====================================================== WARNING: possible circular locking dependency detected 6.13.0-rc6-syzkaller-00038-g09a0fa92e5b4 #0 Not tainted ------------------------------------------------------ syz.7.2371/15437 is trying to acquire lock: ffff8880286ddde0 (&q->sysfs_lock){+.+.}-{4:4}, at: blk_register_queue+0x132/0x4f0 block/blk-sysfs.c:772 but task is already holding lock: ffff8880286dde70 (&q->sysfs_dir_lock){+.+.}-{4:4}, at: blk_register_queue+0x5c/0x4f0 block/blk-sysfs.c:761 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #5 (&q->sysfs_dir_lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x19b/0xa60 kernel/locking/mutex.c:735 blk_mq_sysfs_unregister_hctxs+0x92/0x2d0 block/blk-mq-sysfs.c:278 __blk_mq_update_nr_hw_queues+0x93f/0x14e0 block/blk-mq.c:5015 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 blkdev_ioctl+0x276/0x6d0 block/ioctl.c:693 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl fs/ioctl.c:892 [inline] __x64_sys_ioctl+0x190/0x200 fs/ioctl.c:892 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 -> #4 (&q->q_usage_counter(io)#56){++++}-{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] page_cache_ra_unbounded+0x173/0x750 mm/readahead.c:226 do_page_cache_ra mm/readahead.c:325 [inline] page_cache_ra_order+0x8f2/0xc80 mm/readahead.c:524 do_sync_mmap_readahead mm/filemap.c:3194 [inline] filemap_fault+0x14a5/0x2820 mm/filemap.c:3335 __do_fault+0x10a/0x490 mm/memory.c:4907 do_read_fault mm/memory.c:5322 [inline] do_fault mm/memory.c:5456 [inline] do_pte_missing+0xebd/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 faultin_page mm/gup.c:1196 [inline] __get_user_pages+0x8d9/0x3b50 mm/gup.c:1494 __get_user_pages_locked mm/gup.c:1760 [inline] get_user_pages_unlocked+0x1c2/0x780 mm/gup.c:2737 hva_to_pfn_slow virt/kvm/kvm_main.c:2820 [inline] hva_to_pfn+0x8be/0xc20 virt/kvm/kvm_main.c:2916 kvm_follow_pfn virt/kvm/kvm_main.c:2963 [inline] kvm_follow_pfn+0x29f/0x3f0 virt/kvm/kvm_main.c:2947 __kvm_faultin_pfn+0x11c/0x1a0 virt/kvm/kvm_main.c:2984 __kvm_mmu_faultin_pfn arch/x86/kvm/mmu/mmu.c:4342 [inline] kvm_mmu_faultin_pfn+0x469/0x1f30 arch/x86/kvm/mmu/mmu.c:4462 kvm_tdp_mmu_page_fault arch/x86/kvm/mmu/mmu.c:4630 [inline] kvm_tdp_page_fault+0x182/0x3d0 arch/x86/kvm/mmu/mmu.c:4666 kvm_mmu_do_page_fault+0x58d/0x690 arch/x86/kvm/mmu/mmu_internal.h:325 kvm_mmu_page_fault+0x20f/0x1bb0 arch/x86/kvm/mmu/mmu.c:6078 handle_ept_violation+0x25a/0x640 arch/x86/kvm/vmx/vmx.c:5832 __vmx_handle_exit arch/x86/kvm/vmx/vmx.c:6620 [inline] vmx_handle_exit+0x733/0x1f70 arch/x86/kvm/vmx/vmx.c:6637 vcpu_enter_guest arch/x86/kvm/x86.c:11081 [inline] vcpu_run+0x3047/0x4f50 arch/x86/kvm/x86.c:11242 kvm_arch_vcpu_ioctl_run+0x44a/0x1740 arch/x86/kvm/x86.c:11560 kvm_vcpu_ioctl+0x6ce/0x1520 virt/kvm/kvm_main.c:4340 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl fs/ioctl.c:892 [inline] __x64_sys_ioctl+0x190/0x200 fs/ioctl.c:892 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 -> #2 (&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] __blk_trace_setup+0xa8/0x180 kernel/trace/blktrace.c:626 blk_trace_ioctl+0x163/0x290 kernel/trace/blktrace.c:740 blkdev_ioctl+0x109/0x6d0 block/ioctl.c:682 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl fs/ioctl.c:892 [inline] __x64_sys_ioctl+0x190/0x200 fs/ioctl.c:892 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 -> #1 (&q->debugfs_mutex){+.+.}-{4:4}: __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] brd_alloc.isra.0+0x5a2/0x840 drivers/block/brd.c:401 brd_init+0x12b/0x1d0 drivers/block/brd.c:481 do_one_initcall+0x128/0x700 init/main.c:1266 do_initcall_level init/main.c:1328 [inline] do_initcalls init/main.c:1344 [inline] do_basic_setup init/main.c:1363 [inline] kernel_init_freeable+0x5c7/0x900 init/main.c:1577 kernel_init+0x1c/0x2b0 init/main.c:1466 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 -> #0 (&q->sysfs_lock){+.+.}-{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+0x132/0x4f0 block/blk-sysfs.c:772 add_disk_fwnode+0x785/0x1300 block/genhd.c:493 add_disk include/linux/blkdev.h:753 [inline] md_alloc+0x3c2/0x1080 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 blkdev_open+0x13c/0x400 block/fops.c:620 do_dentry_open+0xf59/0x1ea0 fs/open.c:945 vfs_open+0x82/0x3f0 fs/open.c:1075 do_open fs/namei.c:3828 [inline] path_openat+0x1e6a/0x2d60 fs/namei.c:3987 do_filp_open+0x20c/0x470 fs/namei.c:4014 do_sys_openat2+0x17a/0x1e0 fs/open.c:1402 do_sys_open fs/open.c:1417 [inline] __do_sys_openat fs/open.c:1433 [inline] __se_sys_openat fs/open.c:1428 [inline] __x64_sys_openat+0x175/0x210 fs/open.c:1428 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 other info that might help us debug this: Chain exists of: &q->sysfs_lock --> &q->q_usage_counter(io)#56 --> &q->sysfs_dir_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&q->sysfs_dir_lock); lock(&q->q_usage_counter(io)#56); lock(&q->sysfs_dir_lock); lock(&q->sysfs_lock); *** DEADLOCK *** 3 locks held by syz.7.2371/15437: #0: ffffffff8ecc0d88 (major_names_lock){+.+.}-{4:4}, at: blk_request_module+0x29/0x1e0 block/genhd.c:806 #1: ffffffff8fa43a88 (disks_mutex){+.+.}-{4:4}, at: md_alloc+0x3e/0x1080 drivers/md/md.c:5857 #2: ffff8880286dde70 (&q->sysfs_dir_lock){+.+.}-{4:4}, at: blk_register_queue+0x5c/0x4f0 block/blk-sysfs.c:761 stack backtrace: CPU: 0 UID: 0 PID: 15437 Comm: syz.7.2371 Not tainted 6.13.0-rc6-syzkaller-00038-g09a0fa92e5b4 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_circular_bug+0x419/0x5d0 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+0x132/0x4f0 block/blk-sysfs.c:772 add_disk_fwnode+0x785/0x1300 block/genhd.c:493 add_disk include/linux/blkdev.h:753 [inline] md_alloc+0x3c2/0x1080 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 blkdev_open+0x13c/0x400 block/fops.c:620 do_dentry_open+0xf59/0x1ea0 fs/open.c:945 vfs_open+0x82/0x3f0 fs/open.c:1075 do_open fs/namei.c:3828 [inline] path_openat+0x1e6a/0x2d60 fs/namei.c:3987 do_filp_open+0x20c/0x470 fs/namei.c:4014 do_sys_openat2+0x17a/0x1e0 fs/open.c:1402 do_sys_open fs/open.c:1417 [inline] __do_sys_openat fs/open.c:1433 [inline] __se_sys_openat fs/open.c:1428 [inline] __x64_sys_openat+0x175/0x210 fs/open.c:1428 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 RIP: 0033:0x7ff0b3d85d29 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:00007ff0b4bd2038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007ff0b3f76080 RCX: 00007ff0b3d85d29 RDX: 0000000000000000 RSI: 0000000020000a80 RDI: ffffffffffffff9c RBP: 00007ff0b3e01b08 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007ff0b3f76080 R15: 00007ffd0ab2f658 block device autoloading is deprecated and will be removed.