a/0x290 kernel/trace/blktrace.c:745 compat_blkdev_ioctl+0x13c/0x750 block/ioctl.c:742 __do_compat_sys_ioctl+0x1cb/0x2c0 fs/ioctl.c:1004 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e -> #0 (&q->debugfs_mutex){+.+.}-{4:4}: check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain kernel/locking/lockdep.c:3904 [inline] __lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5226 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849 __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x19b/0xa60 kernel/locking/mutex.c:735 blk_register_queue+0x13c/0x4f0 block/blk-sysfs.c:774 add_disk_fwnode+0x785/0x1300 block/genhd.c:493 add_disk include/linux/blkdev.h:753 [inline] md_alloc+0x393/0x1030 drivers/md/md.c:5909 md_alloc_and_put drivers/md/md.c:5944 [inline] md_probe drivers/md/md.c:5957 [inline] md_probe+0x6e/0xd0 drivers/md/md.c:5952 blk_request_module+0x115/0x1e0 block/genhd.c:809 blkdev_get_no_open+0x7a/0xe0 block/bdev.c:783 bdev_file_open_by_dev block/bdev.c:1004 [inline] bdev_file_open_by_dev+0x6b/0x210 block/bdev.c:992 swsusp_check+0x78/0x410 kernel/power/swap.c:1569 software_resume+0x6d/0x400 kernel/power/hibernate.c:993 resume_store+0x249/0x460 kernel/power/hibernate.c:1271 kobj_attr_store+0x55/0x80 lib/kobject.c:840 sysfs_kf_write+0x117/0x170 fs/sysfs/file.c:139 kernfs_fop_write_iter+0x33d/0x500 fs/kernfs/file.c:334 new_sync_write fs/read_write.c:586 [inline] vfs_write+0x5ae/0x1150 fs/read_write.c:679 ksys_write+0x12b/0x250 fs/read_write.c:731 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e other info that might help us debug this: Chain exists of: &q->debugfs_mutex --> &q->q_usage_counter(io)#52 --> &q->sysfs_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&q->sysfs_lock); lock(&q->q_usage_counter(io)#52); lock(&q->sysfs_lock); lock(&q->debugfs_mutex); *** DEADLOCK *** 9 locks held by syz.0.500/8247: #0: ffff88806b6a0d38 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x267/0x390 fs/file.c:1192 #1: ffff888022dd6420 (sb_writers#8){.+.+}-{0:0}, at: ksys_write+0x12b/0x250 fs/read_write.c:731 #2: ffff888023fb3488 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x27b/0x500 fs/kernfs/file.c:325 #3: ffff888041691b48 (kn->active#69){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x29e/0x500 fs/kernfs/file.c:326 #4: ffffffff8dc80d08 (system_transition_mutex){+.+.}-{4:4}, at: software_resume+0x63/0x400 kernel/power/hibernate.c:992 #5: ffffffff8e8b90e8 (major_names_lock){+.+.}-{4:4}, at: blk_request_module+0x29/0x1e0 block/genhd.c:806 #6: ffffffff8f62ae88 (disks_mutex){+.+.}-{4:4}, at: md_alloc+0x3e/0x1030 drivers/md/md.c:5857 #7: ffff8880244a19f8 (&q->sysfs_dir_lock){+.+.}-{4:4}, at: blk_register_queue+0x5c/0x4f0 block/blk-sysfs.c:761 #8: ffff8880244a1968 (&q->sysfs_lock){+.+.}-{4:4}, at: blk_register_queue+0x132/0x4f0 block/blk-sysfs.c:772 stack backtrace: CPU: 2 UID: 0 PID: 8247 Comm: syz.0.500 Not tainted 6.13.0-rc7-syzkaller-00043-g619f0b6fad52 #0 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+0x41c/0x610 kernel/locking/lockdep.c:2074 check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2206 check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain kernel/locking/lockdep.c:3904 [inline] __lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5226 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849 __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x19b/0xa60 kernel/locking/mutex.c:735 blk_register_queue+0x13c/0x4f0 block/blk-sysfs.c:774 add_disk_fwnode+0x785/0x1300 block/genhd.c:493 add_disk include/linux/blkdev.h:753 [inline] md_alloc+0x393/0x1030 drivers/md/md.c:5909 md_alloc_and_put drivers/md/md.c:5944 [inline] md_probe drivers/md/md.c:5957 [inline] md_probe+0x6e/0xd0 drivers/md/md.c:5952 blk_request_module+0x115/0x1e0 block/genhd.c:809 blkdev_get_no_open+0x7a/0xe0 block/bdev.c:783 bdev_file_open_by_dev block/bdev.c:1004 [inline] bdev_file_open_by_dev+0x6b/0x210 block/bdev.c:992 swsusp_check+0x78/0x410 kernel/power/swap.c:1569 software_resume+0x6d/0x400 kernel/power/hibernate.c:993 resume_store+0x249/0x460 kernel/power/hibernate.c:1271 kobj_attr_store+0x55/0x80 lib/kobject.c:840 sysfs_kf_write+0x117/0x170 fs/sysfs/file.c:139 kernfs_fop_write_iter+0x33d/0x500 fs/kernfs/file.c:334 new_sync_write fs/read_write.c:586 [inline] vfs_write+0x5ae/0x1150 fs/read_write.c:679 ksys_write+0x12b/0x250 fs/read_write.c:731 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf7ff7579 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 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000f514655c EFLAGS: 00000296 ORIG_RAX: 0000000000000004 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000020000000 RDX: 0000000000000012 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 PM: Image not found (code -6) ---------------- 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: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi