WARNING: possible circular locking dependency detected 6.13.0-rc3-syzkaller-00136-g8faabc041a00 #0 Not tainted ------------------------------------------------------ syz.3.1075/9950 is trying to acquire lock: ffff888025fc12e0 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_mq_exit_sched+0xd1/0x310 block/blk-mq-sched.c:531 but task is already holding lock: ffff8880264b28b8 (&eq->sysfs_lock){+.+.}-{4:4}, at: elevator_exit block/elevator.c:158 [inline] ffff8880264b28b8 (&eq->sysfs_lock){+.+.}-{4:4}, at: elevator_disable+0xb5/0x490 block/elevator.c:674 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (&eq->sysfs_lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x19b/0xa60 kernel/locking/mutex.c:735 elevator_exit block/elevator.c:158 [inline] elevator_disable+0xb5/0x490 block/elevator.c:674 blk_mq_elv_switch_none block/blk-mq.c:4942 [inline] __blk_mq_update_nr_hw_queues+0x41e/0x1590 block/blk-mq.c:5005 blk_mq_update_nr_hw_queues+0x2a/0x40 block/blk-mq.c:5068 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 -> #3 (&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 mpage_bio_submit_read fs/mpage.c:75 [inline] mpage_readahead+0x41d/0x590 fs/mpage.c:377 read_pages+0x1a8/0xdc0 mm/readahead.c:160 page_cache_ra_unbounded+0x3dc/0x750 mm/readahead.c:295 do_page_cache_ra mm/readahead.c:325 [inline] force_page_cache_ra+0x24b/0x340 mm/readahead.c:354 page_cache_sync_ra+0x110/0x9c0 mm/readahead.c:566 page_cache_sync_readahead include/linux/pagemap.h:1397 [inline] filemap_get_pages+0xd7b/0x1be0 mm/filemap.c:2546 filemap_read+0x3ca/0xd70 mm/filemap.c:2646 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 -> #2 (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:3203 [inline] filemap_fault+0x14a5/0x2820 mm/filemap.c:3344 __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:4354 [inline] kvm_mmu_faultin_pfn+0x469/0x1f30 arch/x86/kvm/mmu/mmu.c:4474 kvm_tdp_mmu_page_fault arch/x86/kvm/mmu/mmu.c:4642 [inline] kvm_tdp_page_fault+0x182/0x3d0 arch/x86/kvm/mmu/mmu.c:4678 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:6090 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 -> #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] __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 -> #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_mq_exit_sched+0xd1/0x310 block/blk-mq-sched.c:531 elevator_exit block/elevator.c:159 [inline] elevator_disable+0xc0/0x490 block/elevator.c:674 blk_mq_elv_switch_none block/blk-mq.c:4942 [inline] __blk_mq_update_nr_hw_queues+0x41e/0x1590 block/blk-mq.c:5005 blk_mq_update_nr_hw_queues+0x2a/0x40 block/blk-mq.c:5068 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 other info that might help us debug this: Chain exists of: &q->debugfs_mutex --> &q->q_usage_counter(io)#52 --> &eq->sysfs_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&eq->sysfs_lock); lock(&q->q_usage_counter(io)#52); lock(&eq->sysfs_lock); lock(&q->debugfs_mutex); *** DEADLOCK *** 7 locks held by syz.3.1075/9950: #0: ffff888025fbc998 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_ioctl+0x151/0xfd0 drivers/block/nbd.c:1572 #1: ffff888025fbc8d8 (&set->tag_list_lock){+.+.}-{4:4}, at: blk_mq_update_nr_hw_queues+0x20/0x40 block/blk-mq.c:5067 #2: ffff888025fc1030 (&q->sysfs_dir_lock){+.+.}-{4:4}, at: __blk_mq_update_nr_hw_queues+0x205/0x1590 block/blk-mq.c:4995 #3: ffff888025fc0fa0 (&q->sysfs_lock){+.+.}-{4:4}, at: __blk_mq_update_nr_hw_queues+0x214/0x1590 block/blk-mq.c:4996 #4: ffff888025fc0a70 (&q->q_usage_counter(io)#52){++++}-{0:0}, at: blk_mq_freeze_queue block/blk-mq.c:213 [inline] #4: ffff888025fc0a70 (&q->q_usage_counter(io)#52){++++}-{0:0}, at: __blk_mq_update_nr_hw_queues+0x21c/0x1590 block/blk-mq.c:4997 #5: ffff888025fc0aa8 (&q->q_usage_counter(queue)#36){+.+.}-{0:0}, at: blk_mq_freeze_queue block/blk-mq.c:213 [inline] #5: ffff888025fc0aa8 (&q->q_usage_counter(queue)#36){+.+.}-{0:0}, at: __blk_mq_update_nr_hw_queues+0x21c/0x1590 block/blk-mq.c:4997 #6: ffff8880264b28b8 (&eq->sysfs_lock){+.+.}-{4:4}, at: elevator_exit block/elevator.c:158 [inline] #6: ffff8880264b28b8 (&eq->sysfs_lock){+.+.}-{4:4}, at: elevator_disable+0xb5/0x490 block/elevator.c:674 stack backtrace: CPU: 3 UID: 0 PID: 9950 Comm: syz.3.1075 Not tainted 6.13.0-rc3-syzkaller-00136-g8faabc041a00 #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+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_mq_exit_sched+0xd1/0x310 block/blk-mq-sched.c:531 elevator_exit block/elevator.c:159 [inline] elevator_disable+0xc0/0x490 block/elevator.c:674 blk_mq_elv_switch_none block/blk-mq.c:4942 [inline] __blk_mq_update_nr_hw_queues+0x41e/0x1590 block/blk-mq.c:5005 blk_mq_update_nr_hw_queues+0x2a/0x40 block/blk-mq.c:5068 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 RIP: 0033:0x7f43a5b85d29 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:00007f43a69a7038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f43a5d76080 RCX: 00007f43a5b85d29 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000006 RBP: 00007f43a5c01aa8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f43a5d76080 R15: 00007ffdd30bcd18 block nbd3: shutting down sockets